Audi TT 8 User Manual

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Service

Workshop Manual

Audi TT 1999 ➤

Running gear, self-diagnosis

Edition 07.2004

Service Department. Technical Information

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by AUDI AG.

Service

List of Workshop Manual Repair GroupsList of Workshop Manual Repair GroupsList of Workshop Manual Repair Groups

Re pa ir G ro up

01 - Self-diagnosis, electrical checks

Technical information should always be available to the foremen and mechanics, because their careful and constant adherence to the instructions is essential to ensure vehicle road-worthiness and safety. In addition, the normal basic safety precautions for working on motor vehicles must, as a matter of course, be observed.

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by AUDI AG.

Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

Contents

01 - Self-diagnosis, electrical checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1 Self-diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1 Basic notes on self-diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 Function of the individual systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.3 Safety precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.4 Requirements for test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.5 Fault finding procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.6 Road test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

1.7 Connecting vehicle diagnostic, testing and information system VAS 5051 A . . . . . . . . . . 7

2 CAN bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.1 Testing a “two-wire data bus system” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3 ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.1 Electrical/electronic components and fitting locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.2 Faults displayed by warning lamps in instrument cluster . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.3 Performing self-diagnosis on the ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.4 Interrogating fault memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3.5 Fault tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3.6 Final control diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

3.7 Basic setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

3.8 Erasing fault memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

3.9 End output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

3.10 Renewing and coding control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

3.11 Measured value block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

3.12 Login procedure or coding II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

3.13 Electrical check of ABS/EDL and ABS/EDL/TCS ITT Mark 20 without ESP . . . . . . . . . . . . 47

3.14 Connecting adapter V.A.G 1598/21 (test box) to ABS with EDL control unit J104 . . . . . . 48

3.15 Test table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

4 ABS/EDL/TCS/ESP ITT Mark 20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

4.1 Retrofit installation of ESP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

4.2 Electrical/electronic components and fitting locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

4.3 Faults displayed by warning lamps in instrument cluster . . . . . . . . . . . . . . . . . . . . . . . . . . 62

4.4 Performing self-diagnosis of ABS/EDL/TCS/ESP ITT Mark 20 system . . . . . . . . . . . . . . . . 65

4.5 Interrogating fault memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

4.6 Fault tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

4.7 Final control diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

4.8 Basic setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

4.9 Performing zero compensation of steering angle sender G85 . . . . . . . . . . . . . . . . . . . . . . 99

4.10 Erasing fault memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

4.11 End output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

4.12 Renewing and coding control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

4.13 Measured value block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

4.14 Login procedure or coding II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

4.15 Electrical check of ABS/EDL/TCS/ESP ITT MARK 20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

4.16 Connecting test box V.A.G 1598 A with adapter cable (47-pin) V.A.G 1598/33 to ABS with

EDL control unit J104 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

4.17 Test table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

5 ABS/ESP, MK 60 Continental Teves Mark 60; Electronic Stabilisation Program, Continental

Teves Mark 60 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

5.1 This self-diagnosis system is described exclusively in the “Guided fault finding” . . . . . . . . 133

Contents i

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

ii Contents

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Running gear, self-diagnosis - Edition 07.2004

01 – Self-diagnosis, electrical checks

1 Self-diagnosis

1.1 Basic notes on self-diagnosis

♦ The control unit of a system with self-diagnosis function de‐

tects any faults or malfunctions during vehicle operation and stores them in a fault memory. This information will remain available even if the system voltage fails.

♦ The self-diagnosis function enables faults to be traced quickly

and efficiently. The self-diagnosis functions available can be implemented via vehicle diagnostic, testing and information system -VAS 5051 A- or vehicle diagnosis and service infor‐ mation system -VAS 5052- .

Note

Audi TT 1999 ➤

This Workshop Manual describes how to perform self-diagnosis using vehicle diagnostic, testing and information system VAS 5051 A- .

♦ The respective control unit and the vehicle diagnostic, testing

and information system -VAS 5051 A- must be able to ex‐ change data in order to communicate with each other. The diagnostic connector is the interface for communication be‐ tween the control unit and vehicle diagnostic, testing and information system -VAS 5051 A- .

Fault detection by ABS with EDL control unit -J104-

♦ The control unit detects any faults which may occur during ve‐

hicle operation and stores them in a fault memory.

♦ To commence fault finding, initiate self-diagnosis and inter‐

rogate the stored faults. It is necessary to interrogate the fault memories of all vehicle systems with self-diagnosis capability since the ABS with EDL control unit -J104- exchanges data with the engine control unit as well as the steering angle send‐ er -G85- and the four-wheel drive control unit -J492- (if fitted). Select function “00 - Interrogating fault memory - Complete system” ⇒ page 7 .If faults are stored in any other systems, check whether the stored faults affect the ABS/EDL/TCS/ESP system by referring to the respective fault tables.

♦ After evaluating all received data, the ABS with EDL control

unit -J104- distinguishes between sporadic faults (occurring intermittently) and static faults (permanently present for a de‐ fined period), and stores these faults in an internal memory.

♦ If a fault occurs, it is initially stored as being static. If the fault

does not reoccur over a certain period of time or while the ve‐ hicle is driven a certain distance, it is then stored as sporadic fault.

♦ When interrogating the fault memory, sporadic faults are

marked as “sporadic” on the display.

♦ A fault is also stored as sporadic if the ignition is switched off

and on again while the fault memory is being interrogated, or if the fault memory is not erased after performing repairs.

♦ Sporadic faults are erased automatically if they do not occur

again within the next 50 vehicle starts and driving off sequen‐ ces (road speed greater than 20 km/h).

1. Self-diagnosis 1

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

♦ The ABS with EDL control unit -J104- is able to detect whether

any of the required signals are not being transmitted via the CAN bus.However, defective CAN bus wires (e.g. open circuit) cannot be detected directly. The defective CAN bus wires can only be traced after interrogating the fault memories of all con‐ trol units ⇒ page 9 .

♦ Sporadic faults affecting the CAN bus are erased automati‐

cally if they do not occur again within the next 15 vehicle starts and driving off sequences (vehicle speed greater than 20 km/ h).

1.2 Function of the individual systems

1.2.1 Anti-lock brake system

The anti-lock brake system (ABS) prevents the wheels from lock‐ ing when the brakes are applied by the driver. Directional stability and steerability are maintained in spite of high braking effect.

1.2.2 EDL - Electronic differential lock

The EDL system assists pulling away; it acts only on the front wheels, even if the vehicle is equipped with four-wheel drive.An electronically controlled brake application on the spinning driven wheel provides a torque reaction point for the differential. This enables the wheel with better traction to make use of the engine power. The EDL is effective in both forwards and reverse direc‐ tions. The EDL control process is available up to a road speed of 80 km/h.

1.2.3 EBPD - Electronic brake pressure distri‐ bution

The Audi TT is not fitted with a mechanical brake pressure regu‐ lator. Specially developed software in the ABS with EDL control unit -J104- provides electronic brake force distribution (EBPD) and limits the brake pressure applied to the rear wheels.

1.2.4 TCS - Traction control system

♦ TCS (traction control system) is fitted only on vehicles with

front-wheel drive. The TCS limits the engine power to prevent the driven wheels from spinning under acceleration. The sys‐ tem operates by reducing engine torque and is active at all speeds. The EDL and TCS functions act together to assist ac‐ celeration. The warning lamp -1- flashes at a rate of three times per second when the control function is working.

♦ The TCS requires an exchange of data between ABS with EDL

control unit -J104- and the engine control unit. The control units communicate with each other. The data is transmitted via CAN bus ⇒ page 9 .

♦ Depending on the engine version, the TCS also incorporates

an engine braking control (EBC). EBC prevents the driven wheels from locking up due to excessive engine braking tor‐ que, for instance when the driver changes down from 3rd to 2nd gear. The engine braking effect is reduced via the elec‐ tronic idling stabilisation control.

♦ If required, the TCS function can be switched off (and on

again) by means of the button -2- (marked ASR) in the centre of the dash panel. The TCS button has no influence on EBC. The warning lamp lights up when the TCS is switched off. The TCS is re-activated when the ignition is switched on again.

2 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

1.2.5 ESP - Electronic Stabilisation Program

The ESP is based on the existing on-board safety systems ABS/ EDL and ABS/EDL/TCS, with a number of additional capabilities. ESP enhances the degree of control in critical dynamic condi‐ tions. In addition to the existing safety systems, ESP further reduces the risk of skidding and improves steerability.

Caution

However, ESP is not able to overcome the physical limits of the available road adhesion.

♦ The ESP is designed to stabilise the dynamic handling re‐

sponse of the vehicle by counteracting any tendency towards oversteer or understeer. The functions of EBPD, ABS, EDL and TCS are incorporated in the control system. However, the characteristic function of the ESP is controlled brake applica‐ tion at individual wheels.

♦ The ESP function relies on an exchange of signals between

ABS with EDL control unit -J104- and the engine control unit, the steering angle sender -G85- and the four-wheel drive con‐ trol unit -J492- (if fitted). The data is transmitted via CAN bus

⇒ page 9 .

♦ If required, the TCS function and the ESP function can be

switched off (and on again) by means of the button -2- (marked ASR) in the dash panel. The control unit ignores the position of the ESP switch when the driver presses the brake pedal. ESP will remain active at all times during braking. Both func‐ tions, TCS and ESP, will be activated again automatically the next time the ignition is switched on.

♦ When the TCS and ESP function are deactivated, the ESP and

TCS warning lamp -K155- -item 1- in the instrument cluster lights up. The warning lamp flashes at a rate of three times per second when the control function is actually working.

Audi TT 1999 ➤

Examples:

In an oversteer condition, the rear of the vehicle tends to break away. The vehicle rotates further about its vertical axis than is required to maintain course through the corner. The system coun‐ teracts this moment of vehicle oversteer by applying a controlled braking force at the outside front wheel -arrow-.

1. Self-diagnosis 3

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

In an understeer condition the front end of the vehicle does not follow the required corner radius. The vehicle breaks away to‐ wards the outside of the bend. The vehicle does not rotate far enough about its vertical axis to maintain course through the cor‐ ner. The system increases the amount of rotation by applying a controlled braking force at the inside rear wheel -arrow-.

1.3 Safety precautions

♦ The ABS/EDL/TCS and ESP are safety systems; knowledge

of the systems is essential for performing repair work

♦ Always switch off the ignition before carrying out installation

or repair work.

♦ Ensure that no brake fluid enters electrical connectors.

WARNING

♦ To avoid any risk of accident, observe the following pre‐

cautions when using test instruments while road testing the vehicle:

Audi TT Coupé:

♦ Use only vehicle diagnostic, testing and information sys‐

tem -VAS 5051 A- or vehicle diagnosis and service infor‐ mation system -VAS 5052- to read measured value blocks. The tester must always be secured on the rear seat and operated from there by a second person.

♦ Due to the limited space, slide the front passenger's seat

forwards as far as it will go and (without pulling the release lever) incline the backrest as far forwards as possible by turning the adjuster knob. Do not operate the release lever to tilt the backrest forward.

Audi TT Roadster:

♦ In the Audi TT Roadster, use only vehicle diagnosis and

service information system -VAS 5052- with the front pas‐ senger's airbag de-activated.

♦ Switch off the front passenger's airbag by means of the

key-operated switch in the glove box or via self-diagnosis ⇒ Body, self-diagnosis; Rep. Gr. 01 .

♦ Reactivate front passenger's airbag after testing is com‐

pleted.

♦ Do not drive the vehicle with the connector unplugged from the

control unit.

♦ During the final road test ⇒ page 6 , ensure that an ABS-

controlled brake application is performed at least once

⇒ page 4 .

1.4 Requirements for test

• When starting the self-diagnosis procedure, the vehicle must

be stationary and the ignition switched on (or engine running). It is not possible to start self-diagnosis if the wheel speed is

4 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

above 2.75 km/h. Self-diagnosis will be terminated if road speed exceeds 20 km/h.

• Power supply OK (min. 10.0 V).

• Fuses OK ⇒ Current flow diagrams, Electrical fault finding and Fitting locations.

• Connector on ABS with EDL control unit -J104- correctly plug‐ ged-in (retainer is engaged).

• The tyres fitted to all wheels must be of the same (approved) size; tyres inflated to prescribed pressure.

• Wheel speed sensors must be installed correctly ⇒ Brake system; Rep. Gr. 45 .

• Mechanical/ hydraulic brake system components (including brake light switch and brake lights) OK. Hydraulic connections and pipes not leaking (visual check of hydraulic unit, brake calipers, wheel cylinders, master brake cylinder).

• Wheel bearings and wheel bearing play OK.

• When testing the ABS/EDL/TCS and ESP systems, ensure that the vehicle's electrics are not subjected to electromag‐ netic interference: keep the vehicle away from equipment with a high current draw, such as electric welding units.

Audi TT 1999 ➤

1.5 Fault finding procedure

If a problem exists on the vehicle, perform the fault-finding pro‐ cedure in the following sequence:

– First switch on the ignition and observe the warning lamps.

This will give an initial indication of what to look for (vehicles without ESP ⇒ page 14 , vehicles with ESP ⇒ page 62 ).

– Observe the test requirements detailed on ⇒ page 4 .

– Connect vehicle diagnostic, testing and information system -

VAS 5051 A- and select vehicle system “03 - Brake electron‐ ics” ⇒ page 7 .

– Check the control unit version ⇒ page 8 .

– Interrogate the fault memory (vehicles without ESP

⇒ page 17 , vehicles with ESP ⇒ page 65 ). If a fault is

present in the memory: print out the content of the fault mem‐ ory and then erase the fault memory.

– Conclude the transfer of data with the function “06 - End out‐

put”.

– Eliminate the fault using the fault tables.

– If a component is indicated as being defective, only renew it if

you are sure that the electrical wiring for that component is in proper condition. The wiring must be able to transmit the nec‐ essary signals without interference or resistance. Check the wiring for:

♦ Corrosion and loose contacts in the connectors and earth con‐

nections. If any of the plug contacts are bent, broken or cor‐ roded, use the wiring repair kit -VAS 1978- to fit new contacts.

♦ Open circuit in wiring or short circuit to positive/earth ⇒ Current

flow diagrams, Electrical fault finding and Fitting locations.

– Check that the connectors are plugged in correctly (with re‐

tainers engaged).

– After completing the repair, select vehicle system “03 - Brake

system” for a second time. Interrogate and erase fault mem‐ ory.

1. Self-diagnosis 5

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

– Conclude the transfer of data with the function “06 - End out‐

put”.

– Switch off ignition and detach diagnostic connector.

– Perform a road test ⇒ page 6 to check the function of the

system. If any of the warning lamps light up during the road test, repeat the fault finding procedure.

WARNING

If the connector is not plugged into the ABS with EDL control unit -J104- when the vehicle is moving, this may result in a spurious (non-existent) fault being registered in the fault mem‐ ory of another control unit. The function of the brake system will be impaired. The brake pressure at the rear wheels is no longer controlled by the electronic brake force distribution func‐ tion. This can result in excessive braking at the rear, and the tail of the vehicle may break out unexpectedly.

Note

For information on repairing common faults, refer to ⇒ Technical Service Handbook.

1.6 Road test

Certain faults will only be detected by the self-diagnosis when the vehicle is moving. Perform a road test to check the function of the system.

WARNING

♦ To avoid any risk of accident, observe the safety precau‐

tions when using test instruments while road testing the vehicle ⇒ “1.3 Safety precautions”, page 4 .

♦ If you drive the vehicle after a fault has been detected by

the self-diagnosis bear in mind that there is a risk of acci‐ dent. The function of the brake system will be impaired. The brake pressure at the rear wheels is no longer con‐ trolled by the electronic brake force distribution function. This can result in excessive braking at the rear, and the tail of the vehicle may break out unexpectedly.

♦ The ABS/ESP function is deactivated when using vehicle

diagnostic, testing and information system -VAS 5051 Ain the mode “vehicle self-diagnosis” while road testing the vehicle. However, this is not indicated by illumination of the warning lamps. Self-diagnosis of ABS with EDL control unit -J104- is terminated if a road speed of 20 km/h is ex‐ ceeded.

– Maintain a speed above 60 km/h for a period of 30 seconds.

After ensuring that it is safe to do so, apply the brakes hard enough to activate ABS-controlled braking. This can be felt from the pulsation at the brake pedal.

1.6.1 Special feature for four-wheel drive ve‐ hicles with Haldex coupling

♦ The longitudinal acceleration sender -G251- must be deacti‐

vated when testing the brake system on test rollers (vehicles without ESP ⇒ page 35 , vehicles with ESP ⇒ page 90 ).

6 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

♦ After completion of the check, the longitudinal acceleration

sender -G251- must be reactivated by switching the ignition off and back on again.

1.7 Connecting vehicle diagnostic, testing and information system -VAS 5051 A-

– With ignition switched off, connect vehicle diagnostic, testing

and information system -VAS 5051 A- with diagnosis lead VAS 5051 A/1- to diagnostic connection.

WARNING

Observe the relevant safety precautions ⇒ page 4 .

Note

Refer to ⇒ Operating instructions for vehicle diagnostic, testing and information system -VAS 5051 A- if a fault is indicated on the display.

Audi TT 1999 ➤

– Switch on ignition.

or

– Start engine.

Indicated on -VAS 5051 A- :

– Touch “Vehicle self-diagnosis” key.

Indicated on -VAS 5051 A- :

Note

Touching function “00 - Interrogate fault memory - complete sys‐ tem” in list -1- implements the automatic test sequence, i.e. fault memory interrogation takes place for all vehicle systems with selfdiagnosis capability.

– From menu -1- select vehicle system “03 - Brake electronics”.

– Wait until next readout appears.

1. Self-diagnosis 7

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

2 - Control unit identification of ABS with EDL control unit -J104- .

Control unit identification : ABS with EDL control unit -J104- (example)

03 - Brake

Vehicle system

electronics 8N0907379.. Part No.; Allocation ⇒ Parts catalogue ESP System designation CAN Data bus (CAN) Code number

241

Control unit code (checking: vehicles without ESP ⇒ page 39 , vehicles with ESP

⇒ page 103 ).

Dealership number 12345

Dealership identifier of -VAS 5051 A- with which coding was last performed

If the display “vehicle system not available” appears in display zone -1-:

– Check:

♦ Voltage supply to diagnosis connector ⇒ Current flow dia‐

grams, Electrical fault finding and Fitting locations.

♦ Wiring connection between diagnosis connector and ABS with

EDL control unit -J104- ⇒ Current flow diagrams, Electrical fault finding and Fitting locations.

8 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

2 CAN bus

Data bus:

A data bus is a system for the transmission and distribution of data signals.

CAN:

A Controller Area Network is a bus system working with two wires. They are referred to as bus wires. The bus wires transmit data signals in serial form (one after the other) to the control units con‐ nected to the system.

These control units communicate with each other (i.e. exchange data) via the CAN bus.

2.1 Testing a “two-wire data bus system”

Special tools and workshop equipment required

♦ Vehicle diagnostic, testing and information system -VAS 5051

A-

Test sequence:

– Refer to the appropriate current flow diagram to check how

many control units are connected to the CAN bus.

– Connect vehicle diagnostic, testing and information system -

VAS 5051 A- ⇒ page 7 and select function “00 - Automatic test sequence”. When doing this the ignition must be switched on.

– Before testing the data bus wires make sure that there are no

faults in any of the control units which are connected to the data bus. If a fault exists, the communication with other the control units is affected.

Note

Audi TT 1999 ➤

A fault existing in or related to one of the control units does not affect the data bus system directly, but results from a malfunction of some kind in one of the systems. This may be a defective sen‐ sor, for example. The result is that the sensor signal can no longer be processed for transmission via the data bus. A malfunction of this kind has an indirect effect on the data bus system, and will upset the communication with other control units which require the signal from the affected sensor.

Procedure if a fault exists:

– Rectify the fault first.

– Print out the list of faults and erase the fault memories of all

control units (refer to “Interrogating fault memory” and “Eras‐ ing fault memory” for the relevant control unit.

– Conclude the transfer of data with the function “06 - End out‐

put”.

– Rectify the faults as described in the fault tables in the relevant

Workshop Manual.

When all faults have been rectified:

– If communication between the control units is still not working

properly, test the data bus wires.

– Distinguish between two possible configurations when tracing

faults in the bus wires.

2. CAN bus 9

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

♦ Two control units communicating via a “Two-line bus system”

⇒ page 10 .

♦ Three or more control units communicating via a “Two-line bus

system” ⇒ page 11 .

2.1.1 Two control units communicating via a “Two-line bus system”.

– Switch off ignition.

– Unplug multi-pin connectors at both control units.

– Check for an open circuit in the bus wires ⇒ Current flow dia‐

grams, Electrical fault finding and Fitting locations.

– Check for short circuit between the bus wires ⇒ Current flow

diagrams, Electrical fault finding and Fitting locations.

– Check for short to positive and short to earth in the bus wires.

If the cause of the fault cannot be found in the data bus wires:

– As a trial measure, renew the control unit which can be ex‐

changed with the least effort in terms of time and cost.

If the control unit communication via data bus is still not OK:

– Renew the second control unit.

10 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

2.1.2 Three or more control units communi‐ cating via a “Two-line bus system”.

Example 1:

The faults stored in the fault memories indicate that the control unit -1- has no connection to control units -2- and -3-.

Control unit Faults stored in fault memory

-1- ♦ No message from control unit -2-

♦ No message from control unit -3-

-2- ♦ No message from control unit -1-

-3- ♦ No message from control unit -1-

– Switch off ignition.

– Unplug electrical connectors on control units linked by data

bus wires and check bus wires for open circuit ⇒ Current flow diagrams, Electrical fault finding and Fitting locations.

Audi TT 1999 ➤

Example 2:

The faults stored in the fault memories indicate that the control unit -2- does not communicate with control units -1- and -3-.

Control unit Faults stored in fault memory

-1- ♦ No message from control unit -2-

-2- ♦ No message from control unit -1-

♦ No message from control unit -3-

-3- ♦ No message from control unit -2-

– Switch off ignition.

– Unplug electrical connectors on control units linked by data

bus wires and check bus wires for open circuit ⇒ Current flow diagrams, Electrical fault finding and Fitting locations.

Example 3:

The faults stored in the fault memories indicate that none of the control units can transmit or receive.

Control unit Faults stored in fault memory

-1- ♦ Control unit defective

-2- ♦ Control unit defective

-3- ♦ Control unit defective

– Switch off ignition.

– Unplug electrical connectors on control units linked by data

bus wires and check bus wires for short circuit ⇒ Current flow diagrams, Electrical fault finding and Fitting locations.

2. CAN bus 11

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

– Check the bus wires for short to positive and short to earth.

– If the cause of the fault “Control unit defective” cannot be found

in the data bus wires, check whether one of the control units is responsible for causing the fault.

• Electrical connectors on all control unit that communicate via the CAN data bus are unplugged.

• Ignition switched off

– Connect one of the control units.

– Connect vehicle diagnostic, testing and information system -

VAS 5051 A- ⇒ page 7 .

– Switch on ignition and select the relevant vehicle system.

– Interrogate and erase the fault memory of the control unit

which has been just connected.

– Terminate function “05 - Erasing fault memory” by touching

← key.

– Conclude the transfer of data with the function “06 - End out‐

put”.

– Switch the ignition off and then on again.

– Leave the ignition switched on for 10 seconds. Then interrog‐

ate the fault memory of the control unit that has just been connected.

If the fault “control unit defective” is indicated:

– Renew the control unit which has just been connected.

If the fault “control unit defective” is not indicated:

– Connect the next control unit and repeat the procedure.

12 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

3 ABS/EDL and ABS/EDL/TCS, ITT

Mark 20 without ESP

♦ The Audi TT without ESP is equipped with the ABS/EDL ITT

Mark 20 system or the ABS/EDL/TCS ITT Mark 20 system.

♦ The data signals are transmitted via CAN bus.

Note

ESP may have been retrofitted by AUDI AG on vehicles not orig‐ inally equipped with this system ⇒ page 59 .

3.1 Electrical/electronic components and fitting locations

1 - Brake master cylinder and brake servo

2 - Hydraulic control unit

❑ The hydraulic control

unit comprises the ABS hydraulic pump -V64- , the ABS hydraulic unit N55- and the ABS with EDL control unit -J104- .

❑ Fitting location: in en‐

gine compartment (leftside)

❑ Tested by self-diagno‐

❑ Only unplug 25-pin con‐

❑ Assignment of 25-pin

❑ Removing and installing

❑ Perform coding of ABS

3 - Traction control system warning lamp -K86-

❑ Only on vehicles with

❑ Fitting location: in instru‐

❑ Function ⇒ page 14

4 - “Brake warning” symbol

❑ Appears in the display of

❑ Function ⇒ page 14

5 - ABS warning lamp -K47-

❑ Fitting location: in instrument cluster ❑ Function ⇒ page 14

sis

nector when the ignition is switched off

connector ⇒ page 50

⇒ Brake system; Rep. Gr. 45

with EDL control unit J104- after renewal

⇒ page 39

TCS

ment cluster

the driver information system

Audi TT 1999 ➤

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 13

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

6 - Rear left and rear right speed sensor and speed sensor rotor

❑ Rear left speed sensor -G46- and rear right speed sensor -G44❑ Removing and installing speed sensor, fitting speed sensor wires ⇒ Brake system; Rep. Gr. 45 ❑ Checking speed sensor rotor ⇒ Brake system; Rep. Gr. 45 ❑ Speed sensor rotor is welded to wheel hub; removing and installing wheel hub ⇒ Running gear, front-

wheel drive and four-wheel drive; Rep. Gr. 42

7 - Diagnosis connector

❑ Fitting location: in footwell (front left), next to release lever for bonnet.

8 - Diagnostics connection cover

9 - Brake light switch -F-

❑ Can be checked via reading measured value block ⇒ page 45 ❑ Removing and installing ⇒ Brake system; Rep. Gr. 45

10 - Front left and front right speed sensor and speed sensor rotor

❑ Front left speed sensor -G47- and front right speed sensor -G45❑ Removing and installing speed sensor, fitting speed sensor wires ⇒ Brake system; Rep. Gr. 45 ❑ Checking speed sensor rotor ⇒ Brake system; Rep. Gr. 45 ❑ Speed sensor rotor is welded to wheel hub; removing and installing wheel hub ⇒ Running gear, front-

wheel drive and four-wheel drive; Rep. Gr. 40

11 - Longitudinal acceleration sender -G251-

❑ Four-wheel drive vehicles only ❑ Fitting location: on A-pillar (passenger side) ❑ Can be checked via reading measured value block ⇒ page 46 ❑ Refer to ⇒ Brake system; Rep. Gr. 45 for removing and installing, then perform zero compensation in

basic setting ⇒ page 36

3.2 Faults displayed by warning lamps in in‐

strument cluster

1 - “Brake warning” symbol

2 - ABS warning lamp -K47-

3 - Handbrake warning lamp -K14-

4 - Traction control system warning lamp -K86- (only on vehi‐

cles with TCS)

“Brake warning”

symbol

On On On Test sequence after switching on ignition (first two sec‐

Off Off Off System OK (2 seconds after switching on ignition) Off Off On TCS system failure or TCS system has been switched

Off Off flashes TCS control function is operating Off On On ABS/EDL/TCS system failure (e.g. wheel speed sen‐

On On On ABS/EDL/TCS/EBPD system failure (e.g. several

ABS warning

lamp -K47-

Traction control system warning

lamp -K86-

1)

Explanation

onds).

off via button; ABS, EDL and EBPD systems remain functional.

sor defective), the EBPD remains fully functional.

wheel speed sensors defective)

14 Rep. Gr.01 - Self-diagnosis, electrical checks

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Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

“Brake warning”

symbol

ABS warning

lamp -K47-

Traction control system warning

lamp -K86-

1)

Explanation

On Off Off Brake fluid level too low; all systems remain functional

1) Only on vehicles with TCS system

WARNING

There is a risk of accident if the ABS warning lamp -K47- and the “brake warning symbol” both light up. The function of the brake system will be impaired. As the brake pressure is no longer controlled by the electronic brake force distribution the rear wheels tend to brake excessively. Due to this the rear of the vehicle may break away unexpectedly.

The ABS warning lamp -K47- -item 2- lights up during the test sequence (self-test)

The system runs through an automatic test sequence when the ignition is switched on: the ABS warning lamp -K47- is activated by the ABS with EDL control unit -J104- and lights up for 2 sec‐ onds. During this period the control unit tests the following func‐ tions via self-test.

♦ The voltage supply is checked (min. 10.0 Volt).

♦ The control unit including the valve windings is checked.

♦ A speed sensor check (electrical test) is carried out; this is only

completed at 20 km/h.

♦ Control unit code is checked.

If the system does not perform the test sequence:

– Check voltage supply of ABS with EDL control unit -J104-

(perform electrical check, step 3 ⇒ page 51 ).

The ABS warning lamp -K47- -item 2- stays on after the test se‐ quence is completed

If a fault affecting only the anti-lock brake system is detected by self-diagnosis, the ABS is switched off. The conventional brake system remains fully functional.

The causes of the fault may be as follows:

♦ Voltage supply is below 10 Volts.

♦ A fault exists which affects only the ABS.

♦ A sensor fault has occurred after the last start (sporadic fault).

In this case the ABS warning lamp goes out automatically after the vehicle is started again and the road speed exceeds 20 km/ h.

♦ Connection between ABS with EDL control unit -J104- and in‐

strument cluster is faulty or instrument cluster faulty (perform electrical check, step 14 ⇒ page 55 ).

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 15

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

The ABS warning lamp -K47- -item 2- goes out after the test se‐ quence is completed,, but “brake warning symbol” -1- remains on

All systems remain functional.

The causes of the fault may be as follows:

♦ Brake fluid level too low.

♦ Fault in instrument cluster ⇒ Electrical system, self-diagnosis;

Rep. Gr. 01 or ⇒ Current flow diagrams, Electrical fault finding and Fitting locations.

The ABS warning lamp -K47- -item 2- stays on after the test se‐ quence is completed and “brake warning symbol” -1- lights up when vehicle speed first exceeds 10 km/h or engine speed first exceeds 2000 rpm

The ABS system is defective and the EBPD system deactivated.

WARNING

There is a risk of accident if the ABS warning lamp -K47- and the “brake warning symbol” both light up.The function of the brake system will be impaired. As the brake pressure is no longer controlled by the electronic brake force distribution the rear wheels tend to brake excessively.Due to this the rear of the vehicle may break away unexpectedly.

The causes of the fault may be as follows:

♦ The control unit is not coded (Code 00000), or is incorrectly

coded. In this case the ABS warning lamp -K47- will flash at a rate of once per second. The “brake warning” symbol will also flash when vehicle speed first exceeds 10 km/h or engine speed first exceeds 2000 rpm after the ignition is switched on.

♦ A fault exists which affects the ABS and EBPD.

Note

If the ABS warning lamp -K47- and the “brake warning” symbol do not light up but the brake system is not fully functional, the fault must be traced in the conventional brake system ⇒ Brake system; Rep. Gr. 46 and ⇒ Brake system; Rep. Gr. 47 .

Traction control system warning lamp -K86- -item 1- does not light up after TCS is deactivated by pressing the traction control sys‐ tem switch -E132- -item 2-.

The causes of the fault may be as follows:

♦ Traction control system warning lamp -K86- defective (perform

electrical check, step 17 ⇒ page 57 ).

♦ Traction control system switch -E132- defective (perform elec‐

trical check, step 17 ⇒ page 57 and step 18 ⇒ page 57 ).

♦ Open circuit in vehicle power supply and wiring from ABS with

EDL control unit -J104- to instrument cluster (perform electri‐ cal check, step 17 ⇒ page 57 and step 18 ⇒ page 57 .

♦ Short circuit to positive in wiring from ABS with EDL control

unit -J104- to instrument cluster (perform electrical check, step 17 ⇒ page 57 and step 18 ⇒ page 57 ).

16 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

Traction control system warning lamp -K86- lights continuously after ignition is switched on, and none of the malfunctions above occur

The cause of the fault may be as follows:

♦ Short circuit to earth in wiring from ABS with EDL control unit

-J104- to instrument cluster (activation of TCS warning lamp) (perform electrical check, step 17 ⇒ page 57 and step 18

⇒ page 57 ).

Vehicle with ABS/EDL has no EDL function

A possible cause of this fault is that the brake light switch is not functioning. Check “measured value block 003” ⇒ page 45 . Renewing brake light switch ⇒ Brake system; Rep. Gr. 45 .

3.3 Performing self-diagnosis on the ABS/ EDL and ABS/EDL/TCS, ITT Mark 20 without ESP

List of available functions

– With ignition switched off, connect vehicle diagnostic, testing

and information system -VAS 5051 A- with diagnosis lead VAS 5051 A/1- to diagnosis connector and select vehicle system “03 - Brake electronics” ⇒ page 7 .

The following functions are available from the list -1-:

Audi TT 1999 ➤

Functions Page

02 Interrogate fault memory ⇒ page 17 03 Final control diagnosis ⇒ page 25 04 Basic setting ⇒ page 32 05 Erase fault memory ⇒ page 38 06 End output ⇒ page 39 07 Code control unit ⇒ page 39 08 Read measured value block ⇒ page 42 11

Login procedure/encoding II

2) The login procedure/encoding II is only required on four-wheel drive vehicles.

2)

⇒ page 46

The other functions displayed are currently not available, or can be disregarded.

3.4 Interrogating fault memory

– Connect vehicle diagnostic, testing and information system -

VAS 5051 A- ⇒ page 7 and select vehicle system “03 - Brake electronics”. When doing this the ignition must be switched on.

Indicated on -VAS 5051 A- :

– From list -1- select function “02 - Interrogate fault memory”.

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 17

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

-1- Content of fault memory No faults detected or X faults detected

-2- Fault Fault code Fault location Type of fault

A - If a fault was detected:

– Print out information on screen or self-diagnosis log.

– Terminate function “02 - Interrogate fault memory” by touching

← key.

Indicated on -VAS 5051 A- :

– Rectify fault(s) according to fault tables ⇒ page 18 .

– From list -1- select function “02 - Interrogate fault memory” and

erase fault memory ⇒ page 38 .

– From list -1- select function “06 - End output” ⇒ page 39 .

– Perform road test and interrogate fault memory again.

B - If no fault was detected:

– Terminate function “02 - Interrogate fault memory” by touching

← key.

– Select function “06 - End output” from list ⇒ page 39 .

3.5 Fault tables

Note

♦

The following table includes all faults which can be detected by the ABS with EDL control unit -J104- and displayed by VAS 5051 A- when interrogating the fault memory.

♦

The contents of the fault memory remains stored until the memory is erased; Erasing fault memory ⇒ page 38 .

♦

Faults are listed according to a 5-digit fault code, which ap‐ pears in the left-hand column of the fault table.

♦

Sporadic (intermittent) faults are identified as such by the word “sporadic” appearing on the display.

♦

Check wiring and connectors going to the relevant compo‐ nents according to current flow diagram before renewing com‐ ponents indicated as faulty by -VAS 5051 A- . Also check earth connections according to current flow diagram. This is partic‐ ularly important if faults are indicated as being “sporadic”.

Fault 00283

Display on -

VAS 5051 A-

00283 Front left speed sensor -G47-

♦ Open circuit, loose contact or short to

Possible cause of fault Fault remedy

positive or earth in speed sensor wire or speed sensor

– Perform electrical check, step 6

⇒ page 52 and step 10 ⇒ page 54

♦ Speed sensor winding defective

18 Rep. Gr.01 - Self-diagnosis, electrical checks

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Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

Display on -

VAS 5051 A-

♦ Speed sensor or rotor damaged – Check speed sensor and rotor ⇒ Brake

♦ ABS with EDL control unit -J104- defec‐

tive

00283 Front left speed sensor -G47Mechanical fault

• This fault is only detec‐

♦ Excessive air gap between speed sensor

and rotor. ted above 20 km/h (carry out test drive).

♦ Outlet valves in hydraulic unit defective – Check hydraulic unit in final control diag‐

00283 Front left speed sensor -G47Signal outside tolerance

• This fault is only detec‐ ted above 20 km/h (carry out test

♦ Open circuit, loose contact or short to

positive or earth in speed sensor wire or speed sensor

♦ Speed sensor winding defective

drive).

♦ Electrical interference from external in‐

terference sources (high frequency radi‐ ation, e.g. non-insulated ignition cable)

Possible cause of fault Fault remedy

system; Rep. Gr. 45

– Remove hydraulic control unit, renew

control unit ⇒ Brake system; Rep. Gr. 45 , then code control unit ⇒ page 39

– Check installation of speed sensor and

rotor ⇒ Brake system; Rep. Gr. 45

nosis ⇒ page 25

– Perform electrical check, step 6

⇒ page 52 and step 10 ⇒ page 54

– Read measured value block 001

⇒ page 44

♦ Excessive air gap between speed sensor

and rotor.

♦ Speed sensor or rotor damaged – Check speed sensor and rotor ⇒ Brake

Fault 00285

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

00285 Front right speed sensor -G45-

♦ Open circuit, loose contact or short to

positive or earth in speed sensor wire or speed sensor

♦ Speed sensor winding defective

♦ Speed sensor or rotor damaged – Check speed sensor and rotor ⇒ Brake

♦ ABS with EDL control unit -J104- defec‐

tive

00285 Front right speed sensor -G45Mechanical fault

– Check installation of speed sensor and

rotor ⇒ Brake system; Rep. Gr. 45

system; Rep. Gr. 45

– Perform electrical check, step 5

⇒ page 52 and step 9 ⇒ page 54

system; Rep. Gr. 45

– Remove hydraulic control unit, renew

control unit ⇒ Brake system; Rep. Gr. 45 , then code control unit ⇒ page 39

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 19

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

• This fault is only detec‐

♦ Excessive air gap between speed sensor

and rotor. ted above 20 km/h (carry out test drive).

♦ Outlet valves in hydraulic unit defective – Check hydraulic unit in final control diag‐

00285 Front right speed sensor -G45Signal outside tolerance

• This fault is only detec‐ ted above 20 km/h (carry out test

♦ Open circuit, loose contact or short to

positive or earth in speed sensor wire or speed sensor

♦ Speed sensor winding defective

drive).

♦ Electrical interference from external in‐

terference sources (high frequency radi‐ ation, e.g. non-insulated ignition cable)

♦ Excessive air gap between speed sensor

and rotor.

– Check installation of speed sensor and

rotor ⇒ Brake system; Rep. Gr. 45

nosis ⇒ page 25

– Perform electrical check, step 5

⇒ page 52 and step 9 ⇒ page 54

– Read measured value block 001

⇒ page 44

– Check installation of speed sensor and

rotor ⇒ Brake system; Rep. Gr. 45

♦ Speed sensor or rotor damaged – Check speed sensor and rotor ⇒ Brake

Fault 00287

Display on -

VAS 5051 A-

00287 Rear right speed sensor -G44-

♦ Open circuit, loose contact or short to

positive or earth in speed sensor wire or speed sensor

♦ Speed sensor winding defective

♦ Speed sensor or rotor damaged – Check speed sensor and rotor ⇒ Brake

♦ ABS with EDL control unit -J104- defec‐

tive

00287 Rear right speed sensor -G44Mechanical fault

• This fault is only detec‐

♦ Excessive air gap between speed sensor

and rotor. ted above 20 km/h (carry out test drive).

system; Rep. Gr. 45

Possible cause of fault Fault remedy

– Perform electrical check, step 7

⇒ page 53 and step 11 ⇒ page 54

system; Rep. Gr. 45

– Remove hydraulic control unit, renew

control unit ⇒ Brake system; Rep. Gr. 45 , then code control unit ⇒ page 39

– Check installation of speed sensor and

rotor ⇒ Brake system; Rep. Gr. 45

♦ Outlet valves in hydraulic unit defective – Check hydraulic unit in final control diag‐

00287 Rear right speed sensor -G44Signal outside tolerance

20 Rep. Gr.01 - Self-diagnosis, electrical checks

nosis ⇒ page 25

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Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

Display on -

VAS 5051 A-

• This fault is only detec‐ ted above 20 km/h (carry out test

♦ Open circuit, loose contact or short to

positive or earth in speed sensor wire or speed sensor

♦ Speed sensor winding defective

drive).

♦ Electrical interference from external in‐

terference sources (high frequency radi‐ ation, e.g. non-insulated ignition cable)

♦ Excessive air gap between speed sensor

and rotor.

♦ Speed sensor or rotor damaged – Check speed sensor and rotor ⇒ Brake

Fault 00290

Display on -

VAS 5051 A-

00290 Rear left speed sensor -G46-

♦ Open circuit, loose contact or short to

positive or earth in speed sensor wire or speed sensor

♦ Speed sensor winding defective

♦ Speed sensor or rotor damaged – Check speed sensor and rotor ⇒ Brake

♦ ABS with EDL control unit -J104- defec‐

tive

00290 Rear left speed sensor -G46Mechanical fault

• This fault is only detec‐

♦ Excessive air gap between speed sensor

and rotor. ted above 20 km/h (carry out test drive).

Possible cause of fault Fault remedy

– Perform electrical check, step 7

⇒ page 53 and step 11 ⇒ page 54

– Read measured value block 001

⇒ page 44

– Check installation of speed sensor and

rotor ⇒ Brake system; Rep. Gr. 45

system; Rep. Gr. 45

Possible cause of fault Fault remedy

– Perform electrical check, step 8

⇒ page 53 and step 12 ⇒ page 55

system; Rep. Gr. 45

– Remove hydraulic control unit, renew

control unit ⇒ Brake system; Rep. Gr. 45 , then code control unit ⇒ page 39

– Check installation of speed sensor and

rotor ⇒ Brake system; Rep. Gr. 45

♦ Outlet valves in hydraulic unit defective – Check hydraulic unit in final control diag‐

♦ Excessive air gap between speed sensor

and rotor.

00290 Rear left speed sensor -G46Signal outside tolerance

• This fault is only detec‐ ted above 20 km/h (carry out test

♦ Open circuit, loose contact or short to

positive or earth in speed sensor wire or speed sensor

♦ Speed sensor winding defective

drive).

nosis ⇒ page 25

– Check installation of speed sensor and

rotor ⇒ Brake system; Rep. Gr. 45

– Perform electrical check, step 8

⇒ page 53 and step 12 ⇒ page 55

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 21

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Display on -

VAS 5051 A-

♦ Electrical interference from external in‐

terference sources (high frequency radi‐ ation, e.g. non-insulated ignition cable)

♦ Excessive air gap between speed sensor

and rotor.

♦ Speed sensor or rotor damaged – Check speed sensor and rotor ⇒ Brake

Fault 00668

Display on -

VAS 5051 A-

00668 Vehicle voltage, terminal 30 Signal outside tolerance

♦ Fuse defective

♦ Open circuit or short circuit to earth or

positive in voltage supply wiring

Possible cause of fault Fault remedy

– Read measured value block 001

⇒ page 44

– Check installation of speed sensor and

rotor ⇒ Brake system; Rep. Gr. 45

system; Rep. Gr. 45

Possible cause of fault Fault remedy

– Perform electrical check, step 1

⇒ page 51 and step 2 ⇒ page 51

Fault 01044

Display on -

VAS 5051 A-

01044 Control unit incorrectly coded

♦ An incorrect code number has been en‐

tered

♦ Coding bridge in wiring harness dam‐

aged

Fault 01130

Display on -

VAS 5051 A-

01130 ABS operation Signal outside tolerance

• This fault is only detec‐ ted above 20 km/h (carry out test drive).

♦ Electrical interference from external in‐

terference sources (high frequency radi‐ ation, e.g. non-insulated ignition cable)

♦ Open circuit, loose contact or short to

positive or earth in wiring

Possible cause of fault Fault remedy

– Check code ⇒ page 39

– Check wires in wiring harness; perform

electrical check, test step 13

⇒ page 55

Possible cause of fault Fault remedy

– Check all wiring and connections for

short to positive or earth.

– Erase fault memory

– Perform test drive at more than 20 km/h

22 Rep. Gr.01 - Self-diagnosis, electrical checks

– Interrogate fault memory again

If the fault is not rectified: – Remove hydraulic control unit, renew

control unit ⇒ Brake system; Rep. Gr. 45 , then code control unit ⇒ page 39

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Fault 01276

Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

01276 ABS hydraulic pump -V64Signal outside tolerance

• This fault is only detec‐ ted above 20 km/h (carry

♦ Open circuit or short circuit to earth or

positive in internal wiring: ABS with EDL control unit -J104- / ABS hydraulic pump

-V64out test drive).

♦ ABS with EDL control unit -J104- defec‐

tive

♦ Pump motor defective – Renew hydraulic control unit ⇒ Brake

Fault 01279

Display on -

VAS 5051 A-

01279 Longitudinal acceleration sender -G251-

Possible cause of fault Fault remedy

3)

Electrical fault in circuit

♦ Open circuit, loose contact or short to

positive or earth in wiring

– Check ABS hydraulic pump -V64- via fi‐

nal control diagnosis ⇒ page 25

If ABS hydraulic pump -V64- starts running during final control diagnosis: – Perform electrical check, test step 1

⇒ page 51

– Check all wiring and connections for

short to positive or earth according to cur‐ rent flow diagram.

– Remove hydraulic control unit, renew

control unit ⇒ Brake system; Rep. Gr. 45 , then code control unit ⇒ page 39

system; Rep. Gr. 45

– Perform electrical check, test step 19

⇒ page 58

♦ Installation position of longitudinal accel‐

eration sender -G251- not OK

♦ Longitudinal acceleration sender -G251-

defective

3) Four-wheel drive vehicles only.

Fault 01312

Display on -

VAS 5051 A-

01312 Drive train data bus defective

4)

♦ ABS with EDL control unit -J104- incor‐

rectly coded

♦ Engine control unit incorrectly coded – Check coding of engine control unit ⇒

– Check installation position ⇒ Brake sys‐

tem; Rep. Gr. 45

– Read measured value block 006

⇒ page 46

– Renew sender ⇒ Brake system; Rep. Gr.

45 , then perform zero compensation in basic setting ⇒ page 36

Possible cause of fault Fault remedy

– Check code ⇒ page 39

Motronic injection and ignition system; Rep. Gr. 01

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 23

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

4) If fault is displayed as sporadic fault: can occur when vehicle is started. This is not a fault in the system; ignore and erase fault memory.

♦ Faults in CAN bus wiring – Check CAN bus wiring between engine

Fault 01314

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

01314 Engine control unit No communication

• Signals are transmitted between

5)

When displayed as static fault: ♦ ABS with EDL control unit -J104- or en‐

gine control unit not CAN compatible ABS with EDL control unit -J104and engine

♦ Fault in engine control unit – Interrogate fault memory of engine con‐

control unit via CAN data bus

When displayed as static and sporadic fault: ♦ Faults in CAN bus wiring

♦ High and Low CAN bus wiring inter‐

changed

♦ The output of one of the control units

communicating via the CAN bus is de‐

fective.

control unit and ABS with EDL control unit

-J104- ⇒ page 9

– Refer to control unit identification of ABS

with EDL control unit -J104- ⇒ page 8 and engine control unit to check that correct control units are installed. Allocation ⇒ Parts catalogue

trol unit ⇒ Motronic injection and ignition system; Rep. Gr. 01 , rectify fault if nec‐ essary and erase fault memory

– Check CAN bus wiring between engine

control unit and ABS with EDL control unit

-J104- ⇒ page 9

– Check CAN Bus wiring for interchanged

connections according to current flow di‐ agram

– Check CAN bus wiring ⇒ page 9

5) Only on vehicles with TCS system

Fault 01324

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

01324 Four-wheel drive control unit -J492No communication

6) Four-wheel drive vehicles only.

6)

♦ Faults in CAN bus wiring – Check CAN bus wiring ⇒ page 9

Fault 65535

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

65535 Control unit defective

24 Rep. Gr.01 - Self-diagnosis, electrical checks

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Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

♦ ABS with EDL control unit -J104- defec‐

tive

3.6 Final control diagnosis

The final control diagnosis can be used to check the ABS hy‐ draulic pump -V64- and the correct functioning of the hydraulic circuits (allocation of brake pipes to wheel brakes and function of valves). This function will also detect interchanged connections and leaks.

Note

♦

The vehicle must be raised until all wheels are free to turn.

♦

To avoid overloading the control elements they are only acti‐ vated for a period of 60 or 90 seconds. The final control test will be terminated if the → key is not pressed within this period.

– Remove hydraulic control unit, renew

control unit ⇒ Brake system; Rep. Gr. 45 , then code control unit ⇒ page 39

Do not erase the fault memory of the defec‐ tive control unit. The data in the fault memory will help to identify the malfunction

♦

The ABS warning lamp -K47- and the red “brake warning” symbol flash during the final control diagnosis.

♦

After depressing the brake pedal several times the vacuum in the brake servo will be exhausted. Therefore more pressure must be applied to the brake pedal in order to attain the same fluid pressure in the brake system as that attained with vac‐ uum.

♦

When vacuum in brake servo is exhausted it can happen that the wheels do not lock: start engine and build up vacuum in brake servo.

Meaning of abbreviations indicated on display

IFL = Inlet valve

OFL = Outlet valve

VBAT = Battery voltage; voltage at valve

0V = 0 Volt; No voltage at valve

Hydr-P = ABS hydraulic pump -V64-

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 25

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Components of the ABS/EDL system

The hydraulic circuit is a schematic diagram of the ABS/EDL sys‐ tem. The diagram shows only one brake circuit.

1 - Low pressure accumulator

2 - ABS hydraulic pump -V64-

3 - EDL inlet valve (hydraulic)

4 - Noise damping chamber

5 - EDL change-over/separating valve (electrical) with integra‐

ted pressure limiting valve

6 - Front inlet valve

7 - Front outlet valve

8 - Front wheel

9 - Rear inlet valve

10 - Rear outlet valve

11 - Rear wheel

Test condition

• The wheels are locked individually during final control diagno‐ sis. For this test the mechanical and hydraulic components of the brake system must be working properly. This means that the master cylinder is able to build up pressure in all four wheel brake cylinders and there are no leaks in the hydraulic pipes, hoses and connections.

Note

If one of the wheels does not lock, perform a visual inspection of the brake fluid reservoir, the master cylinder, the hydraulic unit and the wheel cylinders.

Procedure

– Connect vehicle diagnostic, testing and information system -

VAS 5051 A- ⇒ page 7 and select vehicle system “03 - Brake electronics”. When doing this the ignition must be switched on.

Indicated on -VAS 5051 A- :

– Release handbrake.

– Raise vehicle on lifting platform.

– From list -1- select function “03 - Final control diagnosis”.

26 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

A - Final control test waiting, move on to next control element

1 - ABS hydraulic pump V64

– Touch → key.

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

1 - ABS hydraulic pump V64

• The ABS hydraulic pump -V64- - item 2- should start up audi‐ bly.

Note

♦

When you put your foot on the brake pedal you can feel it vi‐ brating. This is because the hydraulic pump -V64- is producing pressure pulses in the brake pipes. The pressure pulses in‐ duce the vibrations that can be felt at the brake pedal.

♦

The pressure pulses in the brake pipes are not sufficient to lock the wheels.

Audi TT 1999 ➤

– Touch → key.

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

2 - Operate brakes

– Depress brake pedal and and touch → within 10 seconds.

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

3 - IFL: 0V OFL: 0V Wheel FL locked

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 27

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

• Brake pedal must not give.

• When you press the brake pedal, brake fluid pressure will be built up in all four wheel brake cylinders.

• The hydraulic EDL valve -3- closes, the front wheels -8- and rear wheels -11- are locked.

Note

This test step in the final control diagnosis corresponds to the“pressure build-up” phase during ABS-controlled braking.

– Touch → key.

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

4 - IFL: VBAT OFL: 0V Wheel FL locked

– Keep pressing the brake pedal.

• The hydraulic EDL valve -3- remains closed.

• The front inlet valve -6- is activated, which interrupts the supply to the wheel brake cylinder; however, the fluid pressure is still maintained in the wheel cylinder.

• The front left wheel -8- remains locked.

Note

This test step in the final control diagnosis corresponds to the“maintain pressure” phase during ABS-controlled braking.

– Touch → key.

28 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

5 - IFL: VBAT OFL: VBAT Wheel FL free to turn

– Keep pressing the brake pedal.

• The inlet valve -6- and the outlet valve -7- for the front left wheel -8- are activated.

• The ABS hydraulic pump -V64- -item 2- starts running and re‐ duces the brake fluid pressure in the wheel brake cylinder via the open outlet valve.

• The brake pedal must not give, and should press back harder against your foot.

• The front left wheel -8- is free to turn.

Audi TT 1999 ➤

Note

♦

This test step in the final control diagnosis corresponds to the“pressure reduction” phase during ABS-controlled braking.

♦

If you cannot turn the front left wheel, check whether the brake line for the front left wheel is correctly connected.

♦

If this is the case, this indicates that there is a mechanical fault in one of the valves, providing that there is no electrical fault in the system. Renew the hydraulic control unit ⇒ Brake sys‐ tem; Rep. Gr. 45 .

♦

If the brake pedal gives under your foot, this means that the inlet valve or the non-return valve connected in parallel with the inlet valve is leaking. Renew the hydraulic control unit ⇒ Brake system; Rep. Gr. 45 .

– Touch → key within the next 10 seconds.

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

6 - IFL: VBAT OFL: 0V Wheel FL free

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 29

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

– Keep pressing the brake pedal.

• The hydraulic EDL valve -3- remains closed.

• The ABS hydraulic pump -V64- - item 2- should stop running.

• Only the inlet valve -6- is now activated, and this interrupts the supply to the wheel brake cylinder.

• The front left wheel -8- is free to turn.

Note

If the wheel is not free to turn, this means that the inlet valve or the non-return valve connected in parallel with the inlet valve is leaking. Renew the hydraulic control unit ⇒ Brake system; Rep. Gr. 45 .

– Touch → key.

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

7 - IFL: 0V OFL: 0V Wheel FL locked

– Keep pressing the brake pedal.

• The inlet valve -6- is no longer activated and does not interrupt the supply to the wheel brake cylinder.

• Brake pedal will give perceptibly under your foot.

• Brake fluid pressure is built up again in the front left wheel cylinder -8- - the wheel is locked.

– Touch → key.

30 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

8 - Release brakes

– Release brake pedal.

– Touch → key.

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

9 - Operate brakes

Note

♦

Continue the final control diagnosis to check the front right, rear left and rear right wheels in turn.

♦

The test steps are the same as for the front left wheel, so they are not described in detail.

Audi TT 1999 ➤

After testing on rear right wheel is completed:

– Touch → key.

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

30 - EDL valves/Hyd-P: VBAT FL/FR wheel locked

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 31

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

• The EDL change-over valve -5- and the EDL inlet valve -3- are activated.

• The ABS hydraulic pump -V64- - item 2- should start running for one second. The pump draws brake fluid out of fluid res‐ ervoir via EDL inlet valve.

• The hydraulic pump builds up brake fluid pressure in the EDL controlled wheel brake cylinders. The front left and front right wheels -8- are locked.

Note

If the front wheels are not locked, this indicates that there is a mechanical fault in one of the valves, providing that there is no electrical fault in the system. Renew the hydraulic control unit ⇒ Brake system; Rep. Gr. 45 .

– Touch → key.

Indicated on -VAS 5051 A- :

A - Final control diagnosis competed

– Terminate function “03 - Final control diagnosis” by pressing

the ← key.

• Final control diagnosis is completed. The ABS warning lamp

-K47- and the red “brake warning” symbol should go out.

Note

♦

There is a fault in the system if the ABS warning lamp -K47does not go out.

♦

Adhere exactly to the test sequence: First interrogate fault memory, then erase.

3.7 Basic setting

The function “04 - Basic setting” can be used to perform the fol‐ lowing procedures:

♦ Bleeding brake system via display group 001 ⇒ page 32 if

brake fluid reservoir has been completely emptied. Basic set‐ ting is only necessary if one or more of the chambers in the brake fluid reservoir has been completely emptied (e.g. leaks in brake system).

♦ Only four-wheel drive vehicles: switching off longitudinal ac‐

celeration sender -G251- via display group 040 ⇒ page 35 (e.g. to check the brake system on test rollers).

♦ Only four-wheel drive vehicles: performing zero compensation

of longitudinal acceleration sender -G251- in display group 069 ⇒ page 36 (e.g. after renewing the following compo‐ nents: ABS with EDL control unit -J104- or longitudinal accel‐ eration sender -G251- ).

3.7.1 Bleeding brake system if brake fluid res‐

ervoir has run dry

Basic setting is only necessary if one or more of the chambers in the brake fluid reservoir has been completely emptied (e.g. leaks in brake system).

32 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

Special tools and workshop equipment required

♦ Brake charge and bleed equipment -VAS 5234- or upgrade kit

and extraction unit -V.A.G 1869 A-

Caution

♦ When using brake charge and bleed equipment -VAS

5234- to replenish the brake fluid, make sure that filling pressure does not exceed 1 bar.

♦ If the filling pressure exceeds 1 bar, a hydraulically con‐

trolled change-over valve for the EDL function prevents unrestricted flushing of the EDL-related parts of the hy‐ draulic unit. Proper bleeding is then no longer ensured.

♦ For this reason the brake fluid pressure must be reduced

to 1 bar on the brake charge and bleed equipment ⇒ Op‐ erating Manual -VAS 5234- or -V.A.G 1869 A-

♦ The charge and bleeder unit -V.A.G 1238/B- is not suitable

for bleeding the brake system by using the function “04 Basic setting”.

Audi TT 1999 ➤

Note

If only charge and bleeder unit -V.A.G 1238/B- is available, switch the unit on and off as necessary to ensure that sufficient brake fluid is always present in the reservoir.

Procedure

– Connect vehicle diagnostic, testing and information system -

VAS 5051 A- ⇒ page 7 and select vehicle system “03 - Brake electronics”. When doing this the ignition must be switched on.

– Connect the brake charge and bleed equipment -VAS 5234-

or -V.A.G 1869 A- .

– Open bleed screws in prescribed sequence and pre-bleed

brake calipers.

1 - Simultaneously bleed both front left and front right brake cali‐ per

2 - Simultaneously bleed both rear left and rear right brake caliper

– With bleeder bottle hoses attached, leave bleed screws open

until the brake fluid emerges free from bubbles.

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 33

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Bleeding

Indicated on -VAS 5051 A- :

– From list -1-, select function “04 - Basic setting”.

Indicated on -VAS 5051 A- :

1 - Enter display group

– Use keypad -2- to enter “001” for “Display group number 001”

and confirm by pressing the Q key.

• The ABS warning lamp -K47- flashes.

Indicated on -VAS 5051 A- :

1 - Basic setting

2 - Display group 1

3 - Press and hold pedal ...

– Press pedal with substantial foot pressure and hold.

• Pedal moves down, hydraulic pump starts up briefly, pedal comes back

Indicated on -VAS 5051 A- :

1 - Release pedal; FR/FL bleeder screws OPEN <>

– Release pedal, open front bleed screws.

– Press ↑ key to switch to display group 002.

Indicated on -VAS 5051 A- :

1 - Basic setting

2 - Display group 2

3 - Please wait ... (10 secs.)

– Wait 10 seconds.

• Hydraulic pump starts up briefly

Indicated on -VAS 5051 A- :

1 - Press pedal 10X; bleed screws CLOSED <>

– Press pedal 10 times, close front bleed screws.

– Press ↑ key to switch to display group 003.

34 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

1 - Basic setting

2 - Display group 3

3 - Press and hold pedal ...

– Repeat bleeding procedure as described above.

– Press the ↑ key in each case to switch to next highest display

group until display group 017 is reached.

Indicated on -VAS 5051 A- :

1 - Basic setting

2 - Display group 17

3 - Part bleeding ended ...

– Terminate function “04 - Basic setting” by pressing the ← key.

– The brake system must now be bled ⇒ Brake system; Rep.

Gr. 47 .

Audi TT 1999 ➤

3.7.2 Switching off longitudinal acceleration sender -G251- (only vehicles with fourwheel drive)

♦ The longitudinal acceleration sender -G251- must be switched

off in display group 040 when checking the brake system of a four-wheel drive vehicle on test rollers.

♦ After completion of the check, the longitudinal acceleration

sender -G251- must be reactivated by switching the ignition off and back on again.

Procedure

– Connect vehicle diagnostic, testing and information system -

VAS 5051 A- ⇒ page 7 and select vehicle system “03 - Brake electronics”. When doing this the ignition must be switched on.

Indicated on -VAS 5051 A- :

– From list -1-, select function “04 - Basic setting”.

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 35

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

1 - Enter display group

– Use keypad -2- to enter “040” for “display group number 040”

and confirm by pressing the Q key.

Indicated on -VAS 5051 A- :

A - Basic setting

B - Display group 40

• The ABS warning lamp -K47- flashes.

The longitudinal acceleration sender -G251- is now deactivated.

– Terminate function “04 - Basic setting” by pressing the ← key.

– Select function “06 - End output” from list.

– After completion of the check, the longitudinal acceleration

sender -G251- must be reactivated by switching the ignition off and back on again.

3.7.3 Performing zero compensation of longi‐ tudinal acceleration sender -G251- (only vehicles with four-wheel drive)

Zero compensation must be performed if the ABS with EDL con‐ trol unit -J104- or the longitudinal acceleration sender -G251were renewed, or if required by the fault table.

• Vehicle is standing horizontal on a flat base.

– Connect vehicle diagnostic, testing and information system -

VAS 5051 A- ⇒ page 7 and select vehicle system “03 - Brake electronics”. When doing this the ignition must be switched on.

Indicated on -VAS 5051 A- :

– From list -1- select diagnostic function “11 - Login procedure”

or “11 - Coding II”.

36 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

1 - Enter code word

– Use keypad -2- to enter code “40168” and confirm entry by

touching Q key.

Note

If display on -VAS 5051 A- reads “function unknown or function can not be performed at present” the login procedure or coding II were not successful. Repeat login procedure or coding II.

– Terminate function “11 - Login procedure” or “11 - Coding II”

by touching ← key.

Indicated on -VAS 5051 A- :

– From list -1-, select function “04 - Basic setting”.

Audi TT 1999 ➤

Indicated on -VAS 5051 A- :

1 - Enter display group

– Use keypad -2- to enter “069” for “display group number 069”

and confirm by pressing the Q key.

• The ABS warning lamp -K47- flashes.

Indicated on -VAS 5051 A- :

A - Basic setting

B - Display group 69

1 - Zero compensation OK

4 - 0.3 m/s

2

Zero compensation of longitudinal acceleration sender -G251- is now completed.

Note

The display does not return to 0.00 m/s2 after performing zero compensation successfully.

– Terminate function “04 - Basic setting” by pressing the ← key.

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 37

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Possible fault messages:

Indicated on -VAS 5051 A- :

1 - Zero compensation is not possible

4 - 5.0 m/s

2

The determined value is outside the tolerance range for zero compensation.

– Proceed as follows to rectify the fault:

1. Check zero position of longitudinal acceleration sender -

G251- in measured value block 006 ⇒ page 46 .

2. Interrogate fault memory ⇒ page 17 .

3. Erase fault memory ⇒ page 38 .

4. Conclude the transfer of data with the function “06 - End

output”.

5. Switch off ignition.

6. Switch ignition on again.

7. Perform zero compensation again.

3.8 Erasing fault memory

Note

If fault memory cannot be erased, interrogate fault memory again and rectify fault.

Requirements

• Fault memory interrogated ⇒ page 38 .

• All faults rectified.

After fault memory has been interrogated:

Indicated on -VAS 5051 A- :

– From list -1- select function “05 - Erase fault memory”.

38 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

1 - No display (prior to erasing) or

- Fault memory erased

Note

If the message “Fault memory not yet interrogated” appears in display zone -1-, this means that the test sequence has not been precisely observed. Fault memory cannot be erased until it has been interrogated.

2 - Note: Do you want to execute the function? Note: Data will be erased!

– Touch OK key in display -2-.

– Terminate function “05 - Erasing fault memory” by touching

← key.

3.9 End output

Audi TT 1999 ➤

Indicated on -VAS 5051 A- :

– From list -1- select function “06 - End output”.

Indicated on -VAS 5051 A- :

– When this display appears switch off ignition and unplug di‐

agnostic connector.

– Switch on ignition.

• The ABS warning lamp -K47- should go out after approx. 2 seconds.

3.10 Renewing and coding control unit

A new ABS with EDL control unit -J104- supplied as a replace‐ ment part is not encoded. The control unit must be encoded according to the type of drive train after fitting.

– Removing and installing control unit and hydraulic unit ⇒

Brake system; Rep. Gr. 45 .

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 39

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Note

If the ABS with EDL control unit -J104- is not coded (Code 00000), the ABS warning lamp -K47- -item 2- will flash once per second. The red “brake warning” symbol will start flashing when road speed first exceeds 10 km/h or engine speed first exceeds 2000 rpm after the ignition is switched on.

– Connect vehicle diagnostic, testing and information system -

VAS 5051 A- ⇒ page 7 and select vehicle system “03 - Brake electronics”. When doing this the ignition must be switched on.

Indicated on -VAS 5051 A- :

– From list -1- select diagnostic function “07 - Code control unit”.

Indicated on -VAS 5051 A- :

1 - Enter code word

Front-wheel drive vehicles Code number 13204

Four-wheel drive vehicles Code number 13504

Coding table

– Use keypad -2- to enter 5-digit code number according to cod‐

ing table and confirm entry by touching Q key.

Indicated on -VAS 5051 A- :

1 - Coding in progress

– Wait until next readout appears.

1 - Vehicle system coding completed

2 - Control unit identification with new code number (previous

code number in brackets)

40 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

Note

If the control unit is incorrectly coded, the ABS warning lamp -K47-

-item 2- will light up continuously. The “brake warning” symbol

-1- will light up when road speed first exceeds 10 km/h or engine

speed first exceeds 2000 rpm after the ignition is switched on.

– Terminate function “07 - Code control unit” by touching ← key.

Front-wheel drive vehicles:

The work sequence “Renewing and coding control unit” is com‐ pleted with this last step.

Four-wheel drive vehicles:

Indicated on -VAS 5051 A- :

– From list -1- select diagnostic function “11 - Login procedure”

or “11 - Coding II”.

Audi TT 1999 ➤

Indicated on -VAS 5051 A- :

1 - Enter code word

– Use keypad -2- to enter code “40168” and confirm entry by

touching Q key.

Note

If display on -VAS 5051 A- reads “function unknown or function can not be performed at present” the login procedure or coding II were not successful. Repeat login procedure or coding II.

– Terminate function “11 - Login procedure” or “11 - Coding II”

by touching ← key.

Indicated on -VAS 5051 A- :

– From list -1-, select function “04 - Basic setting”.

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 41

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

1 - Enter display group

– Use keypad -2- to enter “069” for “display group number 069”

and confirm by pressing the Q key.

• The ABS warning lamp -K47- flashes.

Indicated on -VAS 5051 A- :

A - Basic setting

B - Display group 69

1 - Zero compensation OK

4 - 0.3 m/s

2

Note

The display does not return to 0.00 m/s2 after performing zero compensation successfully.

– Terminate function “04 - Basic setting” by pressing the ← key.

The work sequence “Renewing and coding control unit” is com‐ pleted with this last step.

Note

If a fault is detected during zero compensation ⇒ page 38 .

3.11 Measured value block

The control unit can transfer a considerable amount of test data. This test data provides information about the operational condi‐ tion of the system and/or sensors connected. In many cases the transferred test data can be used to assist fault finding and fault rectification. Since all the information cannot be evaluated simul‐ taneously, the test data is categorised in display groups which can be selected individually via the display group numbers.

WARNING

♦ To avoid any risk of accident, observe the safety precau‐

tions when using test instruments while road testing the vehicle ⇒ “1.3 Safety precautions”, page 4 and

⇒ “1.6 Road test”, page 6 .

♦ The ABS/EDL function is deactivated when using vehicle

diagnostic, testing and information system -VAS 5051 Ain the mode “vehicle self-diagnosis” while road testing the vehicle. However, this is not indicated by illumination of the warning lamps.

42 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

Note

Self-diagnosis of ABS with EDL control unit -J104- is terminated if a road speed of 20 km/h is exceeded.

If a fault occurs while function “08 - Reading measured value block” is being performed, it will be detected. This is indicated by the ABS warning lamp -K47- lighting up, and helps to trace “sporadic faults”.

3.11.1 Reading measured value block

– Connect vehicle diagnostic, testing and information system -

VAS 5051 A- ⇒ page 7 and select vehicle system “03 - Brake electronics”. Ignition must be on or engine must be idling.

Indicated on -VAS 5051 A- :

– From list -1- select diagnostic function “08 - Read measured

value block”.

Audi TT 1999 ➤

Indicated on -VAS 5051 A- :

1 - Enter display group

– Use keypad -2- to select the relevant “Display group number”

⇒ page 44 and confirm by pressing the Q key.

Indicated on -VAS 5051 A- :

1 - Display zones 1 ... 4. If a display zone is vacant the respec‐

tive line remains blank

2 - Indicates the selected display group

3 - Another display group can be selected by pressing one of

the keys.

4 - Another function can be selected by pressing one of the

keys (e.g. selecting function “Basic setting” instead of “Read measured value block” and vice versa)

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 43

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

List of available display groups

Display group Display zone Signifies Refer to

001 1 Wheel speed, front left ⇒ page 44

2 Wheel speed, front right 3 Wheel speed, rear left 4 Wheel speed, rear right

002 1 Starting speed, front left ⇒ page 44

2 Starting speed, front right 3 Starting speed, rear left 4 Starting speed, rear right

003 1 Brake light switch -F- ⇒ page 45

2 … 4 Vacant

004 1 Communication with engine control unit ⇒ page 45

2 … 4 Vacant 005 006 1

Ignore Longitudinal acceleration sender -G251-

7)

⇒ page 46

2 … 4 Vacant

7) Four-wheel drive vehicles only.

3.11.2 Test table

Display group 001

This display group is used for checking allocation of speed sen‐ sors to wheels.

– Raise vehicle on lifting platform.

Display zones Explanation

1 ... km/h Wheel speed, front left (turn wheel by hand) 2 ... km/h Wheel speed, front right (turn wheel by hand) 3 ... km/h Wheel speed, rear left (turn wheel by hand) 4 ... km/h Wheel speed, rear right (turn wheel by hand)

Display group 002

This display group is used for the checking wheel speed sensors. The ABS with EDL control unit -J104- stores the first usable volt‐ age signals from the speed sensor when driving away and dis‐ plays these as set values.

Note

♦

A second mechanic is needed for reading the display when the vehicle is moving ⇒ “1.3 Safety precautions”, page 4 .

♦

The ABS/EDL function is deactivated when using vehicle di‐ agnosis, testing and information system -VAS 5051 A- in the function “Read measured value block” while road testing the vehicle. However, this is not indicated by illumination of the warning lamps.

♦

Self-diagnosis of ABS with EDL control unit -J104- is termina‐ ted if a road speed of 20 km/h is exceeded.

44 Rep. Gr.01 - Self-diagnosis, electrical checks

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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability

with respect to the correctness of information in this document. Copyright by AUDI AG.

Display zones Explanation

1 2

... km/h ... km/h

8)

– Drive away slowly until values are displayed on -VAS 5051 A- .

• The displayed values in display zones 1 and 2 must on no account be above 6 km/h when driving away slowly.

If the values are higher than these figures: – Check wheel speed sensors and rotors on front wheels for damage, proper

installation position and secure seating ⇒ Brake system; Rep. Gr. 45 .

3 4

... km/h ... km/h

8)

– Drive away slowly until values are displayed on -VAS 5051 A- .

• The displayed values in display zones 3 and 4 must not be above 2 km/h when driving away slowly.

If the values are higher than these figures: – Check wheel speed sensors and rotors on rear wheels for damage, proper

installation position and secure seating ⇒ Brake system; Rep. Gr. 45 .

8) When the vehicle is stationary the display will read 255 km/h.

Display group 003

Display zones Explanation

1 … Brake light switch -F- :

• 0 = Brake pedal not depressed, Brake light switch “OFF”

• 1 = Brake pedal depressed, Brake light switch “ON”

If readout is not as described:

– Perform electrical check, test step 4 ⇒ page 52 2 3 4

Vacant

Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

Display group 004

Display zones Explanation

1 … Communication with engine control unit:

• 0 = No communication with engine control unit via CAN bus

• 1 = Communication with engine control unit via CAN bus is OK

If display reads “0”:

– Check CAN bus wiring ⇒ page 9 2 3 4

Vacant

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 45

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Display group 006

Note

♦

A second mechanic is needed for reading the display when the vehicle is moving ⇒ “1.3 Safety precautions”, page 4 .

♦

The ABS/ESP function is deactivated when using vehicle di‐ agnosis, testing and information system -VAS 5051 A- in the function “read measured value block” while road testing the vehicle. However, this is not indicated by illumination of the warning lamps.

♦

Self-diagnosis of ABS with EDL control unit -J104- is termina‐ ted if a road speed of 20 km/h is exceeded.

Display zones Explanation

1

m/s

2

Specified values for longitudinal acceleration sensor -G251- .

•

Vehicle stationary: ± 0.5 m/s

• Forward acceleration: value increases continuously

• Reverse acceleration: negative (-) value increases continuously

If readout is not as described:

– Perform electrical check, test step 19 ⇒ page 58 2 3 4

Vacant

2

3.12 Login procedure or coding II

The login procedure or coding II is required for zero compensation of several components.

Procedure

– Connect vehicle diagnostic, testing and information system -

VAS 5051 A- ⇒ page 7 and select vehicle system “03 - Brake electronics”. When doing this the ignition must be switched on.

Indicated on -VAS 5051 A- :

– From list -1- select diagnostic function “11 - Login procedure”

or “11 - Coding II”.

46 Rep. Gr.01 - Self-diagnosis, electrical checks

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Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

1 - Enter code word

– Use keypad -2- to enter code “40168” and confirm entry by

touching Q key.

Note

If display on -VAS 5051 A- reads “function unknown or function can not be performed at present” the login procedure or coding II were not successful. Repeat login procedure or coding II.

– Terminate function “11 - Login procedure” or “11 - Coding II”

by touching ← key.

– Continue in function “04 - Basic setting” ⇒ page 37 .

3.13 Electrical check of ABS/EDL and ABS/EDL/TCS ITT Mark 20 without ESP

Special tools and workshop equipment required

♦ Hand-held multimeter -

V.A.G 1526 B- or vehicle diagnostic, testing and in‐ formation system VAS 5051 A- with test leads

-VAS 5051 A/7-

♦ Adapter set -V.A.G 1594 C-

♦ Test box -V.A.G 1598/21-

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 47

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

The test steps can be used:

♦ For vehicles on which the self diagnosis does not give any

indication of the source of the fault. Work through the complete electrical check.

♦ For vehicles on which the self diagnosis provides a direct in‐

dication of the source of the fault. Only carry out the test steps recommended in the fault table (to trace a specific fault).

Requirements

• Voltage supply of vehicle OK.

• Fuses OK ⇒ Current flow diagrams, Electrical fault finding and Fitting locations.

• Earth connections checked for corrosion and loose contact ⇒ Current flow diagrams, Electrical fault finding and Fitting lo‐ cations.

• All electrical consumers switched off.

3.14 Connecting adapter -V.A.G 1598/21-

(test box) to ABS with EDL control unit J104-

– Switch off ignition.

– Remove cover at front left in engine compartment -arrows-.

– If fitted, disconnect air intake hose for secondary air pump

-1- from air cleaner housing.

– Detach air intake hose -2- at air mass meter.

– Unplug electrical connector at air mass meter -3-.

– Unscrew bolts -4- and -5-.

– Take out air cleaner housing.

48 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

– Release 25-pin connector at ABS with EDL control unit -J104-

-arrow 1- and detach connector -arrow 2-.

– Connect adapter -V.A.G 1598/21- (test box) -item 1- to un‐

plugged 25-pin connector -2- of ABS with EDL control unit J104- .

Caution

To prevent damage to the electronic components, select the respective measuring range and note the test requirements prior to connecting test leads.

Audi TT 1999 ➤

– Perform all steps listed for “fault rectification if reading does

not match specification”.

– Only carry out the test steps recommended in the fault table

(to trace a specific fault).

– After performing electrical check, plug 25-pin connector onto

pins of ABS with EDL control unit -J104- and secure connec‐ tor.

Note

♦

Use hand-held multimeter -V.A.G 1526 B- with test leads from

-V.A.G 1594 C- or vehicle diagnostic, testing and information system -VAS 5051 A- with test leads -VAS 5051 A/7- for the electrical check.

♦

The socket designations of the adapter -V.A.G 1598/21- (test box) are identical to the contact designations of the ABS with EDL control unit -J104- in the current flow diagram.

♦

Incorrect test procedures can cause system damage. Do not make bridging connections between any contacts other than those listed in the test table.

♦

The specified values are valid for an ambient temperature be‐ tween 0 ... 40 °C.

♦

If measured values differ from specifications, locate fault ac‐ cording to current flow diagram.

♦

If the measured values only differ slightly from the specifica‐ tions, clean the sockets and plugs of the testers and test leads (with contact spray -G 000 700 04- ) and repeat the check.

♦

Before renewing components, check wiring and connections. Repeat resistance check on the component, particularly where specifications call for a resistance of less than 10Ω.

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 49

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

25-pin connector of ABS with EDL control unit -J104- / sockets on adapter -V.A.G 1598/21- (test box)

1 - Speed sensor, front left -G47- “+” 15 - ♦ Vehicles with TCS: Traction control system

switch -E132- and traction control system warning lamp -K86-

2 - Speed sensor, front left -G47- “–”

♦ Vehicles with four-wheel drive: Longitudinal

acceleration sender -G251-

3 - Coding bridge to contact 14 16 - ABS warning lamp -K474 - Power supply, terminal 15 in dash panel wiring

17 -

Longitudinal acceleration sender -G251-

harness (via fuse) 5 - Speed sensor, rear left -G46- “+” 18 - Brake light switch -F6 - Speed sensor, rear left -G46- “–” 19 - Speed sensor, front right -G45- “+” 7 - Diagnosis K-wire 20 - Speed sensor, front right -G45- “–” 8 - Earth point in wiring harness of engine com‐

partment 9 - Battery “+” via fuse 22 - Speed sensor, rear right -G44- “–”

21 - Vacant

10 - CAN bus Low 23 - Speed sensor, rear right -G44- “+” 11 - CAN bus High 24 - Earth terminal 31 12 - Vacant 25 - Battery “+” ( ABS hydraulic pump -V64- via

fuse)

13 -

Longitudinal acceleration sender -G251-

14 - Coding bridge to contact 3

9) Four-wheel drive vehicles only.

9)

3.15 Test table

9)

Overview of test steps

Item tested Test step

Power supply (terminal 30) for ABS hydraulic pump -

– Perform test step 1 ⇒ page 51

V64Power supply (terminal 30) for ABS hydraulic unit -

– Perform test step 2 ⇒ page 51

N55Power supply (terminal 15) for ABS with EDL control

– Perform test step 3 ⇒ page 51

unit -J104Brake light switch -F- – Perform test step 4 ⇒ page 52 Resistance of speed sensor, front right -G45- – Perform test step 5 ⇒ page 52 Resistance of speed sensor, front left -G47- – Perform test step 6 ⇒ page 52 Resistance of speed sensor, rear right -G44- – Perform test step 7 ⇒ page 53 Resistance of speed sensor, rear left -G46- – Perform test step 8 ⇒ page 53 Voltage signal of speed sensor, front right -G45- – Perform test step 9 ⇒ page 54 Voltage signal of speed sensor, front left -G47- – Perform test step 10 ⇒ page 54

50 Rep. Gr.01 - Self-diagnosis, electrical checks

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Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

Item tested Test step

Voltage signal of speed sensor, rear right -G44- – Perform test step 11 ⇒ page 54

Voltage signal of speed sensor, rear left -G46- – Perform test step 12 ⇒ page 55

Coding bridge – Perform test step 13 ⇒ page 55

ABS warning lamp -K47- – Perform test step 14 ⇒ page 55

“Brake warning” symbol in display of driver information

– Perform test step 15 ⇒ page 56

system.

ABS hydraulic pump -V64- – Perform test step 16 ⇒ page 56

Traction control system warning lamp -K86- – Perform test step 17 ⇒ page 57

Traction control system switch -E132- – Perform test step 18 ⇒ page 57

Wiring for longitudinal acceleration sender -G251- – Perform test step 19 ⇒ page 58

Test step No. 1

-V.A.G

Item tested Test conditions and addi‐

1598/21-

Sockets

24 + 25 Power supply

(terminal 30) for ABS hydraulic pump -V64-

Test step No. 2

-V.A.G

Item tested Test conditions and addi‐

1598/21-

Sockets

8 + 9 Power supply

(terminal 30) for ABS hydraulic unit -N55-

tional operations

• Ignition off

– Select measuring

range: voltage meas‐ urement

tional operations

• Ignition off

– Select measuring

range: voltage meas‐ urement

Specifica‐

tion

Approx.

battery volt‐

age

Specifica‐

tion

Approx.

battery volt‐

age

Fault rectification if reading does not match specification

– Check wiring according to cur‐

rent flow diagram:

♦ Between contact 24 and earth

♦ Between contact 25 and termi‐

nal 30

Fault rectification if reading does not match specification

– Check wiring according to cur‐

rent flow diagram:

♦ Between contact 8 and earth

♦ Between contact 9 and terminal

30

Test step No. 3

-V.A.G

Item tested Test conditions and addi‐

1598/21-

Sockets

8 + 4 Power supply

(terminal 15) for ABS with EDL control unit J104-

tional operations

• Ignition on

Specifica‐

tion

Fault rectification if reading does not match specification

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 51

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

-V.A.G

Item tested Test conditions and addi‐

1598/21-

Sockets

Test step No. 4

-V.A.G

Item tested Test conditions and addi‐

1598/21-

Sockets

8 + 18 Brake light switch

-F-

Specifica‐

tional operations

– Select measuring

range: voltage meas‐ urement

tion

Approx.

battery volt‐

age

Specifica‐

tional operations

• Ignition off

tion

– Select measuring

range: voltage meas‐ urement

– Brake pedal not oper‐

0 V – Check wiring according to cur‐

ated

– Brake pedal operated Approx.

battery volt‐

age

Fault rectification if reading does not match specification

– Check wiring according to cur‐

rent flow diagram:

♦ Between contact 8 and earth

♦ Between contact 4 and terminal

15

Fault rectification if reading does not match specification

rent flow diagram:

♦ Between contact 8 and earth

♦ Between contact 18 and termi‐

nal 30

Test step No. 5

-V.A.G

Item tested Test conditions and addi‐

1598/21-

Sockets

19 + 20 Resistance of

speed sensor, front right -G45-

Test step No. 6

-V.A.G

Item tested Test conditions and addi‐

1598/21-

Sockets

1 + 2 Resistance of

speed sensor, front left -G47-

tional operations

• Ignition off

– Select measuring

range: resistance

Specifica‐

tion

1.0...1.3 kΩ – Check connector of speed sen‐

Fault rectification if reading does not match specification

sor

measurement

– Move wiring to speed sensor

when checking (loose contact)

Specifica‐

tional operations

• Ignition off

tion

– Renew speed sensor if wiring is

OK.

Fault rectification if reading does not match specification

52 Rep. Gr.01 - Self-diagnosis, electrical checks

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Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

-V.A.G

Item tested Test conditions and addi‐

1598/21-

Sockets

Test step No. 7

-V.A.G

Item tested Test conditions and addi‐

1598/21-

Sockets

22 + 23 Resistance of

speed sensor, rear right -G44-

tional operations

– Select measuring

range: resistance measurement

tional operations

• Ignition off

– Select measuring

range: resistance measurement

Specifica‐

tion

Fault rectification if reading does not match specification

1.0...1.3 kΩ – Check connector of speed sen‐ sor

– Move wiring to speed sensor

when checking (loose contact)

– Renew speed sensor if wiring is

OK.

Specifica‐

tion

Fault rectification if reading does not match specification

1.0...1.3 kΩ – Check connector of speed sen‐ sor

– Move wiring to speed sensor

when checking (loose contact)

Test step No. 8

-V.A.G

Item tested Test conditions and addi‐

1598/21-

Sockets

5 + 6 Resistance of

speed sensor, rear left -G46-

– Renew speed sensor if wiring is

OK.

tional operations

• Ignition off

– Select measuring

range: resistance

Specifica‐

tion

1.0...1.3 kΩ – Check connector of speed sen‐

Fault rectification if reading does not match specification

sor

measurement

– Move wiring to speed sensor

when checking (loose contact)

– Renew speed sensor if wiring is

OK.

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 53

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Test step No. 9

-V.A.G

Item tested Test conditions and addi‐

1598/21-

Sockets

19 + 20 Voltage signal of

speed sensor, front right -G45-

Test step No. 10

-V.A.G

Item tested Test conditions and addi‐

1598/21-

Sockets

1 + 2 Voltage signal of

speed sensor, front left -G47-

tional operations

• Vehicle raised

• Ignition off

– Select measuring

range: voltage meas‐ urement (alternating voltage)

– Rotate front right

wheel at approx. 1 revolution per second.

tional operations

• Vehicle raised

• Ignition off

– Select measuring

range: voltage meas‐ urement (alternating voltage)

– Rotate front left wheel

at approx. 1 revolution per second

Specifica‐

tion

Min. 65 mV

alternating

voltage

Specifica‐

tion

Min. 65 mV

alternating

voltage

Fault rectification if reading does not match specification

– Check speed sensor for inter‐

changed wiring (read measured value block 001 ⇒ page 44 )

– Check installation of speed sen‐

sor and rotor ⇒ Brake system; Rep. Gr. 45

Fault rectification if reading does not match specification

– Check speed sensor for inter‐

changed wiring (read measured value block 001 ⇒ page 44 )

Test step No. 11

-V.A.G

Item tested Test conditions and addi‐

1598/21-

Sockets

22 + 23 Voltage signal of

speed sensor, rear right -G44-

– Check installation of speed sen‐

sor and rotor ⇒ Brake system; Rep. Gr. 45

tional operations

• Vehicle raised

Specifica‐

tion

Fault rectification if reading does not match specification

• Ignition off

– Select measuring

range: voltage meas‐ urement (alternating voltage)

– Rotate rear right

wheel at approx. 1 revolution per second

190...

1140 mV al‐

ternating

– Check speed sensor for inter‐

changed wiring (read measured value block 001 ⇒ page 44 )

voltage

– Check installation of speed sen‐

sor and rotor ⇒ Brake system; Rep. Gr. 45

54 Rep. Gr.01 - Self-diagnosis, electrical checks

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Test step No. 12

Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

-V.A.G

1598/21-

Item tested Test conditions and addi‐

tional operations

Sockets

5 + 6 Voltage signal of

speed sensor, rear left -G46-

• Vehicle raised

• Ignition off

– Select measuring

range: voltage meas‐ urement (alternating voltage)

– Rotate rear left wheel

at approx. 1 revolution per second

Test step No. 13

-V.A.G

1598/21-

Item tested Test conditions and addi‐

tional operations

Sockets

3 + 14 Coding bridge • Ignition off

– Select measuring

range: resistance measurement

Specifica‐

tion

Fault rectification if reading does not match specification

190...

1140 mV al‐

ternating

– Check speed sensor for inter‐

changed wiring (read measured value block 001 ⇒ page 44 )

voltage

– Check installation of speed sen‐

sor and rotor ⇒ Brake system; Rep. Gr. 45

Specifica‐

tion

Fault rectification if reading does not match specification

0…1 Ω – Check wiring and contacts in

plug

– Renew coding bridge if test re‐

sult does not match specifica‐ tion

Test step No. 14

-V.A.G

1598/21-

Item tested Test conditions and addi‐

tional operations

Sockets

– ABS warning

lamp -K47-

• Ignition off

• 25-pin connector con‐ nected to ABS with EDL control unit J104-

– Switch on ignition ABS warn‐

Specifica‐

tion

ing lamp K47- should light up for 2

seconds

and then go

out

Fault rectification if reading does not match specification

– Switch off ignition – Connect test box -

V.A.G 1598/21-

– Check wiring according to cur‐

rent flow diagram:

♦ Perform test step 3

♦ Check wiring between contact

16 of -V.A.G 1598/21- and in‐ strument cluster.

– Interrogate fault memory of in‐

strument cluster (dash panel in‐ sert) ⇒ Electrical system, selfdiagnosis; Rep. Gr. 01

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 55

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Test step No. 15

-V.A.G

Item tested Test conditions and addi‐

1598/21-

Sockets

– “Brake warning”

symbol in display of driver informa‐ tion system.

Test step No. 16

tional operations

• Ignition off

• 25-pin connector con‐ nected to ABS with EDL control unit J104-

• Electrical connector unplugged from one of the front speed sen‐ sors.

– Switch on ignition,

start engine and in‐ crease engine speed to above 2000 rpm.

– Plug in electrical con‐

nector after testing is completed and inter‐ rogate and erase fault memory

Specifica‐

tion

“Brake

warning”

symbol

lights up

Fault rectification if reading does not match specification

– Switch off ignition – Connect test box -

V.A.G 1598/21-

– Check wiring according to cur‐

rent flow diagram:

♦ Perform test step 3

♦ Check wiring between contact

16 of -V.A.G 1598/21- and in‐ strument cluster.

– Interrogate fault memory of in‐

strument cluster (dash panel in‐ sert) ⇒ Electrical system, selfdiagnosis; Rep. Gr. 01

-V.A.G

Item tested Test conditions and addi‐

1598/21-

Sockets

– ABS hydraulic

pump -V64-

tional operations

• 25-pin connector con‐ nected to ABS with EDL control unit J104-

• Ignition on

• Vehicle diagnostic, testing and informa‐ tion system -VAS 5051 A- connected

– Initiate final control di‐

agnosis ⇒ page 25 and activate ABS hy‐ draulic pump -V64-

Specifica‐

tion

Pump mo‐

tor starts up

Fault rectification if reading does not match specification

– Switch off ignition – Check wiring according to cur‐

rent flow diagram:

♦ Perform test step 1

♦ Wiring from contact 1 of 2-pin

connector at ABS hydraulic pump -V64- to control unit

♦ Wiring from contact 2 of 2-pin

connector at ABS hydraulic pump -V64- to control unit

– If no fault is found in wiring, re‐

move hydraulic control unit and renew hydraulic pump with valve block ⇒ Brake system; Rep. Gr. 45

56 Rep. Gr.01 - Self-diagnosis, electrical checks

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Test step No. 17

Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

-V.A.G

Item tested Test conditions and addi‐

1598/21-

Sockets

– Traction control

system warning lamp -K86-

Specifica‐

tional operations

• No faults stored in

tion

fault memory

• Ignition off

• 25-pin connector con‐ nected to ABS with EDL control unit J104-

– Switch on ignition Traction

control sys‐

tem warn‐

ing lamp K86- should light up for 2

seconds

and then go

out

Fault rectification if reading does not match specification

– Switch off ignition – Connect test box -

V.A.G 1598/21-

– Check wiring according to cur‐

rent flow diagram:

♦ Perform test step 3

♦ Check wiring between contact

15 of -V.A.G 1598/21- and in‐ strument cluster.

– Interrogate fault memory of in‐

strument cluster (dash panel in‐ sert) ⇒ Electrical system, selfdiagnosis; Rep. Gr. 01

Test step No. 18

-V.A.G

Item tested Test conditions and addi‐

1598/21-

Sockets

– Traction control

system switch E132-

tional operations

• Ignition off

Specifica‐

tion

Fault rectification if reading does not match specification

• 25-pin connector con‐ nected to ABS with EDL control unit J104-

• Test step 17 per‐ formed

– Switch on ignition

Traction

control sys‐

– Operate traction con‐

trol system switch E132-

tem warn‐ ing lamp -

K86- lights

up

– Operate traction con‐

trol system switch E132- again

Traction

control sys‐

tem warn‐ ing lamp -

– Switch off ignition

– Connect test box -

V.A.G 1598/21-

K86- goes

out

3. ABS/EDL and ABS/EDL/TCS, ITT Mark 20 without ESP 57

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

-V.A.G

Item tested Test conditions and addi‐

1598/21-

Sockets

8 + 15

Test step No. 19

-V.A.G

Item tested Test conditions and addi‐

1598/21-

Sockets

10)

13 + 1

Wiring for longitu‐ dinal acceleration sender -G251-

tional operations

– Select measuring

range: voltage meas‐ urement

– Switch on ignition – Do not operate Trac‐

tion control system switch -E132-

– Operate traction con‐

trol system switch E132-

tional operations

• Ignition off

• Electrical connector at longitudinal accelera‐ tion sender -G251unplugged

Specifica‐

tion

Fault rectification if reading does not match specification

Approx. 0 V – Check fuses and wiring accord‐

ing to current flow diagram:

♦ Between contact 15 of -V.A.G

1598/21- and contact 5 of switch

♦ Between contact 6 of switch and

terminal 15

♦ Between contact 2 of switch and

earth

Approx.

– Renew switch if wiring is OK.

battery volt‐

age

Specifica‐

tion

Fault rectification if reading does not match specification

– Select measuring

range: resistance

17 + 2

15 + 3

10)

measurement

– Check wiring for short

to positive or earth.

10) Contact at connector of longitudinal acceleration sender -G251- .

max. 1.5Ω – Service wiring according to cur‐

rent flow diagram max. 1.5Ω max. 1.5Ω

∞ Ω

58 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

4 ABS/EDL/TCS/ESP ITT Mark 20

♦ The Audi TT with ESP is equipped with the ABS/EDL/ESP ITT

Mark 20 system or the ABS/EDL/TCS/ESP ITT Mark 20 sys‐ tem.

♦ The data signals are transmitted via CAN bus.

4.1 Retrofit installation of ESP

♦ ESP may have been retrofitted by AUDI AG on vehicles not

originally equipped with this system. These vehicles are iden‐ tified by the PR number “1AZ” on the data sticker.

♦ Another identifying feature is the adapter connector -1- on the

air cleaner housing.

♦ This connector must not be unplugged by the workshop. Self-

diagnosis and electrical check are as for the ESP fitted as standard.

4.2 Electrical/electronic components and fitting locations

Audi TT 1999 ➤

1 - Rotor for speed sensor (rear right)

❑ Checking speed sensor

rotor ⇒ Brake system; Rep. Gr. 45

❑ Speed sensor rotor is

welded to wheel hub; re‐ moving and installing wheel hub ⇒ Running gear, front-wheel drive and four-wheel drive; Rep. Gr. 42

2 - Rear right speed sensor G44-

❑ Removing and instal‐

ling, fitting speed sensor wiring ⇒ Brake system; Rep. Gr. 45

3 - Rear left speed sensor G46-

❑ Removing and instal‐

ling, fitting speed sensor wiring ⇒ Brake system; Rep. Gr. 45

4 - Rotor for speed sensor (rear left)

❑ Checking speed sensor

rotor ⇒ Brake system; Rep. Gr. 45

❑ Speed sensor rotor is

welded to wheel hub; re‐ moving and installing wheel hub ⇒ Running gear, front-wheel drive and four-wheel drive; Rep. Gr. 42

4. ABS/EDL/TCS/ESP ITT Mark 20 59

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

5 - Handbrake warning lamp -K14-

❑ Fitting location: in instrument cluster ❑ Function ⇒ page 14

6 - ABS warning lamp -K47-

❑ Fitting location: in instrument cluster ❑ Function ⇒ page 14

7 - “Brake warning” symbol

❑ Appears in the display of the driver information system ❑ Function ⇒ page 14

8 - Stabilisation program warning lamp -K155-

❑ Fitting location: in instrument cluster ❑ Function ⇒ page 14

9 - Brake light suppression relay (ESP) -J508-

❑ Fitting location: in 13-position relay carrier behind driver's storage compartment

10 - Brake light switch -F-

❑ Can be checked via reading measured value block ⇒ page 113 ❑ Removing and installing ⇒ Brake system; Rep. Gr. 45

11 - Rotor for speed sensor, front left

❑ Checking speed sensor rotor ⇒ Brake system; Rep. Gr. 45 ❑ Speed sensor rotor is welded to wheel hub; removing and installing wheel hub ⇒ Running gear, front-

wheel drive and four-wheel drive; Rep. Gr. 40

12 - Front left speed sensor -G47-

❑ Removing and installing, fitting speed sensor wiring ⇒ Brake system; Rep. Gr. 45

13 - Hydraulic control unit

❑ The hydraulic control unit comprises the ABS hydraulic pump -V64- , the ABS hydraulic unit -N55- and

the ABS with EDL control unit -J104- . ❑ Fitting location on left-hand drive vehicles ⇒ page 61 ❑ Fitting location on right-hand drive vehicles ⇒ page 62 ❑ Tested by self-diagnosis ❑ Only unplug 47-pin connector when the ignition is switched off ❑ Assignment of 47-pin connector ⇒ page 120 ❑ Removing and installing ⇒ Brake system; Rep. Gr. 45 ❑ Perform coding of ABS with EDL control unit -J104- after renewal ⇒ page 103

14 - Rotor for speed sensor, front right

❑ Checking speed sensor rotor ⇒ Brake system; Rep. Gr. 45 ❑ Speed sensor rotor is welded to wheel hub; removing and installing wheel hub ⇒ Running gear, front-

wheel drive and four-wheel drive; Rep. Gr. 40

15 - Front right speed sensor -G45-

❑ Removing and installing, fitting speed sensor wiring ⇒ Brake system; Rep. Gr. 45

16 - Longitudinal acceleration sender -G251-

❑ Only four-wheel drive vehicles ❑ Fitting location: at A-pillar on passenger's side ❑ Can be checked via reading measured value block ⇒ page 115 ❑ Refer to ⇒ Brake system; Rep. Gr. 45 for removing and installing, then perform zero compensation in

basic setting ⇒ page 97

17 - Brake pressure sender 2 -G214-

❑ Can be checked via reading measured value block ⇒ page 114 ❑ Refer to ⇒ Brake system; Rep. Gr. 45 for removing and installing, then perform zero compensation in

basic setting ⇒ page 95

60 Rep. Gr.01 - Self-diagnosis, electrical checks

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Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

18 - Brake pressure sender 1 -G201-

❑ Can be checked via reading measured value block ⇒ page 114 ❑ Refer to ⇒ Brake system; Rep. Gr. 45 for removing and installing, then perform zero compensation in

basic setting ⇒ page 95

19 - Brake pressure solenoid trip switch -F84-

❑ Can be checked in basic setting ⇒ page 87 and in measured value block ⇒ page 113 ❑ Brake servo must be renewed completely if brake pressure solenoid trip switch is defective

20 - Brake pressure solenoid -N247-

❑ Can be checked in basic setting ⇒ page 87 ❑ Brake servo must be renewed completely if brake pressure solenoid is defective

21 - Brake fluid level warning contact -F34-

22 - Lateral acceleration sender -G200-

❑ Fitting location: next to steering column ❑ Can be checked via reading measured value block ⇒ page 114 ❑ Refer to ⇒ Brake system; Rep. Gr. 45 for removing and installing, then perform zero compensation in

basic setting ⇒ page 93

23 - Yaw rate sender -G202-

❑ Fitting location: next to steering column ❑ Can be checked via reading measured value block ⇒ page 114 ❑ Removing and installing ⇒ Brake system; Rep. Gr. 45

24 - Button for TCS and ESP -E256-

❑ Fitting location: on the centre console

25 - Steering angle sender -G85-

❑ Fitting location: on steering column between steering wheel and steering column switch ❑ Can be checked via reading measured value block ⇒ page 114 ❑ Refer to ⇒ Brake system; Rep. Gr. 45 for removing and installing, then perform zero compensation in

basic setting ⇒ page 91

26 - Handbrake warning switch -F9-

❑ Fitting location: on handbrake lever

Hydraulic control unit on vehicles with left-hand drive

1 - Brake servo (10”)

2 - Hydraulic unit

3 - ABS with EDL control unit -J104- , 47-pin (bolted to hydraulic

unit)

4. ABS/EDL/TCS/ESP ITT Mark 20 61

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Hydraulic control unit on vehicles with right-hand drive

1 - Brake servo (7”/8”)

2 - Hydraulic unit

3 - ABS with EDL control unit -J104- , 47-pin (bolted to hydraulic

unit)

4.3 Faults displayed by warning lamps in in‐ strument cluster

1 - “Brake warning” symbol

2 - ABS warning lamp -K47-

3 - Handbrake warning lamp -K14-

4 - Stabilisation program warning lamp -K155-

“Brake warning”

symbol

ABS warning

lamp -K47-

Stabilisation

program warn‐

ing lamp -K155-

11)

Explanation

On On On Test sequence after switching on ignition (first two sec‐

onds). Off Off Off System OK (2 seconds after switching on ignition) Off Off On TCS/ESP failure or TCS/ESP deactivated by switch;

ABS, EDL and EBPD are active Off Off flashes TCS/ESP control function is operating Off On On ABS/EDL/TCS system failure (e.g. wheel speed sen‐

sor defective), the EBPD remains fully functional. On On On ABS/EDL/TCS/EBPD system failure (e.g. several

wheel speed sensors defective) On Off Off Brake fluid level too low; all systems remain functional

11) Used to be designated as traction control system warning lamp -K86- in cur‐ rent flow diagrams of an earlier date.

WARNING

There is a risk of accident if the ABS warning lamp -K47- and the “brake warning symbol” both light up.The function of the brake system will be impaired. As the brake pressure is no longer controlled by the electronic brake force distribution the rear wheels tend to brake excessively.Due to this the rear of the vehicle may break away unexpectedly.

62 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

The ABS warning lamp -K47- -item 2- lights up during the test sequence (self-test)

The system runs through an automatic test sequence when the ignition is switched on: the ABS warning lamp -K47- is activated by the ABS with EDL control unit -J104- and lights up for 2 sec‐ onds. During this period the control unit tests the following func‐ tions via self-test.

♦ The voltage supply is checked, at least 10.0 V.

♦ The control unit including the valve windings is checked.

♦ A speed sensor check (electrical test) is carried out; this is only

completed at 20 km/h.

♦ Control unit code is checked.

If the system does not perform the test sequence:

– Check voltage supply of ABS with EDL control unit -J104-

(perform electrical check, step 3 ⇒ page 123 ).

The ABS warning lamp -K47- -item 2- stays on after the test se‐ quence is completed

If a fault affecting only the anti-lock brake system is detected by self-diagnosis, the ABS is switched off. The conventional brake system remains fully functional.

The causes of the fault may be as follows:

♦ Voltage supply is below 10 Volts.

♦ A fault exists which affects only the ABS.

♦ A sensor fault has occurred after the last start (sporadic fault).

In this case the ABS warning lamp goes out automatically after the vehicle is started again and the road speed exceeds 20 km/ h.

♦ Connection between ABS with EDL control unit -J104- and in‐

strument cluster is faulty or instrument cluster faulty (perform electrical check, step 14 ⇒ page 127 ).

Audi TT 1999 ➤

The ABS warning lamp -K47- -item 2- goes out after the test se‐ quence is completed, but “brake warning symbol” -1- remains on and the gong sounds three times

All systems remain functional.

The causes of the fault may be as follows:

♦ Brake fluid level too low.

♦ Fault in instrument cluster ⇒ Electrical system, self-diagnosis;

Rep. Gr. 01 or ⇒ Current flow diagrams, Electrical fault finding and Fitting locations.

4. ABS/EDL/TCS/ESP ITT Mark 20 63

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

A - Vehicles without navigation system: the ABS warning lamp K47- -item 2- does not go out after the test sequence is comple‐ ted, and “brake warning” symbol -1- is on

B - Vehicles with navigation system: the ABS warning lamp -K47-

-item 2- does not go out after test sequence is completed and handbrake warning lamp -K14- -3- lights up when vehicle speed first exceeds 10 km/h or engine speed first exceeds 2000 rpm, and the gong sounds three times

The ABS system is defective and the EBPD system deactivated.

WARNING

There is a risk of accident if the ABS warning lamp -K47- and the “brake warning symbol” both light up.The function of the brake system will be impaired. As the brake pressure is no longer controlled by the electronic brake force distribution the rear wheels tend to brake excessively.Due to this the rear of the vehicle may break away unexpectedly.

The stabilising program warning lamp -K155- -item 4- remains on after the test sequence is completed

The causes of the fault may be as follows:

♦ A fault in the system affecting only the TCS/ESP. ABS/EDL

and EBPD remain fully functional.

♦ The TCS/ESP system was switched off by the TCS and ESP

button -E256- .

♦ Short circuit to positive in TCS and ESP button -E256-

♦ Short circuit to earth for activation of stabilisation program

warning lamp -K155- .

♦ Open circuit in wiring for activation of stabilisation program

warning lamp -K155- .

The stabilisation program warning lamp -K155- -item 4- lights up for 100 milliseconds after switching ignition on

♦ A coding without TCS/ESP control has been entered.

64 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

The ABS warning lamp -K47- -item 2- and the “brake warning” symbol -1- flash and the stabilisation program warning lamp K155- remains on after the test sequence is completed

The causes of the fault may be as follows:

♦ The control unit is not coded (Code 00000).

Note

If the ABS warning lamp -K47- and the “brake warning” symbol do not light up but the brake system is not fully functional, the fault must be traced in the conventional brake system ⇒ Brake system; Rep. Gr. 46 and ⇒ Brake system; Rep. Gr. 47 .

4.4 Performing self-diagnosis of ABS/EDL/ TCS/ESP ITT Mark 20 system

List of available functions

– With ignition switched off, connect vehicle diagnostic, testing

and information system -VAS 5051 A- with diagnosis lead VAS 5051 A/1- to diagnosis connector and select vehicle system “03 - Brake electronics” ⇒ page 7 .

The following functions are available from the list -1-:

Audi TT 1999 ➤

Functions Page

02 Interrogate fault memory ⇒ page 65 03 Final control diagnosis ⇒ page 77 04 Basic setting ⇒ page 84 05 Erase fault memory ⇒ page 102 06 End output ⇒ page 103 07 Code control unit ⇒ page 103 08 Read measured value block ⇒ page 110 11 Login procedure or coding II ⇒ page 116

The other functions displayed are currently not available, or can be disregarded.

4.5 Interrogating fault memory

– Connect vehicle diagnostic, testing and information system -

VAS 5051 A- ⇒ page 7 and select vehicle system “03 - Brake electronics”. When doing this the ignition must be switched on.

Indicated on -VAS 5051 A- :

– From list -1- select function “02 - Interrogate fault memory”.

4. ABS/EDL/TCS/ESP ITT Mark 20 65

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

-1- Content of fault memory No faults detected or X faults detected

-2- Fault Fault code Fault location Type of fault

A - If a fault was detected:

– Print out information on screen or self-diagnosis log.

– Terminate function “02 - Interrogate fault memory” by touching

← key.

Indicated on -VAS 5051 A- :

– Rectify fault(s) according to fault tables ⇒ page 66 .

– From list -1- select function “02 - Interrogate fault memory” and

erase fault memory ⇒ page 102 .

– From list -1- select function “06 - End output” ⇒ page 103 .

– Perform road test and interrogate fault memory again.

B - If no fault was detected:

– Terminate function “02 - Interrogate fault memory” by touching

← key.

– Select function “06 - End output” from list ⇒ page 103 .

4.6 Fault tables

Note

♦

The following table includes all faults which can be detected by the ABS with EDL control unit -J104- and displayed by VAS 5051 A- when interrogating the fault memory.

♦

The contents of the fault memory remains stored until the memory is erased; Erasing fault memory ⇒ page 102 .

♦

Faults are listed according to a 5-digit fault code, which ap‐ pears in the left-hand column of the fault table.

♦

Sporadic (intermittent) faults are identified as such by the word “sporadic” appearing on the display.

♦

Check wiring and connectors going to the relevant compo‐ nents according to current flow diagram before renewing com‐ ponents indicated as faulty by -VAS 5051 A- .Also check earth connections according to current flow diagram. This is partic‐ ularly important if faults are indicated as being “sporadic”.

Fault 00283

Display on -

VAS 5051 A-

00283 Front left speed sensor -G47-

♦ Open circuit, loose contact or short to

positive or earth in speed sensor wire or speed sensor

Possible cause of fault Fault remedy

– Perform electrical check, step 6

⇒ page 123 and step 10 ⇒ page 125

♦ Speed sensor winding defective

66 Rep. Gr.01 - Self-diagnosis, electrical checks

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Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

Display on -

VAS 5051 A-

♦ Speed sensor or rotor damaged – Check speed sensor and rotor ⇒ Brake

♦ ABS with EDL control unit -J104- defec‐

tive

00283 Front left speed sensor -G47Mechanical fault

• This fault is only detec‐

♦ Excessive air gap between speed sensor

and rotor. ted above 20 km/h (carry out test drive).

♦ Outlet valves in hydraulic unit defective – Check hydraulic unit in final control diag‐

00283 Front left speed sensor -G47Signal outside tolerance

• This fault is only detec‐ ted above 20 km/h (carry out test

♦ Open circuit, loose contact or short to

positive or earth in speed sensor wire or speed sensor

♦ Speed sensor winding defective

drive).

Possible cause of fault Fault remedy

system; Rep. Gr. 45

– Remove hydraulic control unit, renew

control unit ⇒ Brake system; Rep. Gr. 45 , then code control unit ⇒ page 103

– Check installation of speed sensor and

rotor ⇒ Brake system; Rep. Gr. 45

nosis ⇒ page 77

– Perform electrical check, step 6

⇒ page 123 and step 10 ⇒ page 125

♦ Electrical interference from external in‐

terference sources (high frequency radi‐ ation, e.g. non-insulated ignition cable)

♦ Excessive air gap between speed sensor

and rotor.

♦ Speed sensor or rotor damaged – Check speed sensor and rotor ⇒ Brake

Fault 00285

Display on -

VAS 5051 A-

00285

Possible cause of fault Fault remedy

Front right speed sensor -G45-

♦ Open circuit, loose contact or short to

positive or earth in speed sensor wire or speed sensor

♦ Speed sensor winding defective

♦ Speed sensor or rotor damaged – Check speed sensor and rotor ⇒ Brake

♦ ABS with EDL control unit -J104- defec‐

tive

00285 Front right speed sensor -G45Mechanical fault

– Read measured value block 001

⇒ page 112

– Check installation of speed sensor and

rotor ⇒ Brake system; Rep. Gr. 45

system; Rep. Gr. 45

– Perform electrical check, step 5

⇒ page 123 and step 9 ⇒ page 125

system; Rep. Gr. 45

– Remove hydraulic control unit, renew

control unit ⇒ Brake system; Rep. Gr. 45 , then code control unit ⇒ page 103

4. ABS/EDL/TCS/ESP ITT Mark 20 67

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by AUDI AG.

Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

• This fault is only detec‐

♦ Excessive air gap between speed sensor

and rotor. ted above 20 km/h (carry out test drive).

♦ Outlet valves in hydraulic unit defective – Check hydraulic unit in final control diag‐

00285 Front right speed sensor -G45Signal outside tolerance

• This fault is only detec‐ ted above 20 km/h (carry out test

♦ Open circuit, loose contact or short to

positive or earth in speed sensor wire or speed sensor

♦ Speed sensor winding defective

drive).

♦ Electrical interference from external in‐

terference sources (high frequency radi‐ ation, e.g. non-insulated ignition cable)

♦ Excessive air gap between speed sensor

and rotor.

– Check installation of speed sensor and

rotor ⇒ Brake system; Rep. Gr. 45

nosis ⇒ page 77

– Perform electrical check, step 5

⇒ page 123 and step 9 ⇒ page 125

– Read measured value block 001

⇒ page 112

– Check installation of speed sensor and

rotor ⇒ Brake system; Rep. Gr. 45

♦ Speed sensor or rotor damaged – Check speed sensor and rotor ⇒ Brake

Fault 00287

Display on -

VAS 5051 A-

00287 Rear right speed sensor -G44-

♦ Open circuit, loose contact or short to

positive or earth in speed sensor wire or speed sensor

♦ Speed sensor winding defective

♦ Speed sensor or rotor damaged – Check speed sensor and rotor ⇒ Brake

♦ ABS with EDL control unit -J104- defec‐

tive

00287 Rear right speed sensor -G44Mechanical fault

• This fault is only detec‐ ted above 20

♦ Excessive air gap between speed sensor

and rotor.

km/h (carry out test drive).

system; Rep. Gr. 45

Possible cause of fault Fault remedy

– Perform electrical check, step 7

⇒ page 124 and step 11 ⇒ page 125

system; Rep. Gr. 45

– Remove hydraulic control unit, renew

control unit ⇒ Brake system; Rep. Gr. 45 , then code control unit ⇒ page 103

– Check installation of speed sensor and

rotor ⇒ Brake system; Rep. Gr. 45

♦ Outlet valves in hydraulic unit defective – Check hydraulic unit in final control diag‐

00287 Rear right speed sensor -G44Signal outside tolerance

68 Rep. Gr.01 - Self-diagnosis, electrical checks

nosis ⇒ page 77

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Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

Display on -

VAS 5051 A-

• This fault is only detec‐ ted above 20 km/h (carry out test

♦ Open circuit, loose contact or short to

positive or earth in speed sensor wire or speed sensor

♦ Speed sensor winding defective

drive).

♦ Electrical interference from external in‐

terference sources (high frequency radi‐ ation, e.g. non-insulated ignition cable)

♦ Excessive air gap between speed sensor

and rotor.

♦ Speed sensor or rotor damaged – Check speed sensor and rotor ⇒ Brake

Fault 00290

Display on -

VAS 5051 A-

00290 Rear left speed sensor -G46-

♦ Open circuit, loose contact or short to

positive or earth in speed sensor wire or speed sensor

♦ Speed sensor winding defective

Possible cause of fault Fault remedy

– Perform electrical check, step 7

⇒ page 124 and step 11 ⇒ page 125

– Read measured value block 001

⇒ page 112

– Check installation of speed sensor and

rotor ⇒ Brake system; Rep. Gr. 45

system; Rep. Gr. 45

Possible cause of fault Fault remedy

– Perform electrical check, step 8

⇒ page 124 and step 12 ⇒ page 126

♦ Speed sensor or rotor damaged – Check speed sensor and rotor ⇒ Brake

♦ ABS with EDL control unit -J104- defec‐

tive

00290 Rear left speed sensor -G46Mechanical fault

• This fault is only detec‐

♦ Excessive air gap between speed sensor

and rotor. ted above 20 km/h (carry out test drive).

♦ Outlet valves in hydraulic unit defective – Check hydraulic unit in final control diag‐

♦ Excessive air gap between speed sensor

and rotor.

00290 Rear left speed sensor -G46Signal outside tolerance

• This fault is only detec‐ ted above 20 km/h (carry out test

♦ Open circuit, loose contact or short to

positive or earth in speed sensor wire or speed sensor

♦ Speed sensor winding defective

drive).

system; Rep. Gr. 45

– Remove hydraulic control unit, renew

control unit ⇒ Brake system; Rep. Gr. 45 , then code control unit ⇒ page 103

– Check installation of speed sensor and

rotor ⇒ Brake system; Rep. Gr. 45

nosis ⇒ page 77

– Check installation of speed sensor and

rotor ⇒ Brake system; Rep. Gr. 45

– Perform electrical check, step 8

⇒ page 124 and step 12 ⇒ page 126

4. ABS/EDL/TCS/ESP ITT Mark 20 69

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Display on -

VAS 5051 A-

Fault 00538

Display on -

VAS 5051 A-

00538 Reference voltage

Possible cause of fault Fault remedy

♦ Electrical interference from external in‐

terference sources (high frequency radi‐

– Read measured value block 001

⇒ page 112

ation, e.g. non-insulated ignition cable)

♦ Excessive air gap between speed sensor

and rotor.

– Check installation of speed sensor and

rotor ⇒ Brake system; Rep. Gr. 45

♦ Speed sensor or rotor damaged – Check speed sensor and rotor ⇒ Brake

system; Rep. Gr. 45

Possible cause of fault Fault remedy

♦ Open circuit, loose contact or short circuit

to positive or earth in voltage supply wir‐ ing for lateral acceleration sender G200- , brake pressure sender 1 -G201- ,

– Perform electrical check, test step 19

⇒ page 130 , test step 20 ⇒ page 130 ,

test step 21 ⇒ page 131 , test step 22

⇒ page 131

yaw rate sender -G202- or brake pres‐ sure sender 2 -G214-

Fault 00668

Display on -

VAS 5051 A-

00668 Vehicle voltage, terminal 30 Signal outside tolerance

♦ Fuse defective

♦ Open circuit, loose circuit or short circuit

to positive or earth in voltage supply wir‐ ing

Fault 00778

Display on -

VAS 5051 A-

00778 Steering angle sender -G85No communication

♦ Faults in CAN bus wiring – Check CAN bus wiring between ABS with

♦ High and Low CAN bus wiring inter‐

changed

♦ The output of one of the control units

communicating via the CAN bus is de‐ fective.

Possible cause of fault Fault remedy

– Perform electrical check, step 1

⇒ page 122 and step 2 ⇒ page 122

Possible cause of fault Fault remedy

EDL control unit -J104- and steering an‐

gle sender -G85- ⇒ page 9

– Check CAN Bus wiring for interchanged

connections according to current flow di‐

agram

– Check CAN bus wiring ⇒ page 9

70 Rep. Gr.01 - Self-diagnosis, electrical checks

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by AUDI AG.

Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

Display on -

VAS 5051 A-

♦ Steering angle sender -G85- defective – Read measured value block 004

00778 Steering angle sender -G85No setting or wrong setting

♦ Steering angle sender -G85- sends no

values or incorrect values

00778 Steering angle sender -G85Mechanical fault

♦ Installation position of steering angle

sender -G85- not OK

♦ Running gear geometry not OK – Perform wheel alignment ⇒ Running

♦ No zero compensation performed after

removing and installing steering wheel

Possible cause of fault Fault remedy

⇒ page 114

– Renew sender ⇒ Brake system; Rep. Gr.

45 , then perform zero compensation in basic setting ⇒ page 91

– Perform zero compensation

⇒ page 91

– Check installation position of sender ⇒

Brake system; Rep. Gr. 45

gear, front-wheel drive and four-wheel drive; Rep. Gr. 44

– Perform zero compensation

⇒ page 91

00778 Steering angle sender -G85Implausible signal

♦ Installation position of steering angle

sender -G85- not OK

♦ Running gear geometry not OK – Perform wheel alignment ⇒ Running

♦ Vibrations in steering due to wear – Renew defective components, then per‐

00778 Steering angle sender -G85defective

♦ Steering angle sender -G85- sends no

values or incorrect values

Fault 00810

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

00810 Sender 1/2 for brake pressure Implausible signal

♦ Open circuit in earth connection to brake

pressure sender 1 -G201- or brake pres‐ sure sender 2 -G214-

♦ Short circuit in signal wiring to brake pres‐

sure sender 1 -G201- or brake pressure sender 2 -G214-

– Check installation position of sender ⇒

Brake system; Rep. Gr. 45

gear, front-wheel drive and four-wheel drive; Rep. Gr. 44

form zero compensation in basic setting

⇒ page 91

– Renew sender ⇒ Brake system; Rep. Gr.

45 , then perform zero compensation in basic setting ⇒ page 91

– Perform electrical check, step 21

⇒ page 131 and step 22 ⇒ page 131

4. ABS/EDL/TCS/ESP ITT Mark 20 71

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

♦ Brake pressure sender 1 -G201- or brake

pressure sender 2 -G214- defective

♦ One hydraulic brake circuit has failed – Check brake system ⇒ Brake system;

Fault 00812

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

00812 Brake pressure solenoid trip switch -F84-

♦ Open circuit, loose circuit or short circuit

to positive or earth in wiring connection going to brake pressure solenoid trip switch -F84-

♦ Brake pressure solenoid trip switch -F84-

defective

♦ Brake servo defective – Renew brake servo ⇒ Brake system;

– Renew sender ⇒ Brake system; Rep. Gr.

45 , then perform zero compensation in

basic setting ⇒ page 99

Rep. Gr. 47

– Perform electrical check, test step 23

⇒ page 131

– Perform function test in basic setting

⇒ page 87

Rep. Gr. 47 , then perform function test

in basic setting ⇒ page 87

Fault 00813

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

00813 Brake pressure sender 2 -G214Electrical fault in circuit

♦ Open circuit, loose circuit or short circuit

to positive or earth in wiring connection going to brake pressure sender 2 -G214-

♦ Brake pressure sender 2 -G214- defec‐

tive

Fault 00814

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

00814 Brake pressure solenoid -N247-

♦ Open circuit, loose circuit or short circuit

to positive or earth in wiring connection going to brake pressure solenoid -N247-

– Perform electrical check, test step 22

⇒ page 131

– Renew sender ⇒ Brake system; Rep. Gr.

45 , then perform zero compensation in

basic setting ⇒ page 95

– Perform electrical check, test step 24

⇒ page 132

♦ Brake pressure solenoid -N247- defec‐

tive

♦ Brake servo defective – Renew brake servo ⇒ Brake system;

72 Rep. Gr.01 - Self-diagnosis, electrical checks

– Perform function test in basic setting

⇒ page 87

Rep. Gr. 47 , then perform function test

in basic setting ⇒ page 87

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by AUDI AG.

Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

Display on -

VAS 5051 A-

♦ Output stage in ABS with EDL control unit

-J104- defective

Fault 01044

Display on -

VAS 5051 A-

01044 Control unit incorrectly coded

♦ An incorrect code number has been en‐

tered

♦ Only vehicles with front-wheel drive: con‐

tact 2 not connected

♦ Only vehicles with four-wheel drive: con‐

tact 2 connected to earth

♦ Coding bridges in wiring harness dam‐

aged

Possible cause of fault Fault remedy

– Remove hydraulic control unit, renew

control unit ⇒ Brake system; Rep. Gr. 45 , then code control unit ⇒ page 103

Possible cause of fault Fault remedy

– Check code ⇒ page 103

– Connect contact 2 to earth

– Remove earth connection at contact 2

– Check wires in wiring harness; perform

electrical check, test step 13

⇒ page 126

Fault 01130

Display on -

VAS 5051 A-

01130 ABS operation Signal outside tolerance

• This fault is only detec‐ ted above 20 km/h (carry out test drive).

♦ Electrical interference from external in‐

terference sources (high frequency radi‐ ation, e.g. non-insulated ignition cable)

♦ Open circuit, loose contact or short to

positive or earth in wiring

Fault 01276

Display on -

VAS 5051 A-

01276 ABS hydraulic pump -V64Signal outside tolerance

Possible cause of fault Fault remedy

– Check all electrical wiring and connectors

– Erase fault memory

– Perform test drive at more than 20 km/h

– Interrogate fault memory again

If the fault is not rectified: – Remove hydraulic control unit, renew

control unit ⇒ Brake system; Rep. Gr. 45 , then code control unit ⇒ page 103

Possible cause of fault Fault remedy

4. ABS/EDL/TCS/ESP ITT Mark 20 73

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

• This fault is only detec‐ ted above 20 km/h (carry

♦ Open circuit or short circuit to earth or

positive in internal wiring: ABS with EDL control unit -J104- / ABS hydraulic pump

-V64out test drive).

♦ ABS with EDL control unit -J104- defec‐

tive

♦ Pump motor defective – Renew hydraulic control unit ⇒ Brake

Fault 01279

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

01279 Longitudinal acceleration sender -G251Electrical fault in circuit

12)

♦ Open circuit, loose circuit or short circuit

to positive or earth in wiring connection going to longitudinal acceleration sender

-G251-

– Check ABS hydraulic pump -V64- via fi‐

nal control diagnosis ⇒ page 77

If ABS hydraulic pump -V64- starts running during final control diagnosis: – Perform electrical check, test step 1

⇒ page 122

– Check all wiring and connections for

short to positive or earth according to cur‐ rent flow diagram.

– Remove hydraulic control unit, renew

control unit ⇒ Brake system; Rep. Gr. 45 , then code control unit ⇒ page 103

system; Rep. Gr. 45

– Perform electrical check, test step 25

⇒ page 132

♦ Installation position of longitudinal accel‐

eration sender -G251- not OK

♦ Longitudinal acceleration sender -G251-

defective

12) Four-wheel drive vehicles only.

Fault 01312

Display on -

VAS 5051 A-

01312 Drive train data bus defective

13)

♦ ABS with EDL control unit -J104- incor‐

rectly coded

♦ Engine control unit incorrectly coded – Check coding of engine control unit ⇒

♦ Faults in CAN bus wiring – Check CAN bus wiring between engine

– Check installation position ⇒ Brake sys‐

tem; Rep. Gr. 45

– Read measured value block 006

⇒ page 115

– Renew sender ⇒ Brake system; Rep. Gr.

45 , then perform zero compensation in basic setting ⇒ page 97

Possible cause of fault Fault remedy

– Check code ⇒ page 103

Motronic injection and ignition system; Rep. Gr. 01

control unit and ABS with EDL control unit

-J104- ⇒ page 9

13) Is displayed together with fault “00778 - Steering angle sender: -G85 No communication”.

74 Rep. Gr.01 - Self-diagnosis, electrical checks

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Fault 01314

Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

01314 Engine control unit No communication

• Signals are transmitted between

When displayed as static fault: ♦ ABS with EDL control unit -J104- or en‐

gine control unit not CAN compatible ABS with EDL control unit -J104and engine

♦ Fault in engine control unit – Interrogate fault memory of engine con‐

control unit via CAN data bus

When displayed as static and sporadic fault: ♦ Faults in CAN bus wiring

♦ High and Low CAN bus wiring inter‐

changed

♦ The output of one of the control units

communicating via the CAN bus is de‐

fective.

Fault 01324

– Refer to control unit identification of ABS

with EDL control unit -J104- ⇒ page 8 and engine control unit to check that correct control units are installed.Allocation ⇒ Parts catalogue

trol unit ⇒ Motronic injection and ignition system; Rep. Gr. 01 , rectify fault if nec‐ essary and erase fault memory

– Check CAN bus wiring between engine

control unit and ABS with EDL control unit

-J104- ⇒ page 9

– Check CAN Bus wiring for interchanged

connections according to current flow di‐ agram

– Check CAN bus wiring ⇒ page 9

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

01324 Four-wheel drive control unit -J492No communication

14) Four-wheel drive vehicles only.

14)

♦ Faults in CAN bus wiring – Read measured value block 125

Fault 01423

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

01423 Lateral acceleration sender -G200Electrical fault in circuit

♦ Open circuit, loose circuit or short circuit

to positive or earth in wiring connection

going to lateral acceleration sender -

G200-

♦ Installation position of lateral accelera‐

tion sender -G200- not OK

⇒ page 115

– Check CAN bus wiring ⇒ page 9

– Perform electrical check, test step 19

⇒ page 130

– Check installation position ⇒ Brake sys‐

tem; Rep. Gr. 45

4. ABS/EDL/TCS/ESP ITT Mark 20 75

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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability

with respect to the correctness of information in this document. Copyright by AUDI AG.

Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

♦ Lateral acceleration sender -G200- de‐

fective

01423 Lateral acceleration sender -G200Implausible signal

♦ Installation position of lateral accelera‐

tion sender -G200- not OK

♦ Lateral acceleration sender -G200- de‐

fective

Fault 01435

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

01435 Brake pressure sender 1 -G201Electrical fault in circuit

♦ Open circuit, loose circuit or short circuit

to positive or earth in wiring connection going to brake pressure sender 1 -G201-

– Read measured value block 004

⇒ page 114

– Renew sender ⇒ Brake system; Rep. Gr.

45 , then perform zero compensation in basic setting ⇒ page 93

– Check installation position ⇒ Brake sys‐

tem; Rep. Gr. 45

– Read measured value block 004

⇒ page 114

– Renew sender ⇒ Brake system; Rep. Gr.

45 , then perform zero compensation in basic setting ⇒ page 93

– Perform electrical check, test step 21

⇒ page 131

♦ Brake pressure sender 1 -G201- defec‐

tive

Fault 01542

Display on -

VAS 5051 A-

01542 Yaw rate sender -G202Electrical fault in circuit

♦ Open circuit in earth connection to yaw

rate sender -G202-

♦ Installation position of yaw rate sender -

G202- not OK

♦ Yaw rate sender -G202- defective – Read measured value block 004

– Read measured value block, display

group 005 ⇒ page 114

– Renew sender ⇒ Brake system; Rep. Gr.

45 , then perform zero compensation in basic setting ⇒ page 95

Possible cause of fault Fault remedy

– Perform electrical check, test step 20

⇒ page 130

– Check installation position ⇒ Brake sys‐

tem; Rep. Gr. 45

⇒ page 114

– Renew sender ⇒ Brake system; Rep. Gr.

45 .

76 Rep. Gr.01 - Self-diagnosis, electrical checks

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permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability

with respect to the correctness of information in this document. Copyright by AUDI AG.

Fault 65535

Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

Display on -

Possible cause of fault Fault remedy

VAS 5051 A-

65535 Control unit defective

♦ Control unit defective – Remove hydraulic control unit, renew

4.7 Final control diagnosis

The final control diagnosis can be used to check the ABS hy‐ draulic pump -V64- and the correct functioning of the hydraulic circuits (allocation of brake pipes to wheel brakes and function of valves). This function will also detect interchanged connections and leaks.

Note

♦

The vehicle must be raised until all wheels are free to turn.

♦

To avoid overloading the control elements they are only acti‐ vated for a period of 60 or 90 seconds. The final control test will be terminated if the → key is not pressed within this period.

control unit ⇒ Brake system; Rep. Gr. 45 , then code control unit ⇒ page 103

Do not erase fault memory of old control unit. The data in the fault memory will help to identify the malfunction

♦

The ABS warning lamp -K47- and the red “brake warning” symbol flash during the final control diagnosis.

♦

After depressing the brake pedal several times the vacuum in the brake servo will be exhausted. Therefore more pressure must be applied to the brake pedal in order to attain the same fluid pressure in the brake system as that attained with vac‐ uum.

♦

When vacuum in brake servo is exhausted it can happen that the wheels do not lock: start engine and build up vacuum in brake servo.

Meaning of abbreviations indicated on display

IFL = Inlet valve

OFL = Outlet valve

VBAT = Battery voltage; voltage at valve

0V = 0 Volt; No voltage at valve

Hydr-P = ABS hydraulic pump -V64-

4. ABS/EDL/TCS/ESP ITT Mark 20 77

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Components of the ABS/EDL system

The hydraulic circuit is a schematic diagram of the ABS/EDL sys‐ tem. The diagram shows only one brake circuit.

1 - Low pressure accumulator

2 - ABS hydraulic pump -V64-

3 - EDL inlet valve (hydraulic)

4 - Noise damping chamber

5 - EDL change-over/separating valve (electrical) with integra‐

ted pressure limiting valve

6 - Front inlet valve

7 - Front outlet valve

8 - Front wheel

9 - Rear inlet valve

10 - Rear outlet valve

11 - Rear wheel

Test condition

• The wheels are locked individually during final control diagno‐ sis. For this test the mechanical and hydraulic components of the brake system must be working properly. This means that the master cylinder is able to build up pressure in all four wheel brake cylinders and there are no leaks in the hydraulic pipes, hoses and connections.

Note

If one of the wheels does not lock, perform a visual inspection of the brake fluid reservoir, the master cylinder, the hydraulic unit and the wheel cylinders.

Procedure

– Connect vehicle diagnostic, testing and information system -

VAS 5051 A- ⇒ page 7 and select vehicle system “03 - Brake electronics”. When doing this the ignition must be switched on.

Indicated on -VAS 5051 A- :

– Release handbrake.

– Raise vehicle on lifting platform.

– From list -1- select function “03 - Final control diagnosis”.

78 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

A - Final control test waiting, move on to next control element

1 - ABS hydraulic pump V64

– Touch → key.

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

1 - ABS hydraulic pump V64

• The ABS hydraulic pump -V64- - item 2- should start up audi‐ bly.

Note

♦

When you put your foot on the brake pedal you can feel it vi‐ brating. This is because the hydraulic pump -V64- is producing pressure pulses in the brake pipes. The pressure pulses in‐ duce the vibrations that can be felt at the brake pedal.

♦

The pressure pulses in the brake pipes are not sufficient to lock the wheels.

Audi TT 1999 ➤

– Touch → key.

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

2 - Operate brakes

– Depress brake pedal and and touch → within 10 seconds.

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

3 - IFL: 0V OFL: 0V Wheel FL locked

4. ABS/EDL/TCS/ESP ITT Mark 20 79

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

• Brake pedal must not give.

• When you press the brake pedal, brake fluid pressure will be built up in all four wheel brake cylinders.

• The hydraulic EDL valve -3- closes, the front wheels -8- and rear wheels -11- are locked.

Note

This test step in the final control diagnosis corresponds to the“pressure build-up” phase during ABS-controlled braking.

– Touch → key.

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

4 - IFL: VBAT OFL: 0V Wheel FL locked

– Keep pressing the brake pedal.

• The hydraulic EDL valve -3- remains closed.

• The front inlet valve -6- is activated, which interrupts the supply to the wheel brake cylinder; however, the fluid pressure is still maintained in the wheel cylinder.

• The front left wheel -8- remains locked.

Note

This test step in the final control diagnosis corresponds to the“maintain pressure” phase during ABS-controlled braking.

– Touch → key.

80 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

5 - IFL: VBAT OFL: VBAT Wheel FL free to turn

– Keep pressing the brake pedal.

• The inlet valve -6- and the outlet valve -7- for the front left wheel -8- are activated.

• The ABS hydraulic pump -V64- -item 2- starts running and re‐ duces the brake fluid pressure in the wheel brake cylinder via the open outlet valve.

• The brake pedal must not give, and should press back harder against your foot.

• The front left wheel -8- is free to turn.

Audi TT 1999 ➤

Note

♦

This test step in the final control diagnosis corresponds to the“pressure reduction” phase during ABS-controlled braking.

♦

If you cannot turn the front left wheel, check whether the brake line for the front left wheel is correctly connected.

♦

If this is the case, this indicates that there is a mechanical fault in one of the valves, providing that there is no electrical fault in the system. Renew the hydraulic control unit ⇒ Brake sys‐ tem; Rep. Gr. 45 .

♦

If the brake pedal gives under your foot, this means that the inlet valve or the non-return valve connected in parallel with the inlet valve is leaking. Renew the hydraulic control unit ⇒ Brake system; Rep. Gr. 45 .

– Touch → key within the next 10 seconds.

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

6 - IFL: VBAT OFL: 0V Wheel FL free

4. ABS/EDL/TCS/ESP ITT Mark 20 81

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

– Keep pressing the brake pedal.

• The hydraulic EDL valve -3- remains closed.

• The ABS hydraulic pump -V64- - item 2- should stop running.

• Only the inlet valve -6- is now activated, and this interrupts the supply to the wheel brake cylinder.

• The front left wheel -8- is free to turn.

Note

If the wheel is not free to turn, this means that the inlet valve or the non-return valve connected in parallel with the inlet valve is leaking. Renew the hydraulic control unit ⇒ Brake system; Rep. Gr. 45 .

– Touch → key.

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

7 - IFL: 0V OFL: 0V Wheel FL locked

– Keep pressing the brake pedal.

• The inlet valve -6- is no longer activated and does not interrupt the supply to the wheel brake cylinder.

• Brake pedal will give perceptibly under your foot.

• Brake fluid pressure is built up again in the front left wheel cylinder -8- - the wheel is locked.

– Touch → key.

82 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

8 - Release brakes

– Release brake pedal.

– Touch → key.

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

9 - Operate brakes

Note

♦

Continue the final control diagnosis to check the front right, rear left and rear right wheels in turn.

♦

The test steps are the same as for the front left wheel, so they are not described in detail.

Audi TT 1999 ➤

After testing on rear right wheel is completed:

– Touch → key.

Indicated on -VAS 5051 A- :

A - Final control diagnosis running, moving on permitted

30 - EDL valves/Hyd-P: VBAT FL/FR wheel locked

4. ABS/EDL/TCS/ESP ITT Mark 20 83

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

• The EDL change-over valve -5- and the EDL inlet valve -3- are activated.

• The ABS hydraulic pump -V64- - item 2- should start running for one second. The pump draws brake fluid out of fluid res‐ ervoir via EDL inlet valve.

• The hydraulic pump builds up brake fluid pressure in the EDL controlled wheel brake cylinders. The front left and front right wheels -8- are locked.

Note

If the front wheels are not locked, this indicates that there is a mechanical fault in one of the valves, providing that there is no electrical fault in the system. Renew the hydraulic control unit ⇒ Brake system; Rep. Gr. 45 .

– Touch → key.

Indicated on -VAS 5051 A- :

A - Final control diagnosis competed

– Terminate function “03 - Final control diagnosis” by pressing

the ← key.

• Final control diagnosis is completed. The ABS warning lamp

-K47- and the red “brake warning” symbol should go out.

Note

♦

There is a fault in the system if the ABS warning lamp -K47does not go out.

♦

Adhere exactly to the test sequence: First interrogate fault memory, then erase.

4.8 Basic setting

The function “04 - Basic setting” can be used to perform the fol‐ lowing procedures:

♦ Bleeding brake system if brake fluid reservoir has run dry

⇒ page 85 . Basic setting is only necessary if one or more of

the chambers in the brake fluid reservoir has been completely emptied (e.g. leaks in brake system).

♦ Function test of brake pressure solenoid -N247- and brake

pressure solenoid trip switch -F84- in display group 031

⇒ page 87

♦ Only four-wheel drive vehicles: switching off longitudinal ac‐

celeration sender -G251- via display group 040 ⇒ page 90 (e.g. to check the brake system on test rollers).

♦ Performing zero compensation of steering angle sender -G85-

in display group 060 ⇒ page 91 , e.g. after removing steering wheel, after performing adjustment on the running gear during wheel alignment and after renewing the following components: ABS with EDL control unit -J104- , steering angle sender G85- , steering column, or if zero compensation is required according to fault tables.

♦ Performing zero compensation of lateral acceleration sender

-G200- in display group 063 ⇒ page 93 , e.g. after renewing the following components: ABS with EDL control unit -J104-

84 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

and lateral acceleration sender -G200- , or if zero compensa‐ tion is required according to fault tables.

♦ Performing zero compensation of brake pressure sender 1 -

G201- and brake pressure sender 2 -G214- in display group 066 ⇒ page 95 , e.g. after renewing the following compo‐ nents: ABS with EDL control unit -J104- , brake pressure sender 1 -G201- , brake pressure sender 2 -G214- , or if zero compensation is required in fault tables.

♦ Only four-wheel drive vehicles: performing zero compensation

of longitudinal acceleration sender -G251- in display group 069 ⇒ page 97 (e.g. after renewing the following compo‐ nents: ABS with EDL control unit -J104- or longitudinal accel‐ eration sender -G251- ).

4.8.1 Bleeding brake system when brake fluid reservoir has been completely emptied

Basic setting is only necessary if one or more of the chambers in the brake fluid reservoir has been completely emptied (e.g. leaks in brake system).

Special tools and workshop equipment required

♦ Brake charge and bleed equipment -VAS 5234- or upgrade kit

and extraction unit -V.A.G 1869 A-

Audi TT 1999 ➤

Caution

♦ When using brake charge and bleed equipment -VAS

5234- to replenish the brake fluid, make sure that filling pressure does not exceed 1 bar.

♦ If the filling pressure exceeds 1 bar, a hydraulically con‐

trolled change-over valve for the EDL function prevents unrestricted flushing of the EDL-related parts of the hy‐ draulic unit. Proper bleeding is then no longer ensured.

♦ For this reason the brake fluid pressure must be reduced

to 1 bar on the brake charge and bleed equipment ⇒ Op‐ erating Manual -VAS 5234- or -V.A.G 1869 A-

♦ The charge and bleeder unit -V.A.G 1238/B- is not suitable

for bleeding the brake system by using the function “04 Basic setting”.

Note

If only charge and bleeder unit -V.A.G 1238/B- is available, switch the unit on and off as necessary to ensure that sufficient brake fluid is always present in the reservoir.

4. ABS/EDL/TCS/ESP ITT Mark 20 85

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Procedure

– Connect vehicle diagnostic, testing and information system -

VAS 5051 A- ⇒ page 7 and select vehicle system “03 - Brake electronics”. When doing this the ignition must be switched on.

– Connect brake charge and bleed equipment -VAS 5234- or -

V.A.G 1869 A- .

– Open bleed screws in prescribed sequence and pre-bleed

brake calipers.

1 - Simultaneously bleed both front left and front right brake cali‐ per

2 - Simultaneously bleed both rear left and rear right brake caliper

– With bleeder bottle hoses attached, leave bleed screws open

until the brake fluid emerges free from bubbles.

Bleeding

Indicated on -VAS 5051 A- :

– From list -1-, select function “04 - Basic setting”.

Indicated on -VAS 5051 A- :

1 - Enter display group

– Use keypad -2- to enter “001” for “Display group number 001”

and confirm by pressing the Q key.

• The ABS warning lamp -K47- flashes.

Indicated on -VAS 5051 A- :

1 - Basic setting

2 - Display group 1

3 - Press and hold pedal ...

– Press pedal with substantial foot pressure and hold.

• Pedal moves down, hydraulic pump starts up briefly, pedal comes back

Indicated on -VAS 5051 A- :

1 - Release pedal; FR/FL bleeder screws OPEN <>

– Release pedal, open front bleed screws.

– Press ↑ key to switch to display group 002.

86 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

1 - Basic setting

2 - Display group 2

3 - Please wait ... (10 secs.)

– Wait 10 seconds.

• Hydraulic pump starts up briefly

Indicated on -VAS 5051 A- :

1 - Press pedal 10X; bleed screws CLOSED <>

– Press pedal 10 times, close front bleed screws.

– Press ↑ key to switch to display group 003.

Indicated on -VAS 5051 A- :

1 - Basic setting

2 - Display group 3

3 - Press and hold pedal ...

– Repeat bleeding procedure as described above.

– Press the ↑ key in each case to switch to next highest display

group until display group 017 is reached.

Audi TT 1999 ➤

Indicated on -VAS 5051 A- :

1 - Basic setting

2 - Display group 17

3 - Part bleeding ended ...

– Terminate function “04 - Basic setting” by pressing the ← key.

– The brake system must now be bled ⇒ Brake system; Rep.

Gr. 47 .

4.8.2 Function test of brake pressure solenoid

-N247- and brake pressure solenoid trip switch -F84-

The function test is required if the brake servo is renewed, or if the test is required in the fault tables.

Procedure

– Connect vehicle diagnostic, testing and information system -

VAS 5051 A- ⇒ page 7 and select vehicle system “03 - Brake electronics”. When doing this the ignition must be switched on.

4. ABS/EDL/TCS/ESP ITT Mark 20 87

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

– From list -1-, select function “04 - Basic setting”.

Indicated on -VAS 5051 A- :

1 - Enter display group

– Use keypad -2- to enter “031” for “display group number 031”

and confirm by pressing the Q key.

• The ABS warning lamp -K47- flashes.

Indicated on -VAS 5051 A- :

A - Basic setting

B - Display group 31

1 - Solenoid active

– Press ↑ key to switch to display group 032.

Indicated on -VAS 5051 A- :

A - Basic setting

B - Display group 32

1 - 9.13 bar

2 - 7.43 bar

3 - Not operated

– Do not press brake pedal.

– Press ↑ key to switch to display group 033.

88 Rep. Gr.01 - Self-diagnosis, electrical checks

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Indicated on -VAS 5051 A- :

A - Basic setting

B - Display group 33

1 - Press and hold pedal ...

– Press pedal with substantial foot pressure and hold.

• The brake lights must be on.

– Press ↑ key to switch to display group 034.

Indicated on -VAS 5051 A- :

A - Basic setting

B - Display group 34

1 - 86.27 bar

2 - 7.43 bar

3 - Operated

– Press ↑ key to switch to display group 035.

Audi TT 1999 ➤

Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

A - Basic setting

B - Display group 35

1 - Release pedal

– Release brake pedal.

– Press ↑ key to switch to display group 036.

Indicated on -VAS 5051 A- :

A - Basic setting

B - Display group 36

1 - -0.85 bar

2 - -1.91 bar

3 - Not operated

– Press ↑ key to switch to display group 037.

4. ABS/EDL/TCS/ESP ITT Mark 20 89

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

A - Basic setting

B - Display group 37

1 - Solenoid test completed

– Terminate function “04 - Basic setting” by pressing the ← key.

4.8.3 Switching off longitudinal acceleration

sender -G251- (only vehicles with fourwheel drive)

♦ The longitudinal acceleration sender -G251- must be switched

off in display group 040 when checking the brake system of a four-wheel drive vehicle on test rollers.

♦ After completion of the check, the longitudinal acceleration

sender -G251- must be reactivated by switching the ignition off and back on again.

Procedure

– Connect vehicle diagnostic, testing and information system -

VAS 5051 A- ⇒ page 7 and select vehicle system “03 - Brake electronics”. When doing this the ignition must be switched on.

Indicated on -VAS 5051 A- :

– From list -1-, select function “04 - Basic setting”.

Indicated on -VAS 5051 A- :

1 - Enter display group

– Use keypad -2- to enter “040” for “display group number 040”

and confirm by pressing the Q key.

90 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

A - Basic setting

B - Display group 40

• The ABS warning lamp -K47- flashes.

The longitudinal acceleration sender -G251- is now deactivated.

– Terminate function “04 - Basic setting” by pressing the ← key.

– Select function “06 - End output” from list.

– After completion of the check, the longitudinal acceleration

sender -G251- must be reactivated by switching the ignition off and back on again.

4.8.4 Performing zero compensation of steer‐ ing angle sender -G85-

Perform zero compensation of steering angle sender after re‐ moving steering wheel, after performing adjustment on the run‐ ning gear during wheel alignment and after renewing the ABS with EDL control unit -J104- , the steering angle sender -G85- or the steering column, or if zero compensation is required in fault ta‐ bles.

Procedure

• Requirement: ABS with EDL control unit -J104- properly co‐

ded ⇒ page 103 .

– Start the engine.

– Turn the steering wheel approx. 60° to left or right and back

again until the front wheels are in straight-ahead position and the steering wheel is positioned horizontally (tolerance ± 4.5°).

– Perform short road test on a level surface. Drive in a straight

line and not faster than 20 km/h and observe the following points.

If the steering wheel is not horizontal:

– Make the necessary adjustments by checking wheel align‐

ment and fit steering wheel in correct position ⇒ Running gear, front-wheel drive and four-wheel drive; Rep. Gr. 44 , then perform zero compensation.

If the steering wheel is horizontal during the road test:

– Bring the vehicle to a standstill - still keeping it in a straight line.

• Do not change position of steering wheel!

• Do not switch off ignition!

– Connect vehicle diagnostic, testing and information system -

VAS 5051 A- ⇒ page 7 and select vehicle system “03 - Brake electronics”. When doing this the ignition must be switched on.

Audi TT 1999 ➤

4. ABS/EDL/TCS/ESP ITT Mark 20 91

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

– From list -1- select diagnostic function “11 - Login procedure”

or “11 - Coding II”.

Indicated on -VAS 5051 A- :

1 - Enter code word

– Use keypad -2- to enter code “40168” and confirm entry by

touching Q key.

Note

If display on -VAS 5051 A- reads “function unknown or function can not be performed at present” the login procedure or coding II were not successful. Repeat login procedure or coding II.

– Terminate function “11 - Login procedure” or “11 - Coding II”

by touching ← key.

Indicated on -VAS 5051 A- :

– From list -1-, select function “04 - Basic setting”.

Indicated on -VAS 5051 A- :

1 - Enter display group

– Use keypad -2- to enter “060” for “Display group number 060”

and confirm by pressing the Q key.

92 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

• The ABS warning lamp -K47- flashes.

Indicated on -VAS 5051 A- :

A - Basic setting

B - Display group 60

1 - Zero compensation OK

4 - 0.0°

Zero compensation of steering angle sender -G85- is now com‐ pleted.

– Terminate function “04 - Basic setting” by pressing the ← key.

Note

After pressing function “06 - End output” the ABS warning lamp K47- and the stabilisation program warning lamp -K155- light up for approx. two seconds.

Possible fault messages:

Indicated on -VAS 5051 A- :

1 - Zero compensation is not possible

4 - 12.3°

The determined value is outside the tolerance range for zero compensation.

– Proceed as follows to rectify the fault:

1. Check zero position of steering angle sender -G85- in meas‐

ured value block 004 ⇒ page 114 .

2. Interrogate fault memory ⇒ page 65 .

3. Erase fault memory ⇒ page 102 .

4. Conclude the transfer of data with the function “06 - End

output”.

5. Switch off ignition.

6. Switch ignition on again.

7. Perform zero compensation again.

Audi TT 1999 ➤

4.8.5 Performing zero compensation of lateral acceleration sender -G200-

Zero compensation must be performed if the ABS with EDL con‐ trol unit -J104- or the lateral acceleration sender -G200- were renewed, or if required by the fault table.

Procedure

• Vehicle is standing horizontal on a flat base.

– Connect vehicle diagnostic, testing and information system -

VAS 5051 A- ⇒ page 7 and select vehicle system “03 - Brake electronics”. When doing this the ignition must be switched on.

4. ABS/EDL/TCS/ESP ITT Mark 20 93

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

Indicated on -VAS 5051 A- :

– From list -1- select diagnostic function “11 - Login procedure”

or “11 - Coding II”.

Indicated on -VAS 5051 A- :

1 - Enter code word

– Use keypad -2- to enter code “40168” and confirm entry by

touching Q key.

Note

If display on -VAS 5051 A- reads “function unknown or function can not be performed at present” the login procedure or coding II were not successful. Repeat login procedure or coding II.

– Terminate function “11 - Login procedure” or “11 - Coding II”

by touching ← key.

Indicated on -VAS 5051 A- :

– From list -1-, select function “04 - Basic setting”.

Indicated on -VAS 5051 A- :

1 - Enter display group

– Use keypad -2- to enter “063” for “display group number 063”

and confirm by pressing the Q key.

94 Rep. Gr.01 - Self-diagnosis, electrical checks

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Running gear, self-diagnosis - Edition 07.2004

• The ABS warning lamp -K47- flashes.

Indicated on -VAS 5051 A- :

A - Basic setting

B - Display group 63

1 - Zero compensation OK

4 - 0.6 m/s

2

Zero compensation of lateral acceleration sender -G200- is now completed.

Note

The display does not return to 0.00 m/s2 after performing zero compensation successfully.

– Terminate function “04 - Basic setting” by pressing the ← key.

Note

Audi TT 1999 ➤

After pressing function “06 - End output” the ABS warning lamp K47- and the stabilisation program warning lamp -K155- light up for approx. two seconds.

Possible fault messages:

Indicated on -VAS 5051 A- :

1 - Zero compensation is not possible

4 - 5.0 m/s

2

The determined value is outside the tolerance range for zero compensation.

– Proceed as follows to rectify the fault:

1. Check zero position of lateral acceleration sender -G200- in

measured value block 004 ⇒ page 114 .

2. Interrogate fault memory ⇒ page 65 .

3. Erase fault memory ⇒ page 102 .

4. Conclude the transfer of data with the function “06 - End

output”.

5. Switch off ignition.

6. Switch ignition on again.

7. Perform zero compensation again.

4.8.6 Performing zero compensation of brake pressure sender 1 -G201- and brake pressure sender 2 -G214-

Zero compensation must be performed if the ABS with EDL con‐ trol unit -J104- , brake pressure sender 1 -G201- or brake pres‐ sure sender 2 -G214- were renewed, or if required by the fault tables.

Procedure

• Brake pedal not depressed.

4. ABS/EDL/TCS/ESP ITT Mark 20 95

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Audi TT 1999 ➤ Running gear, self-diagnosis - Edition 07.2004

– Connect vehicle diagnostic, testing and information system -

VAS 5051 A- ⇒ page 7 and select vehicle system “03 - Brake electronics”. When doing this the ignition must be switched on.

Indicated on -VAS 5051 A- :

– From list -1- select diagnostic function “11 - Login procedure”

or “11 - Coding II”.

Indicated on -VAS 5051 A- :

1 - Enter code word

– Use keypad -2- to enter code “40168” and confirm entry by

touching Q key.

Note

If display on -VAS 5051 A- reads “function unknown or function can not be performed at present” the login procedure or coding II were not successful. Repeat login procedure or coding II.

– Terminate function “11 - Login procedure” or “11 - Coding II”

by touching ← key.

Indicated on -VAS 5051 A- :

– From list -1-, select function “04 - Basic setting”.

Indicated on -VAS 5051 A- :

1 - Enter display group

– Use keypad -2- to enter “066” for “display group number 066”

and confirm by pressing the Q key.

96 Rep. Gr.01 - Self-diagnosis, electrical checks