Audi A8 2002 User Manual

282

Service.

AUDI A8 ´03 - Technical Features

For internal use only

Self Study Programme 282

Complete vehicle information

The design and operation of the Audi A8 ´03 are described in the following Self Study Programmes:

SSP 283 – 6-speed automatic gearbox 09E in the Audi A8 '03 - Part 1 SSP 284 – 6-speed automatic gearbox 09E in the Audi A8 '03 - Part 2 SSP 285 – Running gear in the Audi A8 '03 SSP 286 – New data bus systems - LIN, MOST, Bluetooth SSP 287 – Audi A8 '03 - Electrical components SSP 288 – Audi A8 '03 - Distributed functions SSP 289 – Adaptive cruise control in the Audi A8 '03 SSP 292 – Adaptive air suspension in the Audi A8 '03 SSP 293 – Audi A8 '03 - Infotainment

Other helpful information on the Audi A8 ´03 can be found on the adjacent CD ROMs.

Electrical system CAN data bus 2

Contents

Page

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Passenger Protection

System layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Safety systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Engine, Mechanics

Technical data of V8 4.2 l 5V engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Technical data of V8 3.7 l 5V engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

System layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Electrohydraulic torque reaction support . . . . . . . . . . . . . . . . . . . . . . . . . 32

Exhaust system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Fuel tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Automatically controlled starting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Gearbox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Running Gear

Front axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Rear axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

4-level air suspension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

System layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Electric parking brake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Adaptive cruise control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Electrical System

Bus topology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Convenience and security electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Lighting system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Heating/Air Conditioner

Design and operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Operating principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Blower unit/air routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

System layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Block diagram for front air conditioner . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Block diagram for rear air conditioner . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

The Self Study Programme contains information on design features and functions.

The Self Study Programme is not intended as a Workshop Manual. Values given are only intended to help explain the subject matter and relate to the software version applicable at the time of SSP compilation.

Use should always be made of the latest technical publications when performing maintenance and repair work.

New

Attention Note

Introduction

The new Audi A8 is designed to replace its predecessor of the same name which achieved a total production ﬁgure of 105,092 since its introduction in June 1994. This was the ﬁrst standard saloon with aluminium body and epitomised a new philosophy in the luxury vehicle sector.

The weight-saving Audi Space Frame ASF represented a major breakthrough in terms of enhanced vehicle dynamics, whilst at the same time solving the problem of increasing weight.

Convenience/infotainment control via multimedia interface (MMI)

This body concept was further perfected in the Audi A2 and the design of the Audi A8 ´03 reﬂects the experience gained from both projects.

The aim when developing the Audi A8 ´03 was not merely to surpass its predecessor in terms of technical features and details.

Active head restraints for front seats

3.7 or 4.2 l V8 engine with intake manifold changeover function

Adaptive cruise control (ACC) with radar sensor in front bumper

Headlight with adaptive light function

As the Audi ﬂagship, the new Audi A8 is intended to symbolise the product identity of the next Audi generation.

An uncompromising sporty character, clearcut design, innovative technological systems and the highest possible quality level combine to provide an unforgettable driving experience.

In other words:

Automatic boot lid opening and closing function (optional)

Audi at its proverbial best.

LED-type tail lights

4-level air suspension

6-speed automatic gearbox 09E

Electric parking brake

"Advanced Key" entry and start authorisation system

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Body

Brief outline

976

1444

1629

1894

125

971 2944

5051

1615

2028

714

1136

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Kerb weight 1,780 kg Gross weight 2,380 kg

Turning circle 12 m Luggage compartment volume approx. 500 l

Tank capacity approx. 90 litres Drag coefﬁcient 0.27 C

Body

The Audi A8 ´03 sets new standards in its class by combining lightweight construction with outstanding stability. This is achieved through the use of innovative Audi Space Frame technology for the body design of the Audi A8. The technical progress reﬂected by the unique body concept stems from the consistent implementation of experience gained from the aluminium Audi A8 and A2 models.

Based on the ﬁndings obtained from these vehicles, it was possible to further reduce the number of body components and signiﬁcantly increase the level of automation in the production process as compared to the Audi A8 predecessor model.

The static torsional rigidity of the new Audi A8 body is 60 % higher than that of the previous Audi A8 body. A crucial contribution is made to the increased rigidity level by the advanced Audi Space Frame structure.

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Characteristic features of the new structure:

– Large castings with numerous integrated

functions and a high degree of joint strength

– IHF* sections – optimum cross sections at

all locations, for example at side of roof frame

– Sheet metal panels with high levels of local

rigidity thanks to the use of special technologies designed to achieve differing functional cross sections and structures

*IHF = Internal high-pressure forming

Body

A-pillar

The A-pillar is made of two cast shells connected by rivets and welds. The shells enclose the sill panel at the bottom and the continuous roof frame at the top.

Sill panel

Use is made for the sill panel of a 3-piece extruded section. The extruded section must be replaced in the event of sill panel damage. Depending on the nature of the damage, either the entire section has to be replaced or parts of it by way of three separating sleeves.

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Rear end

The rear end has been completely redeveloped. The two large central castings are the one connecting the sill panel/ longitudinal member and the C/D-pillar connecting element.

The sill panel/longitudinal member connecting element is the largest casting. It supports the entire rear sub-frame and links the rear longitudinal member to the sill panel. Its great rigidity is designed to protect the tank in between in the event of a rear-end collision.

The C/D-pillar connecting element (large upper casting) accommodates the suspension strut at the top and the seat belt at the front, in addition to forming the terminating side section of the roof frame.

The large upper and lower castings are interlinked by way of two straight extruded sections and form the framework for the air suspension strut holder.

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Large upper castings

Extruded sections

Large lower castings

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Body

Boot lid

Foam encasing

Electronic boot lid lock with microswitch

Motor for automatic closing aid

A standard feature is an automatic closing aid, which is actuated by a Bowden cable separately from the catch. After the latch has closed, a mechanism pulls the catch downwards, overcoming the build-up of pressure occurring. On locking, a microswitch in the boot lid lock transmits a signal to the control unit to activate the automatic closing aid.

cable

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CatchBowden

The drive unit is only encased in foam and inserted between side panel and battery.

Automatic boot lid

Hinge mechanism (open)

Boot lid control unit J605

Button in driver's door Button on boot lid Vehicle key

Pressing the button in the driver's door or on the boot lid, or remote control actuation, effects release and motor-driven opening of the boot lid. Automatic boot lid closing can only be implemented by way of the boot lid button.

An electric motor ﬂanged directly to the swivel joint of the right boot lid hinge opens or closes the boot lid.

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In the event of manual boot lid actuation, the electric motor is disconnected by way of a magnetic coupling, thus permitting the boot lid to be moved by hand. On closing the boot lid, the drive is deactivated via a microswitch at the latch and the automatic closing aid activated.

As a general rule, interruption of automatic actuation always causes the boot lid to be disconnected from the drive unit and thus set to manual mode.

Body

Front doors

The doors are made up of a combination of aluminium panels, aluminium sections and aluminium castings. Optimised rib geometry and wall thickness in the hinge and lock mounting castings formed the basis for ideal implementation of the lightweight construction concept.

Door shell and door frame are connected at the door pre-assembly stage by means of ﬁtted bolts to ensure the accurate assignment of both components. Window lifter frame, window lifter motor/gear mechanism, door control unit and speaker are pre-assembled on a base plate and bolted to the door subframe.

Rear doors

Large, high-strength side impact members are integrated into the door to provide even load distribution in the event of side impact.

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Seats

Backrest adjustment – The angle of the top 1/3 of the backrest can be adjusted by 15° for enhanced shoulder comfort.

Lumbar support with massage function over a length of 60 mm

Crash-active, electronic head restraint with 70 mm height adjustment

Thorax/pelvis side airbag

Backrest fan

Electric seat depth adjustment – As the structure moves forwards it pulls the padding with it and so extends the seat area by 50 mm.

A new seat concept was developed for the Audi A8 ´03. The basic seat features the following standard functions:

– Electric seat length, height and angle

adjustment – Electric backrest angle adjustment – Front crash-active head restraints (refer to

Page 21)

The basic seat can additionally be ﬁtted with

– Four-way lumbar support – Seat memory for driver and front

passenger – Electrically adjustable head restraints – Electric belt height adjusters

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Seat cushion fan

Extra features of sports and comfort seats:

– Electric top 1/3 backrest adjustment – Electric seat depth adjustment

Optional extras for comfort seat:

– Climate function (refer to Page 85) – and/or massage function

The massage function is implemented by way of rhythmic action of the electromechanical lumbar support, thus massaging and relaxing the back muscles.

The ﬁxed rear seat bench versions correspond to those of the front seats, with the third head restraint being fully retractable. Electric individual seats are however only available as "Basic" and "Comfort" versions.

Passenger Protection

System layout

J285/K75

T16

G 283

N95/G85

J623

J234

K145

AIRBAG

OFF

G 284

AIRBAG

AUS

E224

EIN

J533

N131

N251

G 256

G179

N199

N153

N201

E24 E25

J526

N196 N198 N197

N200

N154

N202

G180

N252

G 257

J393

J655

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Use is made in the Audi A8 ´03 of the 8.4E+ airbag system with the aim of attaining greater occupant safety whilst reducing the impact. This was achieved, for example, by way of twostage front airbag triggering, active front head restraints and a battery cut-off element.

Key

The wide range of sensors permits detection not only of head-on collision and side impact, but also of rear-end collisions.

E24 Driver side belt switch E25 Front passenger side belt switch E224 Airbag disabling key switch,

front passenger side

G85 Steering angle sender G179 Side airbag crash sensor,

driver side (B-pillar)

G180 Side airbag crash sensor,

front passenger side (B-pillar)

G256 Rear side airbag crash sensor,

driver side

G257 Rear side airbag crash sensor,

front passenger side

G283 Front airbag crash sensor,

driver side

G284 Front airbag crash sensor,

front passenger side

J234 Airbag control unit J285 Control unit with display

in dash panel insert

J393 Convenience system central

control unit J526 Telephone/telematics control unit J533 Data bus diagnostic interface

(gateway) J623 Engine control unit J655 Battery cut-off relay

K75 Airbag warning lamp K145 Airbag disabled warning lamp,

front passenger side

N95 Driver side airbag igniter N131 Airbag igniter 1, front passenger side N153 Belt tensioner igniter 1, driver side N154 Belt tensioner igniter 2,

front passenger side

N196 Rear belt tensioner igniter,

driver side

N197 Rear belt tensioner igniter,

front passenger side

N198 Rear belt tensioner igniter,

centre N199 Side airbag igniter, driver side N200 Side airbag igniter,

front passenger side N201 Rear side airbag igniter,

driver side N202 Rear side airbag igniter,

front passenger side N251 Curtain airbag igniter, driver side N252 Curtain airbag igniter,

front passenger side

T16 16-pin connector

(diagnostic connection)

Passenger Protection

Block diagram

J655

F138

G283 G284 G179

E224

J234

N95

Key

E24 Driver side belt switch E25 Front passenger side belt switch E224 Airbag disabling key switch,

front passenger side

F138 Airbag coil connector/return spring

with slip ring

G179 Side airbag crash sensor,

driver side

G180 Side airbag crash sensor,

front passenger side

G256 Rear side airbag crash sensor,

driver side

G257 Rear side airbag crash sensor,

front passenger side

G283 Front airbag crash sensor,

driver side

G284 Front airbag crash sensor,

front passenger side

N131

N202N199 N200 N201

J234 Airbag control unit J655 Battery cut-off relay

N95 Driver side airbag igniter N131 Airbag igniter 1, front passenger side N153 Belt tensioner igniter 1, driver side N154 Belt tensioner igniter 2,

front passenger side N196 Rear belt tensioner igniter, driver side N197 Rear belt tensioner igniter,

front passenger side N198 Rear belt tensioner igniter, centre N199 Side airbag igniter, driver side N200 Side airbag igniter,

front passenger side N201 Rear side airbag igniter,

driver side N202 Rear side airbag igniter,

front passenger side

G180

G256 G257 E24 E25

4 5 6 7

N251 Curtain airbag igniter, driver side N252 Curtain airbag igniter,

front passenger side

Colour code

= Input signal

= Output signal

= Positive supply

= Earth

N198N251 N252 N153 N154 N196 N197

Additional signals

Battery A (positive)

Positive connection to starter B and alternator C

Terminal 58s

Drive system CAN (High)

Drive system CAN (Low)

Crash signal

Airbag disabled warning lamp, front passenger side K145

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Passenger Protection

Safety systems

2-stage front airbags

The 2-stage triggering of the front airbags provides optimum restraint in crash situations at around 30 km/h. There is a separate ﬁring pellet for each stage in the driver's and front passenger's airbag. These ignite successively at speciﬁed time intervals.

Ring airbag

A so-called "ring airbag", which inﬂates like a life belt, is used on the driver's side. This radial inﬂation method affords particular protection to drivers sitting very close to the steering wheel. The centre of the steering wheel does not move as the airbag unfolds and is inﬂated in the form of a ring. A rectangular fabric layer is additionally sewn to three sides of the ring. One side is left free to allow the airbag to slide over the nonmoving centre section of the steering wheel.

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This airbag design satisﬁes the requirements of the latest American legislation and involves compliance with biomechanical values for so-called "Out Of Position" (OOP) driver posture. If the driver's head or upper part of the body is very close to the steering wheel at the time of airbag unfolding (OOP), this airbag concept can prevent serious injury.

Front passenger's airbag deactivation

An optional feature of the Audi A8 ´03 is a new airbag disabling key switch for the front passenger's side E224. Two resistance paths are integrated into this switch to permit detection of individual faults. A fault in the key switch is indicated by ﬂashing of the front passenger's side airbag disabled warning lamp K145 located in the centre console next to the hazard warning switch.

Front knee airbags (USA)

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The USA version of the Audi A8 ´03 is ﬁtted with driver's and front passenger's knee airbags as standard, thus optimising driver and front passenger movement in a crash situation.

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In this way, severe impact in the knee zone is avoided. Knee airbags are required by legislation in the USA.

Passenger Protection

Detection of rear-end collision

Rear-end collisions are detected by way of a sensor in the airbag control unit J234 and a plausibility function involving the driver's and front passenger's front airbag crash sensors G283 and G284.

Up-front sensors

For the ﬁrst time, use is made in the Audi A8 ´03 of so-called up-front sensors.

Lateral acceleration sensors

These take the form of two additional frontend acceleration sensors on the right and left beneath the corresponding headlight.

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Further acceleration sensors are located at the B and C-pillars.

C-pillar sensor B-pillar sensor

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Active head restraints

The front seats of the Audi A8 ´03 are provided with active head restraints. With this system, the head restraints move forwards in the event of a rear-end collision to shorten the distance between head and restraint.

The danger of cervical vertebrae injury is greatly diminished by reducing the relative acceleration between shoulder and head. In head-on collision situations, the mechanics of centrifugal weight are neutralised.

Belt tensioners

Five belt tensioners are ﬁtted as standard. There is no centre belt tensioner if the rear seats are electrically adjustable.

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Passenger Protection

Battery cut-off relay J655

The battery cut-off relay is a battery isolating element designed to disconnect starter and alternator power from the electrical system in the event of a crash.

Terminal Pin Input/output Description

30, battery A Input

(screw connection)

87 B Output

(screw connection)

Terminal 15 1 Input

(plug connection)

Vehicle earth 2 Input

(plug connection)

Crash signal 3 Input

(plug connection)

Diagnosis 4 Input

(plug connection)

Block diagram

J644 Energy management control unit J655 Battery cut-off relay

term. 30/battery

bat.

Output

Positive power supply,

interruptible

Earth from

airbag control unit J234

Crash signal from

airbag control unit J234

Diagnostic wire from

airbag control unit J234

J644

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J655

Fitting location

The battery cut-off relay is located in front of the battery.

Triggering

The airbag control unit J234 provides the battery cut-off element with the triggering command via a discrete wire. Triggering of this element by the airbag control unit causes a white panel to appear in the element window instead of a copper coil. Following isolation, the battery cut-off element can be manually reset by way of the yellow knob.

Control element test

The control element test in the airbag control unit also triggers the battery cut-off relay. It should be ensured that the relay is manually reset, as otherwise the battery cannot be charged.

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Reset knob

Window

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Engine, Mechanics

2000

4000

6000

406080

Technical data

V8 4.2 l 5V engine

Engine code letters: BFM

Capacity:

4,172 cm

460

440

Bore: 84.5 mm

Stroke: 93.0 mm

Compression ratio: 11 : 1

Power: 246 kW (335 hp)

at 6,500 rpm

Torque: 430 Nm at 3,500 rpm

Camshaft adjustment range: 22° CS advance

Valves: 5 per cylinder

Engine management: ME7.1.1

Emission standard: EU 4

420

400

380

360

340

320

Torque [Nm]

300

280

260

Power [kW]

Engine speed [rpm]

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Firing order: 1 - 5 - 4 - 8 - 6 - 3 - 7 - 2

Capacities: 7.5 l engine oil (incl. ﬁlter)

Consumption: Urban: 17.5 - 17.6 l/100 km

Non-urban: 8.7 - 8.8 l/100 km Average: 11.9 - 12.0 l/100 km

Acceleration 0 - 100 km/h: 0 - 80 km/h – 4.8 s

0 - 100 km/h – 6.3 s

Fuel: Premium Plus Unleaded

98/95 RON

CS = Crankshaft

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V8 3.7 l 5V engine

Engine code letters: BFL

Capacity:

3,697 cm

460

440

240

Bore: 84.5 mm

Stroke: 82.4 mm

Compression ratio: 11 : 1

Power: 206 kW (280 hp)

at 6,000 rpm

Torque: 360 Nm at 3,750 rpm

Camshaft adjustment range: 13° CS advance

Valves: 5 per cylinder

Engine management: ME7.1.1

Emission standard: EU 4

420

400

380

360

340

320

Torque [Nm]

300

280

260

Power [kW]

Engine speed [rpm]

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Firing order: 1 - 5 - 4 - 8 - 6 - 3 - 7 - 2

Capacities: 7.5 l engine oil (incl. ﬁlter)

Consumption: Urban: 17.1 - 17.3 l/100 km

Non-urban: 8.6 - 8.8 l/100 km Average: 11.7 - 11.9 l/100 km

Acceleration 0 - 100 km/h: 0 - 80 km/h – 5.6 s

0 - 100 km/h – 7.3 s

Fuel: Premium Plus Unleaded 98/95 RON

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Engine, Mechanics

V8 5V 3.7 l/4.2 l engine

The 3.7 l and 4.2 l V8 engines were adopted from the predecessor model with certain modiﬁcations.

These modiﬁcations relate to the intake and exhaust systems and are described in the following.

Variable-intake manifold in 4.2 l engine

This takes the form of a 2-stage variable-intake manifold made of a die-cast magnesium alloy, bonded and bolted together in four sections.

The two-stage design permits the use of two intake paths with large cross section.

Design and operation are described in SSP 217.

The intake manifold must be replaced as a complete unit when performing repairs.

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– Long intake path, 705 mm – Changeover ﬂap closed for high torque

Each of the two splined shafts is ﬁtted with four ﬂaps per cylinder bank. The shape of the rubber-encased ﬂaps ensures unimpeded air ﬂow in the torque position and reliable power position sealing of the duct. This is a prerequisite for utilisation of the gas-dynamic resonance effects. In the power position, the backs of the ﬂaps take on the shape of the duct wall, thus allowing low-resistance intake air ﬂow into the cylinders.

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Mechanical couplings provide a link with the vacuum units for adjustment of the two shafts and thus the intake manifold ﬂaps.

– Short intake path, 322 mm – Changeover ﬂap open for high power

with high air throughput

Changeover from long to short at 4,480 rpm Changeover from short to long at 4,320 rpm

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Engine, Mechanics

Variable-intake manifold in 3.7 l engine

Changeover ﬂap, stage 3

Vacuum unit Changeover ﬂap, stage 3

Vacuum unit Changeover ﬂap, stage 2

Intake air (inlet)

Changeover ﬂap, stage 2 (open)

Resonance tube, cyl. 5 (inlet end)

From electronic throttle

Throttle valve

Injector mounts

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This is the same 3-stage variable-intake manifold as previously ﬁtted in the V8 engine.

Operation of the 3-stage variable-intake manifold is described in SSP 217.

Due to the piston stroke of only 82.4 mm, three resonance tube lengths are required to achieve resonance effects in the lower engine speed range.

Changeover points:

– Long to short

at 3,280 rpm

– Short to long

at 3,120 rpm

– Short to shorter

at 5,120 rpm

– Shorter to short

at 4,920 rpm

Air cleaner

A round ﬁlter is employed instead of a ﬂat ﬁlter to achieve a larger ﬁlter surface area for more air throughput in view of the different amount of space available.

Furthermore, an additional intake air ﬂap in the air cleaner is opened as a function of load at engine speeds as of 3,000 rpm to attain the large volume of air required at full throttle. This ﬂap enables additional air to be drawn in from the engine compartment and reduces the air velocity in the air cleaner.

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+ 67 hidden pages