Audi A4 2001 User Manual
254
Service.
AUDI A4´01 - Technical Features
Design and Function
For internal use only.
Self-study programme 254
Advance by technology
The new Audi A4,
a vehicle which combines driving pleasure and good sense
with the highest level of quality and sports styling.
Control unit for vehicle electrical system
New engine programme
...18
Electronic stability programme with
brake assistance
...32
Steering column switch module
Crash sensors for front airbag
...48
...44
...14
Trapezium link
rear axle
...27
Aero-floor
2
...7
Multi-communication bar
...72
Contents
Page
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Occupant protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Engine and gearbox
2.0 l R4 and 3.0 l V6 engines (see SSP 255) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Innovations - 2.5 l V6 TDI engine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Innovations - automatic gearbox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Running gear
Axles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Mechanical unit mountings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Brake system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Brake assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Electrical system
Vehicle electrical system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
CAN BUS system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Dash panel insert . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Steering column switch module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..44
Function circuit diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Control unit for vehicle electrical system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Function circuit diagram for "lowline" version . . . . . . . . . . . . . . . . . . . . . 50
Function circuit diagram for "highline" version . . . . . . . . . . . . . . . . . . . . 52
Convenience system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Anti-theft alarm system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Radio - chorus II, concert II and symphony II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Navigation IV and Navigation Plus-D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Multi-communication bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Electric logbook "Audi Logbook" . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Heater/AC
Design and function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
7-piston compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Air conditioner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Glove compartment cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Solar roof. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Fresh air blower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Actuators/sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Functional diagram for fully automatic air conditioner . . . . . . . . . . . . . . 84
Additional heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
The self-study programme will provide you with information on
design and functions.
It is not intended as a workshop manual.
For maintenance and repair operations it is essential that you
refer to the current technical literature.
New
Important:
Note
3
Introduction
The architecture of motion
Performance and smooth running
The engine programme of the new Audi A4
includes two petrol engines of a completely
new design, with aluminium housings.
The 2.0 litre 4-cylinder in-line engine with
96 kW (130 PS) and the 3.0 litre V6 with
162 kW (220 PS) fulfil the EU 4 emissions
standard.
A high degree of running smoothness is
achieved via balancer shafts.
Infinitely variable perfection
For the first time in this vehicle class, Audi
offers the infinitely variable "multitronic"
automatic gearbox for all front-wheel drive
versions.
The new light alloy running gear
With the four-link front axle, each wheel is
controlled by four aluminium transverse links.
The pivot bearings are also made from the
same light alloy.
The trapezium link rear axle for the quattro
drive system is also used in the front-wheel
drive models of the Audi A4.
4
Finely-tuned aerodynamics
Despite the greater frontal area and the cooling air current for the air conditioner (standard), it was possible to improve the C
value
D
by 5 %, in comparison to its predecessor,
to 0.28.
A special feature is the so-called aero-floor,
which provides for optimal airflow on the
underside of the vehicle.
High safety standards
With a thoroughly optimised body design and
comprehensive safety equipment, the new
Audi A4 is able to comply with all current valid
safety standards, throughout the world.
Crash sensors for the front airbags integrated
directly into the bumper bar, improve occupant protection.
SSP254_048
Electronic stability programme (ESP)
including brake assistant
For the latest ESP generation, the hydraulic
brake assistant is an integral part of the
standard equipment.
It is intended to assist the driver by automatically increasing the brake pressure during
emergency braking.
Communication centre on wheels
With regard to infotainment, the new
Audi A4 leaves nothing to be desired.
4 different audio systems, 2 differently configured Navigation systems and a car phone
with voice operation are on offer.
5
Introduction
Vehicle dimensions of Audi A4´01
1628
1528
1766
977
799
1050
921 976
257
2650
870
303
901
106/110
1526
1937
1
5
9
445 L
471
976
4527
1000
1400
1357
1088
SSP254_051
6
The aero-floor
not only contributes to improved aerodynamics.
It was also possible to reduce the noise level
by approx. 3 dB (A).
Front-wheel drive
The aero-floor was designed so as to guarantee ground clearance and resistance to stone
impact and to prevent accumulation of dirt,
stones and snow.
Four-wheel drive quattro and V6 engine
Part of the additional costs generated by the
aero-floor could be compensated by dispensing with certain panelling components as
well as by dispensing with PVC protection of
the underside of the vehicle. The latter is of
advantage during recycling.
SSP254_053
The engine compartment noise insulation does not form part of the aerofloor.
7
Body
Front impact design features
The new Audi A4 is designed for optimal conformance with current crash requirements
and safety standards.
This could only be achieved by increasing the
body weight.
In order to reduce this additional weight to a
minimum, the proportion of light-weight
materials has been increased in comparison
to its predecessor.
The proportion of high-strength sheet metal
parts as well as the use of a total of 10 large
component "tailored blanks", contribute significantly to weight reduction.
Body rigidity has been increased by 45 % by
increasing the number of connection points
by 25 %.
– the straightened longitudinal member with
crash-optimised octagonal cross-piece
– the rigid and significantly wider bumper
cross-piece
– the integration of the member structures
into the passenger cell
– strength, rigidity and weight-optimised
suspension strut cross-piece
SSP254_054
Depending upon vehicle weight, performance and fuel consumption are the characteristics
which our customers can experience at first hand.
8
Side impact design features
In the floor area, the cell consists of three
large tailored blanks, which ensure a stable
connection between the front and rear of the
vehicle.
Weight-saving optimisation of deformation
characteristics in the event of a side impact
was achieved by the use of an aluminium
extruded profile in the sill.
“tailored blanks” are made-to-measure
sheet metal parts with varying material
thickness.
SSP254_055
SSP254_056
9
Body
w
w
Doors
The doors of the Audi A4 demonstrate a significantly increased rigidity due to the onepiece door shell construction.
For the first time, a so-called spray-on noise
insulation is used, which is sprayed on as
required and allows weight reduction for the
same effectiveness.
Noise insulation
SSP254_066
In addition, the doors have been fitted with a
second weatherseal. One weatherseal is fitted
to the door and the other is fitted to the body.
The new door concept permits a reduction in
the overall noise level of a further 3 dB (A) and
thus contributes to improving the aero-acoustics.
SSP254_067
The newly developed sub-frame is bolted to
the door shell via fitted bolts.
Roof
Roof trim strip
Door windo
seal
Door windo
Door trim
Door seal
Door frame
Door frame seal
SSP254_075
Emergency door locking
In the event of failure of the central locking,
e.g. due to power supply faults, each door can
be individually locked without using the lock
cylinder.
Firstly, with the door open, the cap must be
removed. Emergency locking is effected by
inserting the ignition key.
After the door has been closed, it is not possible to open it from the outside.
The door can be opened from the inside by
actuating the door release handle twice.
SSP254_069
Luggage compartment lid
The luggage compartment lid should always
be operated via the radio remote control.
The lock cylinder for the luggage compartment lid is integrated into the handle.
Continuous locking of luggage compartment
If the lock cylinder is in the horizontal position with the key removed, the luggage compartment lid is no longer included in the
central locking system. Opening is then only
possible via the centre unlocking button of
the radio remote control.
When the lock cylinder is in the vertical position, the lid is an integral part of the central
locking system.
SSP254_070
Manual unlocking and opening
is effected by turning the key to the left.
In this position, it is not possible to remove
the key, which must subsequently be returned
to the vertical position.
Thus, it is ensured that the luggage compartment lid is an integral part of the central locking system.
SSP254_071
SSP254_072
11
Occupant protection
Overview of system
J285/K75
J533
T16
J393
G 283
J162
N95
J220
J234
G 284
J526
K145
AIRBAG
OFF
N131
AIRBAG
AUS
E224
EIN
12
N277
G 256
G179
N199
N153
N201
N200
N154
N202
G180
N278
G 257
SSP254_029
To complement the comprehensive body
modifications, occupant protection has been
improved through the further development of
the familiar 8.4 airbag system.
The new generation bears the designation 8.4 E, where the E stands for
"extended".
The position of the sensors is selected so that
they are installed as near as possible to the
outer structure of the vehicle.
This enables quicker deceleration detection in
the event of an impact.
The system comprises driver/passenger airbags, front side airbags, optional rear side
airbags, SIDEGUARDS
®
, three point front seat
belts with ball tensioners and belt force limiters, three point rear outer seat belts, centre
lap belt (for fixed rear seat bench), Isofix preparation in rear of vehicle, and a total of 6
non-central accelerometers:
– 2 front impact crash sensors
– 2 driver/passenger side airbag crash sen-
sors, (in the B-pillar for side impact)
– 2 driver/passenger rear side airbag crash
sensors, (on the C-pillar for side impact)
The external sensors deliver digitised acceleration data to the airbag control unit, which is
then evaluated in the control unit and which
triggers the relevant restraint system components.
Key
E224 Key switch for switching off
passenger’s side airbag
G179 Side airbag crash sensor, driver’s
side (B-pillar)
G180 Side airbag crash sensor, passenger’s
side (B-pillar)
G256 Crash sensor for rear side airbag,
driver’s side
G257 Crash sensor for rear side airbag,
passenger's side
G283 Front airbag crash sensor, driver’s
side
G284 Front airbag crash sensor,
passenger’s side
J162 Heater control unit
J220 Control unit for motronic
J234 Airbag control unit
J285 Control unit with display unit in
dash panel insert
J393 Central control unit for convenience
system
J526 Control unit for telephone /
telematics
J533 Diagnosis interface for data bus
(Gateway)
K75 Airbag warning lamp
K145 "Airbag off" warning lamp,
passenger's side
N95 Airbag igniter, driver's side
N131 Airbag igniter 1, passenger's side
N153 Igniter for belt tensioner, driver's side
N154 Igniter for belt tensioner,
passenger's side
N199 Igniter for side airbag, driver’s side
N200 Igniter for side airbag, passenger's
side
N201 Igniter for rear side airbag,
driver’s side
N202 Igniter for rear side airbag,
passenger's side
N277 Igniter for airbag in B-pillar
(SIDEGUARD
®
), driver's side
N278 Igniter for airbag in B-pillar
(SIDEGUARD
®
), passenger's side
T16 Connector, 16-pin, diagnosis
connection
13
Occupant protection
Crash sensors for front airbag G283, 284
Both sensors for front impact detection function in conjunction with the crash sensor and
the safe sensor which are integrated into the
airbag control unit J234.
If a certain signal threshold is exceeded in the
front airbag crash sensor, a threshold reduction is activated in the airbag control unit,
which results in a shorter triggering time.
Upper body
Head
Deceleration load
Impact
Belt force limiter
Front airbags inflated
Triggering of front airbags
Triggering of belt tensioners
Damping function
response in
response
Time [ms]
SSP254_058
the steering column
Vehicle rebound
SSP254_063
14
SSP254_064
Crash sensors for side airbags
G179, 180, 256, 257
In order to trigger the components of the
restraint system, two simultaneous impact
detection signals are required for the plausibility check:
– from both opposing crash sensors
(B-pillar left with right and/or
(C-pillar left with right) and
– from the control unit internal crash sen-
sors.
The crash sensors are designed in such a way
that incorrect installation is excluded.
Airbag control unit J234
The warning lamp for airbag K75 is activated
continuously following a detected impact.
"CRASH DATA STORED" and the triggered
components are displayed with fault code
during fault memory readout.
SSP254_059
Re-encoding of the airbag control unit is no
longer possible after the first crash data message is stored.
Triggering is performed in two thresholds
depending upon the deceleration value:
– Threshold 1 = belt tensioners only
– Threshold 2 = belt tensioners and airbag(s)
Sensors and components to be replaced
following an accident, are listed in the
current workshop manual.
15
Occupant protection
a
a
a
a
a
Deactivation of passenger airbag
Deactivation of the passenger airbag is only
possible via the key switch. In the Audi A4, the
passenger's side airbag is also deactivated.
Deactivation via the diagnostic tester is not
possible.
If a customer requires the deactivation function where a key switch is not fitted, this can
only be achieved by retrofitting the key switch
and airbag OFF lamp and by re-encoding of
the airbag control unit.
Front belt attachment
Belt lock and strap fastenings are permanently connected to the seat frame. Thus, in
conjunction with the seat belt height adjuster,
an optimal belt fitting can be achieved for
each seat position.
SSP254_101
SSP254_011
Front head restraints
In order to offer a high degree of occupant
protection in conjunction with the seat belt
and airbag, the front head restraints have
been supplemented by an integral locking
mechanism.
SSP254_102
16
Crash signal processing
There are two separate crash signal outputs:
One crash signal is output via the conventional wiring and triggers the following functions:
– Transmitting an emergency call via the
control unit for telephone/telematics J526
(optional)
– unlocking the vehicle,
– Switch on interior light
(switch must be set to door contact),
– switching on hazard warning lights via the
central convenience electronics J393.
The auxiliary heater J162 (optional) is
switched off by the central convenience
electronics J393 via a CAN convenience
message.
The second crash signal output functions via
the convenience CAN bus, which switches off
the engine fuel supply via the engine control
unit J220.
17
Engine and gearbox
Engine
The 4-cylinder, 2.0 l engine
provides high propulsive force due to the
maximum torque of 195 Nm at 3300 rpm.
SSP254_038
The 3,0 l V6 engine
with five-valve cylinder head, produces162 kW
(220 PS) at 6300 rpm from 2976 cm
The maximum torque of 300 Nm is developed
at 3200 rpm.
3
.
Torque [Nm]
Engine speed in rpm
Power output [kW]
SSP254_060
18
SSP254_030
Torque [Nm]
Engine speed in rpm
Detailed information on these engines
can be found in SSP 255.
SSP254_061
Power output [kW]
Innovations 2.5 l V6 TDI engine
SSP255_045
Technical data
Capacity: 2496 cm
Bore: 78.3 mm
Stroke: 86.4 mm
Compression: 18.5 : 1
3
Injection system: Bosch VE VP 44 S3.5
Turbocharger: VNT 20
Exhaust emissions class: EU 3
Consumption: urban 11.0 l/100 km
(6-gear, quattro) country 6.1 l/100 km
Power output: 132 kW (180 PS)
Torque: 370 Nm at 1500 rpm
The main features of the basic engine are the
same as those of the familiar V6 TDI engine
with 132 kW (180 PS).
Torque [Nm]
Engine speed in rpm
SSP255_039
Power output [kW]
average 7.8 l/100 km
The injection system was modified in order to
reduce exhaust gas and particle emissions.
Power output and torque curve values could
be maintained under conditions which were
well within EU 3 limit values.
Limit value [%]
NOx
HC+NOx
CO
EU 3 limit values 100 %
Particle = 0.05 g/km
CO = 0.64 g/km
HC+NOx = 0.56 g/km
NOx = 0.50 g/km
Particle
SSP255_038
19
Engine and gearbox
Injection pump VP 44 S3.5
Distributor bushing
Distributor shaft
Forced flush
return
Supply piston
Thermal shoulder
Forced flush feed
The high pressure section of the injection
pump has been redesigned with regard to
pressure levels and quicker solenoid valve
actuation.
The injection pressure at part throttle has
been increased by the following measures:
Solenoid valve
SSP255_040
In order to initiate pre-injection for cold and
warm engines, the solenoid valve dynamics
have been significantly increased.
The associated increased heat generation in
the solenoid valve, is compensated by
improved fuel flow and optimal filling of the
high pressure section is achieved.
– increased cam stroke from 3.5 to 4.0 mm
– more stable support structure for high
pressure section on pump body
– conversion from 3 pistons with a diameter
of 6.0 mm, to 2 pistons with a diameter of
7.0 mm.
By reducing the number of high-pressure pis-
tons from 3 to 2, it was possible to reduce
high-pressure leakage via the sealing sur-
faces.
20
Noise levels have been significantly improved
by the pre-injection for cold and warm operation and the use of dual-spring nozzle holders.
Previously, pre-injection via the solenoid
valve was only realised during the engine
warm-up phase.
Injector
For the first time, an ICU injector ( I nverse C avity U ndercut) is used, which has a dual needle
guide.
The advantage of this ICU geometry is a significantly improved spray formation, especially in the part throttle range for small
injection quantities and short needle lift.
Due to the improved spray formation through
the use of the ICU injector, it was possible to
reduce the exhaust emissions and the particle
values by up to 20 %.
ICU seat geometry
SSP255_041
Dual needle guide
ICU seat geometry Standard seat geometry
SSP255_042
21
Engine and gearbox
Charge air cooler
Through duct
Cooling duct section
The existing series connection of the two
charge air coolers for the 110 kW engine is
inadequate for the 132 kW engine with its
high air throughput.
A new charge air cooler design was devel-
oped, in order to ensure optimal charge air
flow.
22
SSP255_043
The charge air cooler design comprises two
sections, in which part of the charge air is fed
via a through duct, connected to a space-saving pipe, to the section of the other charge air
cooler which is fitted with cooling fins.
The rest of the charge air is fed directly
through the cooling fins, via a separate pipe,
to the second charge air cooler and into the
through duct.
Innovations - automatic
gearbox
5-speed 01V automatic gearbox
The Audi A4 quattro MJ01 with 5-speed automatic gearbox features a new shift lever gate,
together with a new shifting concept.
The existing selector lever positions, 4,3,2 are
discontinued and are replaced by the "S"
position.
Gearshift positions 4,3,2 have been discontinued as they are hardly ever used in practice.
The DSP (dynamic shift programme) and "tiptronic" function have basically rendered them
superfluous.
P
R
N
D
S
+
With the selector lever is in the "S" position, a
sports shift programme provides the relevant
driving dynamics. In position "S", the DSP
also provides for adaptation of the driving set
values to the driving conditions.
The introduction of the "S" programme enables a significant extension of the useful shift
range between economy and sports.
The "S" programme comprises the following
special features:
– If, during driving with constant accelerator
pedal position, the selector lever is set to
the "S" position, the system always shifts
down, within defined limits.
– In order to achieve a direct driving reaction
in response to accelerator pedal actuation,
the converter clutch is closed during driv-
ing operation, where possible.
– If, in conjunction with the overall gearbox
ratio, 5th gear is designed as overdrive
gear (overdrive, 4+E), only 1st -4th gears
are shifted.
SSP254_117
Example: Dynamics code 40
Shift map 1
We recommend the multi-function steering
wheel (available as optional extra) with steering wheel "tiptronic" ("thumb shifting").
Throttle valve angle [%]
Gearbox output speed [rpm]
D - normal driving programme
S - sports driving programme
SSP254_103
23
Engine and gearbox
"multitronic" and 5-speed automatic gearbox
An innovation for all automatic gearboxes is
the "Tip in D " function. This means that the
steering wheel "tiptronic" function is now
also available in selector lever position "D".
The transition to the "tiptronic" function is
effected by actuating one of the two tip
switches on the multi-function steering wheel
(selector lever in position "D"). The system
then switches to the "tiptronic" function for
approx. 10 seconds. All gears can be shifted
within the range of permissible engine
speeds.
The system returns to normal automatic oper-
ation approx. 10 seconds after the last tip
request.
SSP254_088
Special feature:
The countdown from approx. 10 seconds to
return to normal automatic operation is interrupted, in the event that cornering is detected
or the vehicle is in overrun operation.
When normal driving conditions are detected
again, the countdown recommences from
approx. 10 seconds.
24
Notes
25
Running gear
Axles
Four-link front axle
The thorough further development of the
light-weight construction resulted in a weight
reduction of approx. 8.5 kg at the front axle.
In addition to all transverse links, the pivot
bearing is now also made of aluminium.
The wheel bearing is attached to the pivot
bearing via four bolts. The wheel hub can be
pressed in and out.
Aluminium
spring plate
SSP254_086
Aluminium mounting bracket
Shock absorber valves
SSP254_087
Aluminium pivot bearing
The suspension strut mounting is of the bulky
rubber bearing construction.
It consists of two functional components:
– The inner part forms the connection to the
piston rod.
– The larger outer part provides for acoustic
insulation of the shock absorber.
26
SSP254_085
Trapezium link rear axle
The rear axle design with largely identical
components is used in both the front-wheel
drive as well as in the quattro versions.
SSP254_089
Toe adjustment
The front-wheel drive version is fitted with a
wheel bearing unit with integral wheel hub,
which is mounted on a stub axle forged
together with the wheel carrier.
Apart from the axle mounting, the two axle
versions differ only in the wheel carrier and
the wheel bearings.
Camber
adjustment
SSP254_091
Toe adjustment
The wheel bearings of the quattro version
consist of pressed-in, double-row angular ball
bearings with conventional wheel hubs.
SSP254_083
Camber
adjustment
SSP254_082
27
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