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Important:
Note
New
Contents
It is not intended as a workshop manual.
The self-study programme will provide you with information on
design and functions.
For maintenance and repair operations it is essential that you
refer to the current technical literature.
Page
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Occupant protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Engine and gearbox
Running gear
Axles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Mechanical unit mountings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Brake system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Brake assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
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 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
Electrical system
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The hazard warning flasher signal is control-
led separately by the vehicle electrical system
control unit, via the hazard warning flasher
button.
If, during hazard warning flashing, the turn
signal flasher is actuated, e.g. during towing,
the hazard warning lights lose their priority
for this period.
The turn signal clicking is generated by an
integral acoustic relay in the dash panel
insert.
Turn signal/hazard warning light control
The functions:
– Anti-theft alarm flasher
– Central locking system flasher when
opening/closing
– Key-learn flasher for key adaption
– Crash flasher
– Panic flasher (USA only)
are specified by the central convenience elec-
tronics and transmitted via the convenience
data bus to the vehicle electrical system con-
trol unit, which then executes the "com-
mands".
The signal for turn signal flashing or motor-
way flashing is output via the steering column
switch module and executed by the vehicle
electrical system control unit.
For active hazard warning flasher with
ignition OFF, the flasher bulbs are actu-
ated for a shorter period in order to mini-
mise current consumption.
Motorway flashing is detected by the vehicle
electrical system control unit when the turn
signal lever is pressed and this triggers a tri-
ple turn signal flash.
Turn signal light, right
Turn signal light, left
Turn signal light, right
Turn signal light, left
SSP254_077
SSP254_078
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In the basic version without rear electric win-
dow lifters, central locking control of the rear
doors is assumed by the central convenience
electronics.
Convenience system
The convenience system previously used in
the Audi A2 is also used in the Audi A4.
In the series version, the following additional
functions
– Door warning lights
– Radio remote control
and in the optional version, the following
functions
– Anti-theft alarm with interior monitor and
towing protection (new)
– Electric sliding/tilting/glass sun roof
– Footwell lights
– Exit lights
– Mirror fold-in function
– Mirror memory function
are included in the Audi A4.
Electrical system
Central convenience unit J393
Door control unit,
passenger’s side J387 Door control,
driver’s side unit
J386
Door control unit,
rear right J389
(optional) Door control unit,
rear left J388
(optional)
SSP254_132
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The following information and functions
are processed in the central convenience
electronics:
Crash signal
(from airbag control unit J234)
Handbrake switch F9
Tailgate release
– Button for release, tailgate lock
cylinder F248
– 3. Remote control button
– Switch for tailgate to F206
– Switch for central locking, tail-
gate F218
Anti-theft alarm (optional)
– Contact switch for bonnet F266
– Ultrasonic sensor for anti-theft
alarm G209
Aerial for remote control,
Central locking and anti-theft
alarm in multi-communication bar
Reversing lamp M17
When mechanical window lifters
fitted in rear
– Door contact signal
– Locking signal
– Safe signal
for rear doors
Fuel filler flap
– Motor for tank cap locking V155
Tailgate
– Motor for tailgate release V139
Anti-theft alarm (optional)
– Horn for anti-theft alarm H8
(sounder)
– Turn signal lights via data bus to
vehicle electrical system con-
trol unit J519
Interior light control
– Dimming of interior lighting
– Footwell light switching
(optional)
– Luggage compartment lamp
switching
Automatic closing/opening
– Window lifters via door control
units
– Sun roof
When mechanical window lifters
fitted in rear
– Lock rear door lock motors
– Safe rear door lock motors
– Activation of rear entry lights
(optional)
– Activation of rear door warning
lights
Enabling of door control units and
sunroof
Gateway function for diagnosis
– Control unit for vehicle electrical
system J519
– Steering column switch module
J527
Sensors Actuators Central convenience electronics (CCE)
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TS
Electrical system
The Audi A4 convenience system is available
with
– Anti-theft alarm
– Ultrasonic interior monitor
– Shattered glass sensor (Avant)
– Towing protection
as optional extras.
The anti-theft alarm is only activated when
the vehicle is locked via the radio remote con-
trol and by closing the driver's door.Deactivation is performed by
– opening the vehicle via the radio remote
control or
– opening the vehicle via the driver’s door
lock cylinder and switching on the ignition
within 15 seconds. If this time period is not
observed or if the key used is not stored in
the immobiliser, the alarm is triggered.
Data exchange between the immobiliser in
the dash panel insert and the central conven-
ience electronics takes place via the conven-
ience data bus.
Anti-theft alarm with interior monitor
High and low pitched tones
- air horn (sounder) Central control unit for con-
venience system J393Ignition steering
lock D Door lock
Convenience data bus
SSP254_133
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An innovation in the anti-theft alarm is that a
sounder with an integrated battery is fitted in
place of the horn.
This enables the alarm to sound even when
the power supply has been interrupted.
The ultrasonic interior monitor and the tow-
ing protection can be switched off from
inside the passenger compartment by means
of a switch.
Diagnostics
The angles of the both the longitudinal and
transversal inclination of the inclination sen-
sor are displayed in the measured value
block.
SSP254_134
SSP254_135
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Functional mechanism of inclination sender
Towing protection is achieved by means of
the inclination sender installed in the central
convenience electronics.
The functional mechanism of the inclination
sender is based on the determination of
resistance changes relating to the volumetric
fluctuation of a viscous electrically conduc-
tive fluid.
Electrical system
SSP254_110
The resistance is stored at the moment of
activation of the anti-theft alarm.
Changes in the position of the inclination
sensor caused by one-sided lifting of the
vehicle alter the resistance. The alarm is trig-
gered.
The angle of inclination can be displayed in
the measured value blocks.
Sub-com-
partment
Ceramic
housing
Indicator
fluid
Electrodes
Operational
amplifier
Variously arranged electrodes project into
this fluid.
Alternating fields are applied to the elec-
trodes of the sender, which is divided into
sub-compartments.
When a change in position occurs, the distri-
bution of the fluid in the chambers also
changes.
As the level of the liquid in the sub-compart-
ments changes, the resistance determined for
the sub-compartments via the electrodes also
changes.
Electrode
connections
SSP254_111