park AUDI A8 2003 D3 / 2.G Technical Features Manual

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Attention
NoteNew
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.

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SSP282_025
As the Audi flagship, the new Audi A8 is
intended to symbolise the product identity of
the next Audi generation.An uncompromising sporty character, clear-
cut design, innovative technological systems
and the highest possible quality level
combine to provide an unforgettable driving
experience.
In other words:
Audi at its proverbial best.Automatic boot lid opening
and closing function
(optional)
LED-type tail lights
4-level air suspension
Electric parking brake
"Advanced Key" entry and start authorisation system
6-speed automatic gearbox 09E

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Engine, Mechanics
Sequence of operations
1 Entry and start authorisation switch E415/entry and start authorisation button E408
2 Entry and start authorisation control unit J518
The entry and start authorisation control
unit checks for authorisation – in the form
of information on selector slide position N
or P – from the automatic gearbox control
unit J217 and for brake application in the
case of a start signal from the entry and
start authorisation button E408.
3 Engine control unit J623 Application of selector slide position P/N or
"clutch pressed" information to the engine
control unit (separate interface) causes the
two starter relays J53 and J695 to be
actuated simultaneously. The relays then
switch terminal 50 for starter actuation.
The starter operates and cranks the engine.
On exceeding a defined engine speed, the
engine control unit J623 recognises that
the engine has started and the relays are
deenergised (thus terminating starting
process).
As a safeguard, two relays are connected in
series. In the event of fusion welding of the
make contacts (relay remains closed
following deenergisation), the engine
control unit J623 can thus interrupt the
circuit (terminal 50) by way of the other
relay in each case.
The two relays are deenergised alternately
in order to ensure even make contact wear
(break spark) in both relays. The
deenergisation sequence alternates. The driver triggers a brief start signal
(min. 20 ms) by turning the ignition key to
start position or by pressing the entry and
start authorisation button E408.
If the start prerequisites have been
satisfied, the entry and start authorisation
control unit J518 transmits a start request
– terminal 50 ON – to the engine control
unit J623.
The entry and start authorisation control unit J518 also controls the terminal 15 and
terminal 75x circuits.
Relay operation is monitored and faults diagnosed by evaluating the alternating
deenergisation with the aid of the terminal
50R interface.
The terminal 50R interface represents a link
with terminal 50 and provides the engine
control unit J623 with feedback for start
control/diagnosis.
Automatically controlled starting is not
permitted in the event of undervoltage or a
system fault.
The engine can however be started
manually by way of corresponding start
signal actuation.
To relieve the load on the starter and
battery, the relay actuation time is
limited to approx. 10 seconds per starting
operation (automatic or manual starting).

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The following functions are provided by the
electric parking brake:
– Parking brake function
– Emergency braking function
– Holding function when driving off on a hill
– Brake pad wear indicator
Electric parking brake
The brake pads are applied by way of a
spindle mechanism.
Gear unit and motor are flanged to the brake
caliper.
Implementation of the parking brake function
involves translating the rotation of the drive
motor into a very short brake piston stroke.
This is achieved through the use of a swash
plate mechanism in combination with the
spindle mechanism.
The emergency braking function is initiated
via the parking brake button and transmitted
to all four wheels by the brake hydraulics.
Design and operation of the electric
parking brake are described in SSP 285.
SSP282_055
Toothed belt
Swash plate mechanismElectric motor Brake piston
SpindleElectrical connection
Brake disc Brake caliper

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Bus topology
Electrical System
The increasing demand for additional
functions and convenience in the vehicle calls
for the use of ever more wide ranging
electronics.
The increased use of electronics also requires
a new approach to data transfer between the
individual control units. This also applies to
the Audi A8 ´03, in which more than 70 control
units have to communicate.
Distance regulation
control unit J428
Electric park and
handbrake control
unit J540Headlight range
control unit
J431Airbag control unit
J234ABS with EDL
control unit
J104
Engine control unit
J623Adaptive
suspension control
unit J197 Engine control
unit 2 J624Automatic gearbox
control unit
J217
Anti-theft/
tilt system control
unit J529
Boot lid control unit
J605Wiper motor control
unit J400Garage door
operation control
unit J530 Multifunction
steering wheel
E221
Convenenience
system central
control unit J393On-board power
supply control unit
J519
On-board power
supply control unit 2
J520Steering column
electronics control
unit J527Steering angle
sender G85
Driver side door
control unit J386Front passenger
side door
control unit J387Rear left door
control unit J388Rear right door
control unit J389Seat adjustment
control unit
J136Front passenger
seat adjustment
control unit J521 Control unit with
display in dash panel
insert J285
Diagnostic connection T16
Dash panel insert CAN
Drive system CAN
Diagnosis CAN
Convenience CAN
Internal bus link
LIN
Adaptive cruise control
CAN

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Telephone/
telematics control
unit J526
Front information
display and operating
unit control unit J523Rear DVD changer
R162Telephone
handset
R37
Control unit for rear
left
information display
and operating
unit J648
DSP control unit
J525
Navigation system
control unit
J401
TV tuner
R78
Digital radio
R147
Radio module R Chip card reader
control unit
J676 CD changer
R41 CD ROM drive
R92 Data bus diagnostic
interface J533
Fresh-air blower
control unit
J126Heated windscreen
control unit J505Rear left footwell
heater element Z42Rear right footwell
heater element Z43Driver seat
ventilation
control unit J672Front passenger
seat ventilation
control unit J673

Parking aid control
unit J446 Entry and start
authorisation
control unit J518 Energy
management
control unit J644 Rear seat
adjustment with
memory control
unit J522 Climatronic control
unit J255
Trailer detector
control unit J345
Rear Climatronic
control and
display unit E265Tyre pressure
monitor control unit
J502
Sun roof electronics
control unit J528
Additional heater
control unit J364Driver identification
control unit J589
Auxiliary heating
radio controlled
receiver R64 Sliding sun roof
motor V1 Front passenger
side rear seat
ventilation
control unit J675 Driver side rear seat
ventilation control
unit J674 Control unit for rear
right
information display
and operating
unit J649
MOST busBluetooth
TM
LIN
LIN

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Electrical System
The headlight in the Audi A8 ´03 combines both
design elements and innovative technology.
Headlight versions:
– Basic halogen version H7
Dynamic headlight range control is not
necessary with halogen headlights. The air
suspension provides compensation for static
load statuses and a thumbwheel is therefore
also not required.
– Bi-xenon version
– Bi-xenon version with integrated adaptive
light function
The headlight range control unit J431 is
responsible for providing static and dynamic
compensation for vehicle tilting as well as
actuation of the static adaptive light
function. The sensor signals of the 4-level air
suspension system are picked off by the
drive system CAN for control purposes. A
distinction is made between the two
gas-discharge lamp versions by way of
appropriate encoding (1 or 2) at the
headlight range control unit.
Lighting system
Front lights
SSP282_056
HPV stands for high-performance bulbs,
which are extremely compact and have a far
longer service life. They have a 25 % lower
power input than conventional bulbs. Such
bulbs cannot be replaced by customers.
Both bi-xenon versions feature an ellipsoid
module with a moving screen to achieve both
dipped beam and main beam with xenon light.
The automatic dynamic headlight range control
represents a more advanced version of the
standard automatic control system. It provides
headlight tilt compensation not only for various
load statuses but also as a dynamic function
reacting to differences in running gear
inclination caused by acceleration and
deceleration.
Dipped beam/main beam
(Bi-Xenon/D2S - gas-discharge lamp)Turn signal indicator
(2 x 16 W HPV bulb - yellow) Parking light
(W5W/5 W bulb)Adaptive light
(H8/35 W bulb)
Additional main beam
Headlight flasher
(H7/55 W bulb)Reflector
for adaptive light

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Light functions
SSP282_087
Adaptive light
The additional reflector with a 35 W H8
halogen bulb is actuated as the situation
requires to ensure earlier perception of other
road users or obstacles.
When reversing or parking, both adaptive
lights are activated to provide the driver with a
better overall view of the surrounding area.
Adaptive light
Control of the headlight functions is a complex
process.
It involves real time evaluation of several
signals (e.g. vehicle speed, steering angle and
turn signal indicator) by the headlight range
control unit J431.
SSP282_092
The optional headlights with adaptive light
function are a clearly visible innovative feature
in the Audi A8 ´03. To implement this function,
the headlights are provided with an additional
reflector between dipped beam and main
beam.

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Electrical System
Side lights
This is the first Audi vehicle to be fitted with
LED-type lights. The individual LEDs are fitted
in a graduated arrangement under a
transparent glass lens and give off a yellow
light when switched on. They appear neutral in
colour when switched off.
LED technology offers numerous advantages:
– Rapid attainment of full power
– Up to 50 % energy saving as compared to
bulbs
– Service life equal to that of the vehicle
– Shallow design
– Bright, distinct marking effect makes
vehicle more noticeable
SSP282_088
Assistant lighting system
This system adapts the vehicle lighting to the
prevailing light conditions. For this purpose
the light switch must be set to AUTO. The rain
and light detector sensor G397 establishes
the prevailing light conditions and activates
the vehicle lighting system if appropriate.
Assistant lighting applies to:
– Dipped beam
– Parking lights
– Tail lights
– Number plate light
Operation of the assistant lighting system is
described in SSP 288 – Audi A8 ´03
Distributed Functions.
SSP282_110