Audi 2003 A8 Owner's manual

Service.
For internal use only
All rights reserved. Subject to
technical modification.
Copyright* 2002 AUDI AG, Ingolstadt
Department I/VK-35
D-85045 Ingolstadt
Fax [phone]
000.2811.02.20
Technical status as at 09/02
Printed in Germany
AUDI A8 ´03 - Technical Features
Self Study Programme 282
282
282

Complete vehicle information
The design and operation of the Audi A8 ´03 are described in the following Self Study
Programmes:
Other helpful information on the
Audi A8 ´03 can be found on the adjacent
CD ROMs.
Electrical system CAN data bus 2
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, BluetoothTM
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

3
Attention
Note
New
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.

4
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.
Introduction
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.
Convenience/infotainment control
via multimedia interface (MMI)
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
Active head restraints
for front seats

5
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

6
971 2944
5051
1136
714
125
Brief outline
Body
SSP282_026
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 Cd
1629
1894
1444
2028
1615
976

7
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.
SSP282_027
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.
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

8
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.
SSP282_029
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.
Body
SSP282_030

9
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.
SSP282_032
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.
SSP282_033
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.
Large upper castings
Extruded sections
Large lower castings

10
Body
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.
SSP282_035
The drive unit is only encased in foam and
inserted between side panel and battery.
Boot lid
Electronic boot lid lock
with microswitch
Foam encasing
Motor for automatic
closing aid
CatchBowden
cable

11
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.
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.
SSP282_036
Automatic boot lid
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.
Hinge mechanism
(open)
Boot lid
control unit J605
Button in driver's door Button on boot lid Vehicle key

12
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.
Rear doors
Large, high-strength side impact members
are integrated into the door to provide even
load distribution in the event of side impact.
SSP282_039
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.

13
Seats
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
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.
SSP282_116
Crash-active, electronic
head restraint with 70 mm height
adjustment
Thorax/pelvis
side airbag
Backrest fan
Seat cushion 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.
Backrest adjustment –
The angle of the top 1/3of the
backrest can be adjusted by 15°
for enhanced shoulder comfort.
Lumbar support with massage
function over a length of 60 mm

14
G 256
N251
G179 G180
N153
K145
AIRBAG
OFF
N95/G85
N202
N154
N252
G 257
J533
N199
N201
G 283 G 284
N131
N200
T16
J623
J285/K75 E224
AUS EIN
AIRBAG
J655
E24 E25
J234
N196 N198 N197
J393
J526
System layout
Passenger Protection
SSP282_068

15
The wide range of sensors permits detection
not only of head-on collision and side impact,
but also of rear-end collisions.
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 two-
stage front airbag triggering, active front head
restraints and a battery cut-off element.
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)
Key
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

16
15
J234
J655
1
2
E224
3
G283 G284 G179
N131
F138
N202N199 N200 N201
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
Block diagram
Passenger Protection
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

17
4 5 6 7
G256 G257 E24 E25
N198N251 N252 N153 N154 N196 N197
G180
N251 Curtain airbag igniter, driver side
N252 Curtain airbag igniter,
front passenger side
Colour code
= Input signal
= Output signal
= Positive supply
= Earth
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
1
2
3
4
5
6
7
SSP282_069

18
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
Passenger Protection
SSP282_070
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 non-
moving centre section of the steering wheel.
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.

19
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)
SSP282_081
SSP282_114
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.
In this way, severe impact in the knee zone is
avoided.
Knee airbags are required by legislation in the
USA.

20
Passenger Protection
Up-front sensors
For the first time, use is made in the
Audi A8 ´03 of so-called up-front sensors.
SSP282_072
Lateral acceleration sensors
Further acceleration sensors are
located at the B and C-pillars.
SSP282_073
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.
These take the form of two additional front-
end acceleration sensors on the right and left
beneath the corresponding headlight.
C-pillar sensor B-pillar sensor