AUDI A8 2003 D3 / 2.G Technical Features Manual

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For internal use only All rights reserved. Subject to
technical modification.
Copyright* 2002 AUDI AG, Ingolstadt
Department I/VK-35
D-85045 Ingolstadt
Fax 0841/89-36367
000.2811.02.20
Technical status as at 09/02
Printed in Germany
AUDI A8 ´03 - Technical Features
Self Study Programme 282
282
282

Downloaded from www.Manualslib.com manuals search engine 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, Bluetooth
TM
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

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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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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 functionActive head restraints
for front seats

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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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9712944
5051
1136
714 125
Brief outline
Body
SSP282_026
Kerb weight 1,780 kgGross weight 2,380 kg
Turning circle 12 mLuggage compartment volume approx. 500 l
Tank capacity approx. 90 litresDrag coefficient 0.27 Cd
1629
1894
1444
2028
1615
976

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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

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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

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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.
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

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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 aidCatch Bowden
cable