2003 AUDI A8 wing

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Selector lever/button kinematics
To prevent inadvertent shifting into selector
lever position "S", a change has been made to
the selector lever kinematics such that
switching to "S" involves pressing the button
in the gearstick knob.
A small gear mechanism is provided in the
gearstick knob to reduce the required button
operating force.
The locking rod is actuated by the application
of pressure, which means changes have also
been made to kinematics and gearstick knob
assembly (refer to Workshop Manual).
In terms of the following functions, there are
interesting new aspects to the shift
mechanism in the new Audi A8 '03:
– Shift mechanism kinematics
– Ignition key removal lock
– Selector lever lock
– Selector lever lock emergency release
– Selector lever/lock button kinematics
Ignition key removal lock
Major modifications have been made to
operation of the ignition key removal lock and
selector lever lock (shiftlock). On account of
the new entry and start authorisation switch
E415, there is no mechanical link between the
shift mechanism and ignition lock (locking
cable).
Selector lever lock emergency release
This modification means that the selector lever
remains locked in position "P" in the event of
malfunctions or power supply failure
(e.g. battery flat).
Selector lever lock emergency release is
provided to enable the vehicle to be moved
(e.g. towed) in such situations.
Gearbox
SSP282_048 SSP282_049

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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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LOCAL INTERCONNECT NETWORK
Electrical System
The familiar CAN bus (two-wire bus) is
supplemented by the following bus systems:
– LIN bus (single-wire data bus)
– MOST bus (optical data bus)
– Bluetooth
TM (wireless data bus)
LIN bus
LIN stands for Local Interconnect Network.
Local Interconnect means that all control
units are located within a limited structural
space (e.g. roof). This is also referred to as
"local sub-system".
Data are exchanged between the individual
LIN bus systems in a vehicle by one control
unit in each case using the CAN data bus.
The LIN bus system is a single-wire data bus.
The wire has a basic colour (violet) and a code
colour.
The wire cross-section is 0.35 mm
2. A screen is
not necessary.
The system permits data exchange between
one LIN master control unit and up to 16 LIN
slave control units.
SSP282_031
Design and operation of the LIN bus
are described in SSP 286 – New data bus
systems.
Diagnostic connection Data bus diagnostic
interface (gateway)
LIN master
LIN slave 2 LIN slave 1
Diagnosis CAN

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Rear lights
SSP282_089
The newly designed rear lights are an ideal
combination of design, function and ultra-
modern technology.
Light-emitting diodes are used for the tail light,
brake light and turn signal indicator functions.
Newly developed "High-performance" bulbs
are employed for the lesser used rear fog light
and reversing light functions.
The high-level third brake light also features
LEDs.
Interior lighting
In addition to the usual interior, reading and
door lights, the new Audi A8 also features new
"ambiente" and door contour lights with
variable functions depending on the lighting
profile selected.
Users can choose between the following
lighting profiles:
– Highway
– City
– Cockpit
– Fond = Rear
Rear light actuation is described in
SSP 287 – Audi A8 ´03 Electrical
Components.
SSP282_111
Brake/tail light on
side panel
– Red LEDs
Turn signal
indicator
– Yellow LEDsBrake/tail light on
boot lid
– Red LEDs
Rear fog light
– 16 W HPV bulb
Reversing light
– 16 W HPV bulb
Reflector

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An optional feature for the Audi A8 ´03 is
4-zone climate control, enabling both driver
and all passengers to make individual
settings independently of the climate control
level selected for the other occupants.
Design and operation
The air conditioning system represents a
more advanced version of the concept
employed in the Audi A8 predecessor model
with 2-zone climate control and features fully
automatic regulation.
Heating/Air Conditioner
The following components are new features
as compared to the systems previously fitted
in the Audi A8:
– Humidity sender G355
– Evaporator outflow temperature sender
G263
– Two versions: 2-zone front climate control
with 12 control motors and 4-zone front
and rear climate control with 15 control
motors
– Rear climate control with electric rear
additional heater as additional equipment
("4-zone system") – rear left and rear right
footwell heater element Z42 and Z43
– Second control and display unit with
4-zone climate control, Climatronic control
unit J255, rear Climatronic control and
display unit E265– Climate control menu in MMI (Multimedia
Interface) for display of climate control set
values and basic settings
– Front and rear seat heating and seat
ventilation
– Heated windscreen Z2
– Energy management control unit J644
The interaction of these components in
coordination with the entire air conditioning
system forms a control loop and permits
comfortable front and rear climate control to
suit all requirements.
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A distinction is made between two air
conditioner unit versions
– 2-zone front and rear climate
control
– 4-zone front and rear climate
control
and three types of control and
display unit
– Air conditioner control panel with
no seat heating/ventilation
– Air conditioner control panel with
seat heating
– Air conditioner control panel with
seat heating and seat ventilation
(identified by part number index).
SSP282_099
Self-diagnosis
Fault diagnosis and measured value blocks
for air conditioner and seat heating system
can be read out by way of address words 08
"Air conditioner/heater electronics" and 28
"Rear climate control". The functions of and
exact procedure for self-diagnosis and
assisted fault-finding with VAS 5051 can be
found in the Heating/Air Conditioner
Workshop Manual for the relevant vehicle
model.
Operating principle
When the ignition is switched on, the
Climatronic control unit J255 starts up with
the same temperature, air distribution and
fresh-air blower speed settings etc. as were
applicable the last time the ignition was
switched off by way of the appropriate key or
using fingerprint recognition.
If fingerprint recognition has been
implemented, this has priority over key
recognition (refer also to SSP 287 – Audi A8 ´03
Electrical Components).
Personalised settings
The following settings can be made for each
climate control zone (front left, right and,
optionally, with 4-zone climate control rear left
and right):
– Left/right temperature
– Air flow
– Left/right air distribution
– Left/right seat heating
– Left/right seat ventilation
– Operating modes (AUTO for driver and front
passenger, temperature-adjustable centre
vents, automatically controlled
recirculated-air mode, ECON)
The heated windscreen can be activated by
way of the air conditioner defrost button or
the air conditioner control unit automatically
switches on the electric heated windscreen if
the appropriate conditions are satisfied
(windscreen defrost or automatic mode on
cold starting).
The Climatronic J255 and heated windscreen
J505 control units communicate by way of the
LIN bus. The Climatronic control unit transmits
the specified windscreen heating power to the
heated windscreen control unit on the LIN bus.
Heating/Air Conditioner
Key recognition takes place in the case of
remote control (radio or key transponder),
with the driver identification control unit
providing the Climatronic control unit J255
with the appropriate information by way of
the CAN bus.
The electrically heated windscreen is only
supplied with the amount of power which can
currently be drawn from the electrical system
without draining the battery. This is
monitored by the energy management
control unit J644.
As is the case with the Audi A4, the
windscreen is heated by applying voltage to a
metallic foil fitted in the glass (refer to
SSP 213).
As in the Audi A4, the air conditioner
compressor is regulated as a function of load
and controlled externally by way of the
compressor regulating valve (refer to
SSP 240). The Climatronic control unit J255 is
connected to the convenience CAN, via
which diagnosis is also performed.
A manual air conditioning system is not
available.

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3
36
Auto
21,5° C
63
3
The current air conditioner settings are stored
automatically and assigned to the
appropriate remote control key. On vehicles
with Audi one-touch memory (optional), the
current setting is also assigned to the
corresponding fingerprint. Air conditioning system control via MMI
All air conditioning system set values and
basic settings (setup) can be displayed by
way of the MMI. This applies both to the
Climatronic control unit button functions and
to setup.
If the air conditioning system is activated
with the MMI switched on, the air conditioner
function settings can be called up and altered
by way of the multimedia control panel. The
functions indicated in the corners of the
displayed mask are activated using the
softkeys.
Basic setting (setup)
The basic air conditioner settings can only be
altered when the MMI is active. This involves
pressing the SETUP button on the Climatronic
control unit.
The following functions can be selected:
– ECON ON/OFF
– Automatic air recirculation active/inactive
– Synchronisation active/inactive
– Centre vent (temperature-adjustable)
settings between - 3 and + 3
– Auxiliary heater active/inactive
– Auxiliary ventilation active/inactive
– Auxiliary heater/ventilation operating time
15 min./30 min./45 min./60 min.
– Auxiliary heater/ventilation timer status for
timers T1, T2, T3 ON/OFF
– Solar mode active/inactive (solar cells
C20)
– Rear control ON/OFF
The desired settings can be called up and
altered with the driver's/front passenger's
control knob on the Climatronic control unit.
SSP282_112
SSP282_113
low high
Econ
Distribution Seat ventilation
Blower Seat heatingAC - driver
Blower Seat heatingAC setup
Distribution Seat ventilation
Off
Autom. air recirculationOff
Synchron.Off
Centre vent

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Electric rear additional heater
An electric rear additional heater is fitted
under each front seat in the rear climate
control footwell air ducts.
Heating/Air Conditioner
A further advantage is that independent
temperature regulation (heating) can be
provided for the rear footwell with the 4-zone
system.
A supply of colder air to the rear climate zones
as opposed to the front can be achieved by
way of the centre chest vents.
The temperature can however only be reduced
but not increased via these vents through the
addition of cold air.
As in the predecessor model, two separately
controlled heat exchangers permit the setting
of different temperatures at front left/right.
All occupants can therefore be provided with
individual climate control. Operation
Following a cold start or at low ambient
temperatures, there is insufficient waste heat
in the coolant to warm the rear of the vehicle
by means of a conventional fluid-filled heater.
In addition, the drop in temperature in the rear
air duct is extremely high in the initial phase.
This problem has been solved by integrating
two electric rear additional heaters into the
rear footwell air duct.
These employ electrical energy from the
vehicle electrical system to heat the air
supplied to the passenger compartment.
In this way, the heating function is available
immediately following cold starting.
As was the case with the predecessor
model, in situ heat exchanger
replacement is possible. The procedure
involved is described in the current
Workshop Manual.
SSP282_102