2003 AUDI A8 sensor

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4-level air suspension
The introduction of the Audi A8 ´03 is
accompanied by a system featuring new
technical details and functions. The major
differences with respect to the familiar Audi
allroad quattro
® system are as follows:
EDC instead of PDC damping
The control system makes allowance for the
currently applicable driving status. Wheel
movement (unsprung masses) and body
movement (sprung masses) are detected.
Various damping characteristic curves are
implemented within the scope of three
selectable programs (modes) and each
damper can be controlled individually.
Control concept
Integration into the MMI makes for
convenient, logical and easy to remember
control action.
Extended range of sensors
Use is made of three acceleration sensors to
detect body movement.
External air springs
The air spring not only replaces the steel
spring, it also offers major advantages (refer
to SSP 242). The new external routing of the
air spring through an aluminium cylinder
permits the use of thinner-walled bellows.
This results in an even more sensitive
response to road surface irregularities.
SSP282_052
SSP282_053
Optimal comfort and road safety are thus
always guaranteed whichever mode is set
(comfort or sports).
The term "mode" thus describes a
coordinated combination of adaptive
suspension program and damping map.

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System layout
Running Gear
SSP282_054
Design and operation of 4-level air
suspension are described in SSP 292.
Front information and
display and operating
unit control unit J685
Front axle
level sensorsSolenoid valve blockRear axle
level sensorsPressure
accumulator
Adaptive suspension
control unitRear axle
air suspension struts Rear axle
acceleration sensors
CompressorControl unit with
display in dash panel
insert J285
Front axle
air suspension struts
Front axle acceleration sensors

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Driver convenience is further enhanced, as
fewer accelerator and brake pedal operations
are required. Speed restrictions and safety
factors are reliably observed and the flow of
traffic thus better regulated.
ACC (Adaptive Cruise
Control)
Adaptive Cruise Control is a new system
designed to assist drivers and offers a much
wider range of functions than the
conventional Tempomat.
Running Gear
If the distance is less than desired, the vehicle is
decelerated by reducing power, changing gear
and if necessary applying the brakes.
In the interests of comfort, maximum possible
braking is restricted to approx. 25 % of the
maximum deceleration potential of the brake
system (full braking).
The control action is designed to assist the
driver and thus contributes to greater road
safety.
In certain traffic situations, active braking by the
driver may still be necessary. Summary of Adaptive Cruise Control (ACC)
The basic Adaptive Cruise Control function is
to maintain a driver-selectable distance from
the vehicle in front. ACC thus represents the
logical next step on from the original cruise
control system.
The distance from and speed of the vehicle in
front are determined by a radar sensor. If the
distance is greater than desired, the vehicle is
accelerated until the required speed input by
the driver is achieved.
SSP282_057

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Radar sensor
An adapter plate permits fitting and
adjustment at a holder bolted to the centre of
the bumper bracket.
For details, refer to current Workshop Manual.
Design
Sender and control unit are integrated into
one housing - the distance regulation control
unit J428.
The entire assembly has to be replaced if the
control unit is defective. ACC system limits
– ACC is designed to assist the driver and
is not a safety system.
– ACC is not a fully autonomous driving
system.
– ACC provides control in a speed range of
30 - 200 km/h.
– ACC does not react to stationary objects.
– Radar operation is impaired by rain,
spray and slush.
– Tight bends may restrict operation on
account of the limited radar detection
range.
SSP282_058
Vertical
adjusting screwHolder
Distance regulation
control unit J428 with
radar sensor
Horizontal
adjusting screwMounting hole

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Electrical System
Convenience and security
electronics
"Advanced Key" entry and start
authorisation system
"Advanced Key" can be taken to mean an
"advanced locking and security system".
It takes the form of a non-contacting key
recognition system. With the "Advanced Key"
package, the "Vehicle unlocking" and "Vehicle
locking" functions by way of a mechanical or
remote control key are supplemented by the non-
contacting functions "Vehicle unlocking" and
"Vehicle locking".
Functions
Advanced Key "unlocking"
The key owner enters the key detection zone next
to the vehicle (less than 1.5 m from door handle)
and reaches into the recessed handle moulding.
aerial.
The key responds by way of radio waves and the
vehicle is unlocked if authorised.
Advanced Key "starting"
The driver presses the start button, which again
initiates a key scan via the passenger-
compartment aerials near the selector lever, at the
rear centre vents and at the rear centre armrest.
The remote control key provides confirmation,
with the result that the ignition is switched on on
depressing the first stage of the start button and
the engine started on depressing the second
stage. The engine is switched off with the STOP
button.
Advanced Key "locking"
If the vehicle is to be locked from the outside, it is
sufficient to press the locking button in one of the
door handles. Actuation of the locking button
triggers a key scan via the door handle aerial and
the vehicle is locked on confirmation of the remote
control key.In addition, the driver can start the engine
with the START/STOP button (START/STOP
function) without inserting the ignition key
in the electronic ignition lock.
SSP282_093
SSP282_094
SSP282_095
Design and operation are described in
SSP 287 – Audi A8 ´03 Electrical
Components.
A proximity sensor starts a key scan by way of an

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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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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

Downloaded from www.Manualslib.com manuals search engine Climatronic control unit J255
SSP282_100
Rear Climatronic control and display unit E265
Air conditioner basic setting
control
Heated rear window
control Front control panel
activation/
deactivation
Seat ventilation
control
Air distribution control
– Up
– Chest vent/centre
– Down Left rotary control/pushbutton
Rotary control +/- for
– Temperature
– Blower speed
– Air distribution up/down
– Seat heating
– Seat ventilation
– Menu control via MMI
Pushbutton
– Synchronisation of driver's
side, passenger's side and
rear settingsDriver's side
control panelPassenger's side
control panel Seat heating controlReset to basic setting/
automatic mode
Temperature sensor
with blowerAir conditioner defrost
and electrically heated
windscreen
Manual recirculated-air
mode control Blower control
Rear left
control panelCentre console/footwell
air distribution controlReset to basic setting/
automatic mode
Rear right
control panel
Left rotary control/pushbutton
Rotary control +/- for
– Temperature
– Chest vent and footwell air
distribution
– Seat heating
– Seat ventilation
Pushbutton
– Synchronisation of driver's
side and passenger's side
settings
Rear left seat heating
controlRear control panel
activation/
deactivation
Rear right seat
ventilation controlRear right seat heating
control
Rear left seat ventilation
control