warning AUDI A4 2001 B5 / 1.G Technical Features Design And Function

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13
The system comprises driver/passenger air-
bags, front side airbags, optional rear side
airbags, SIDEGUARDS
®

, three point front seat
belts with ball tensioners and belt force limit-
ers, three point rear outer seat belts, centre
lap belt (for fixed rear seat bench), Isofix pre-
paration in rear of vehicle, and a total of 6
non-central accelerometers:
– 2 front impact crash sensors
– 2 driver/passenger side airbag crash sen-
sors, (in the B-pillar for side impact)
– 2 driver/passenger rear side airbag crash
sensors, (on the C-pillar for side impact) To complement the comprehensive body
modifications, occupant protection has been
improved through the further development of
the familiar 8.4 airbag system.
The new generation bears the designa-
tion 8.4 E, where the E stands for
"extended".
The position of the sensors is selected so that
they are installed as near as possible to the
outer structure of the vehicle.
This enables quicker deceleration detection in
the event of an impact.The external sensors deliver digitised acceler-
ation data to the airbag control unit, which is
then evaluated in the control unit and which
triggers the relevant restraint system compo-
nents.
Key
E224 Key switch for switching off
passenger’s side airbag
G179 Side airbag crash sensor, driver’s
side (B-pillar)
G180 Side airbag crash sensor, passenger’s
side (B-pillar)
G256 Crash sensor for rear side airbag,
driver’s side
G257 Crash sensor for rear side airbag,
passenger's side
G283 Front airbag crash sensor, driver’s
side
G284 Front airbag crash sensor,
passenger’s side
J162 Heater control unit
J220 Control unit for motronic
J234 Airbag control unit
J285 Control unit with display unit in
dash panel insert
J393 Central control unit for convenience
system
J526 Control unit for telephone /
telematics
J533 Diagnosis interface for data bus
(Gateway)K75 Airbag warning lamp
K145 "Airbag off" warning lamp,
passenger's side
N95 Airbag igniter, driver's side
N131 Airbag igniter 1, passenger's side
N153 Igniter for belt tensioner, driver's side
N154 Igniter for belt tensioner,
passenger's side
N199 Igniter for side airbag, driver’s side
N200 Igniter for side airbag, passenger's
side
N201 Igniter for rear side airbag,
driver’s side
N202 Igniter for rear side airbag,
passenger's side
N277 Igniter for airbag in B-pillar
(SIDEGUARD

®

), driver's side
N278 Igniter for airbag in B-pillar
(SIDEGUARD
®

), passenger's side
T16 Connector, 16-pin, diagnosis
connection

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Re-encoding of the airbag control unit is no
longer possible after the first crash data mes-
sage is stored.
Triggering is performed in two thresholds
depending upon the deceleration value:
– Threshold 1 = belt tensioners only
– Threshold 2 = belt tensioners and airbag(s)
Crash sensors for side airbags
G179, 180, 256, 257
In order to trigger the components of the
restraint system, two simultaneous impact
detection signals are required for the plausi-
bility check:
– from both opposing crash sensors
(B-pillar left with right and/or
(C-pillar left with right) and
– from the control unit internal crash sen-
sors.
The crash sensors are designed in such a way
that incorrect installation is excluded.
Airbag control unit J234
The warning lamp for airbag K75 is activated
continuously following a detected impact.
"CRASH DATA STORED" and the triggered
components are displayed with fault code
during fault memory readout.
Sensors and components to be replaced
following an accident, are listed in the
current workshop manual.
SSP254_059

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Crash signal processing
There are two separate crash signal outputs:
One crash signal is output via the conven-
tional wiring and triggers the following func-
tions:
– Transmitting an emergency call via the
control unit for telephone/telematics J526
(optional)
– unlocking the vehicle,
– Switch on interior light
(switch must be set to door contact),
– switching on hazard warning lights via the
central convenience electronics J393.
The auxiliary heater J162 (optional) is
switched off by the central convenience
electronics J393 via a CAN convenience
message.
The second crash signal output functions via
the convenience CAN bus, which switches off
the engine fuel supply via the engine control
unit J220.

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Electrical system
Steering column switch
module
Due to the compact design of the newly
developed steering column switch module, it
was possible to minimise the amount of wir-
ing necessary and the space requirements.
A self-diagnosis facility for the steering col-
umn switch is now available with new switch
module.
The steering column switch module consists
of the following components:
– Turn signal switch
– Wiper switch with interval potentiometer
– Separate steering column switch cruise
control system operation
– Coil spring for diver's airbag
– Steering angle sensor for ESP
– Steering column electronics for signal con-
version and processing of drive and con-
venience CAN BUS J527
In addition, the steering column electronics
register the ignition switch signals.
Furthermore, the control buttons for multi-
function and "tiptronic" steering wheel are
registered via the steering wheel electronics
module.
Steering column switch
Detection of the respective switch positions is
effected via voltage coding, using various
resistance values in the relevant position. The
steering column electronics evaluates this
switch information and transmits it, via the
convenience CAN BUS, to the vehicle electri-
cal system control unit J519.
Cruise control system (CCS)
For ergonomic reasons, the control switch for
the cruise control system is located on the
left side of the steering column, below the
turn signal lever.
Warning lamp K31 in the dash panel insert
illuminates when the CCS is in control mode.
The modified operation of the CCS Steering
column switch function is described in the
Owner's Manual.
Cruise control
system E45
Ignition
steering lock Steering column
electronics J527
Turn signal
switch E2
SSP254_105

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The control unit for vehicle electrical system
J519 is the newly developed electronic central
electrics and comprises a comprehensive
self-diagnosis, which can be selected directly
with address word 09.
The control unit for vehicle electrical system
receives the input signals from the conven-
ience CAN BUS via the steering column
switch module or the rotary light control.
Pb1J0 915 105 A 1J0 915 105 A
C C
The power connections for the individual con-
sumers are driven via semi-conductor ele-
ments, e.g. transistors.
A separate supply is not required, as this is
provided by the internal electronics in the
event of a fault.

J4
Dual tone-
horn H2/H4 Control unit for
speech entry J507
Power supply
Hazard warning lights switch E3
Steering col-
umn electron-
ics J527 Rotary light control E1
Wiper system
Lighting system
Dash panel insert J285Control unit for trailer
recognition J345 Control unit for
vehicle electri-
cal system J519
Relay for
X contact J18

Electrical system
Control unit for vehicle
electrical system J519
SSP254_068

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49
There are three control unit versions:
– "lowline" for the standard version
– "lowline" for vehicles with headlight
washer system
– "highline" for vehicles with driver informa-
tion system
The following functions are available with the
"lowline" version:
– Wash/wipe control and interval
– Hazard warning and turn signal control
– Actuation of horn and load-reduction relay
– Parking light left/right
– Side light left/right
– Main beam left/right and headlight flasher
– Number plate lightThe "highline" version implements the driver
information system function and also
performs the following control functions:
– Driving light and dipped beam left/right,
– Fog lights and rear lights,
– Reversing lights,
– Brake lights
with separate outputs to each of the individ-
ual consumers.
Light control
In the highline version, light control is trans-
mitted from the steering column switch
module or directly from the rotary light
control, via the convenience data bus, to the
vehicle electrical system control unit.
Parking lights
Main beam
Headlight flasher Side lights
Dipped beam
*

Fog lights
*

Rear fog lights
*

*

In the "lowline" version, the components marked with
an asterisk are connected via conventional wiring and
fuses, directly to the lighting units.
Control unit for
vehicle electrical
system J519

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Auxiliary signals
1 CAN high convenience
2 CAN low convenience
3 Terminal 75
4 not fitted with trailer coupling
5 only with trailer coupling
6 Automatic gearbox "multitronic"
7 Manual gearbox
A
U
X
Y
Z
Electrical system
"lowline" version
Components
E1 Light switch
E3 Hazard warning light switch
F Brake light switch
F4 Reversing light switch
F216 Contact switch for switchable
rear fog lights
H2 Treble horn
H7 Bass horn
J4 Relay for dual tone horn
J59 Load-reduction relay for x contact
J345 Control unit for trailer recognition
J446 Control unit for parking aid
J519 Control unit for vehicle electrical
system
L22 Bulb for fog light, left
L23 Bulb for fog light, right
L46 Bulb for rear fog light, left
L47 Bulb for rear fog light, right
M1 Bulb for side light, left
M2 Bulb for rear light, right
M3 Bulb for side light, right
M4 Bulb for rear light, left
M5 Bulb for turn signal light, front left
M6 Bulb for turn signal light, rear left
M7 Bulb for turn signal light, front right
M8 Bulb for turn signal light, rear right
M9 Bulb for brake light, left
M10 Bulb for brake light, right
M16 Bulb for reversing light, left
M17 Bulb for reversing light, right
M18 Bulb for side turn signal light, left
M19 Bulb for side turn signal light, right
M25 Bulb for high-level brake light
M29 Bulb for dipped beam headlight, left
M30 Bulb for main beam headlight, left
M31 Bulb for dipped beam headlight, right
M32 Bulb for main beam headlight, right
S Fuses
U10 Socket for trailer operation
V Windscreen wiper motor
V5 Windscreen washer pump
Colour coding
= Input signal
= Output signal
= Positive power supply
= Earth
= CAN-BUS
V11 Pump for headlight washer
conditioning system
V48 Servo motor for headlight range
control, left
V49 Servo motor for headlight range
control, right
X Number plate lights
Connection within the
functional diagram

Functional diagram
Control unit for vehicle
electrical system J519
{

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Auxiliary signals
1 CAN high convenience
2 CAN low convenience
3 Terminal 75
4 Terminal 31
U Connection within the functional
diagram V11 Pump for headlight washer
conditioning system
V48 Servo motor for headlight range
control, left
V49 Servo motor for headlight range
control, right
X Number plate light
"highline" version
Components
E1 Light switch
E3 Hazard warning light switch
F Brake light switch
F216 Contact switch for switchable
rear fog lights
H2 Treble horn
H7 Bass horn
J4 Relay for dual tone horn
J59 Load-reduction relay for x contact
J345 Control unit for trailer recognition
J446 Control unit for parking aid
J519 Control unit for vehicle electrical
system
L22 Bulb for fog light, left
L23 Bulb for fog light, right
L46 Bulb for rear fog light, left
L47 Bulb for rear fog light, right
M1 Bulb for side light, left
M2 Bulb for rear light, right
M3 Bulb for side light, right
M4 Bulb for rear light, left
M5 Bulb for turn signal light, front left
M6 Bulb for turn signal light, rear left
M7 Bulb for turn signal light, front right
M8 Bulb for turn signal light, rear right
M9 Bulb for brake light, left
M10 Bulb for brake light, right
M16 Bulb for reversing light, left
M17 Bulb for reversing light, right
M18 Bulb for side turn signal light, left
M19 Bulb for side turn signal light, right
M25 Bulb for high-level brake light
M29 Bulb for dipped beam headlight, left
M30 Bulb for main beam headlight, left
M31 Bulb for dipped beam headlight, right
M32 Bulb for main beam headlight, right
S Fuses
U10 Socket for trailer operation
V Windscreen wiper motor
V5 Windscreen washer pump
Electrical system
Colour coding
= Input signal
= Output signal
= Positive power supply
= Earth
= CAN-BUS
Functional diagram
Control unit for vehicle
electrical system J519

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The hazard warning flasher signal is control-
led separately by the vehicle electrical system
control unit, via the hazard warning flasher
button.
If, during hazard warning flashing, the turn
signal flasher is actuated, e.g. during towing,
the hazard warning lights lose their priority
for this period.
The turn signal clicking is generated by an
integral acoustic relay in the dash panel
insert.
Turn signal/hazard warning light control
The functions:
– Anti-theft alarm flasher
– Central locking system flasher when
opening/closing
– Key-learn flasher for key adaption
– Crash flasher
– Panic flasher (USA only)
are specified by the central convenience elec-
tronics and transmitted via the convenience
data bus to the vehicle electrical system con-
trol unit, which then executes the "com-
mands".
The signal for turn signal flashing or motor-
way flashing is output via the steering column
switch module and executed by the vehicle
electrical system control unit.
For active hazard warning flasher with
ignition OFF, the flasher bulbs are actu-
ated for a shorter period in order to mini-
mise current consumption.
Motorway flashing is detected by the vehicle
electrical system control unit when the turn
signal lever is pressed and this triggers a tri-
ple turn signal flash.

Turn signal light, right
Turn signal light, left
Turn signal light, right
Turn signal light, left
SSP254_077
SSP254_078

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Control unit for trailer recognition J345
A separate control unit is required for trailer
operation. This transmits the vehicle lighting
system convenience CAN messages from the
vehicle electrical system control unit to the
trailer lights. A parallel link from the trailer
socket to the vehicle wiring would result in
fault detection via the microprocessor in the
vehicle electrical system control unit.
The diagnostic function of the control unit for
trailer recognition is performed via the
vehicle electrical system control unit J519,
address word 09.
In the case of faulty communication
between the control unit for trailer recog-
nition and the vehicle electrical system
control unit, the rear lights are actuated
as a warning signal.
RT

Address word 09 - vehicle electrical system/
Central convenience
electronics
Communication takes place by means of the
convenience data bus via the central conven-
ience electronics, as no separate K-wire
leads to the vehicle electrical system control
unit. For this reason, intact central conven-
ience electronics are essential for perform-
ing self-diagnosis.
K wireCAN
BUS
Central convenience
electronics J393
SSP254_018J389
J388J387
J386
Door control units
Control unit for vehicle
electrical system J519
Control unit for trailer
recognition J345
09 – Electronic central electrics
8E0907279B
int. load module RDW 0811
Code 101
Dealership No. 6803
02 - Interrogate fault memory
03 - Final control diagnosis
04 - Basic setting
05 - Erase fault memory
06 - End output
07 - Encoding control unit
08 - Read measured value block
09 - Read individual measured value
10 - Adaption
11 - Log-in procedure

Measuring
equipmentSkip PrintHelp
Steering column
switch module J527
Vehicle self-diagnosis

Steering wheel
electronics
module J453
SSP254_016
VAS 5051