warning AUDI A6 ALLROAD 1999 C5 / 2.G Pneumatic Suspension System

3
Contents
System description . . . . . . . . . . . . . . . . . . . . 4
The self-study programme is not intended as a workshop manual.
The self-study programme will provide you with information on
the design and functions of the different assemblies/systems.
New
NoteImportant:
Note
Page
For maintenance and repairs please refer to the current technical
literature.
Operation and display
Operation ................................................................................. 7
Display ..................................................................................... 8
Self-levelling suspension control unit J197 ....................... 34
Modes .................................................................................... 35
Control concepts
Service
Special tools .......................................................................... 38
Basic system settings .......................................................... 39
Self-diagnosis ....................................................................... 40
General overview .................................................................. 41
Control strategies
System components
Air springs .............................................................................. 14
Air suspension ...................................................................... 17
Diagram of pneumatic system ............................................. 20
Solenoid valves ...................................................................... 21
Temperature sensor G290..................................................... 22
Pressure sensor G291............................................................ 22
Level senders G76, G77, G78, G289 ..................................... 23
Warning lamp K134 ............................................................... 27
Operating unit E281 .............................................................. 28
CAN information exchange ................................................. 29
Additional interfaces ............................................................. 30
Function diagram ................................................................... 32
Interfaces
Control strategies, control unit 4Z7 907 553A ................... 10
Control strategies, control unit 4Z7 907 553B ................... 12
ESP safety switching ............................................................ 13
Order No.:

507.5320.01.00
This figure can be ordered as a size A0 poster through
Bertelsmann Distribution for a net price of DM
15.00 DM/7.50 EUR
.
Direct ordering through Bertelsmann only applies to Germany.
Dealers in export markets are requested to contact their importer.

9
243_022
243_023
243_024
243_025
Other button functions
Automatic switching
The so-called “manual mode” can be
switched on or off by pressing the “raise” or
“lower” button for at least 3 sec. The yellow
LED marked “man” indicates to the driver that
the vehicle is in manual mode.
The automatic “parking level control” and
“motorway mode” functions are deactivated
in manual mode.
Switching off control system
The control system is switched on or off by
pressing both level buttons for longer than
5 seconds.
When the control system is switched off, the
LEDs in the operating unit for manual mode,
both level buttons and the warning lamp K134
are illuminated.
The level-indicating LEDs show the level set.
The corresponding LED is continuously
illuminated.
A control system that has been switched off
will be automatically switched back on again
when the driving speed exceeds approx.
10 km/h (unless the lifting platform mode is
recognised).
The control system can also be switched off
using the diagnostic testers (see Workshop
Manual).
It is often advisable to switch off the
system during repair work (e.g. during
axle measurement or if the pressure
lines have been detached) in order to
prevent the compressor from running
unnecessarily.
Display example: Manual mode and NL
Display example: Raising from LL to HL1
Display example: Raising from HL1 to HL2
Display example: Lowering from NL to LL

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If, for example, the vehicle is at high level 2
with active ESP influences and the driver
accelerates sharply on a very winding route,
speeds of > 35 km can be achieved in high
level 2. In order to guarantee maximum safety
in such driving conditions, ESP influences are
automatically deactivated at a speed of
> 70 km/h, despite the high centre of gravity
of the vehicle (ESP-safety switching).
Normal ESP functions are available again and
the ESP warning lamp extinguishes.
This ESP safety switching takes place as of
70 km/h at high level 2 and as of 120 km/h at
high level 1.
There is no ESP safety switching at normal
level or low level.
ESP safety switching
For technical reasons it is not possible to
change levels/self-level during cornering. If
cornering is recognised, no control functions
are performed and control functions already
running are interrupted. The target level
remains stored and is reset when straight-
ahead driving is recognised.
In the Audi allroad quattro it is possible to
influence certain ESP functions using the ESP
button.
You can find further information about this in
SSP 241, from page 67 onwards.
If ESP influences have been activated (via ESP
button, ESP warning lamp illuminated), the
transverse dynamics control (anti skid
function) is passive (not during braking).
0 35 80 12070

ESP switching at high level 2
No self-levelling while
corneringESP switching at high level 1
Speed km/h No self-levelling while
cornering
243_027
Cornering is detected by the J197 self-
levelling control unit by evaluation of
the signals from the four level sensors.
LL NL HL1HL2

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System components
243_006
243_007
WrongCorrect
Air springs must not be moved when
pressureless because the air bellows
cannot unroll on the piston and would
be damaged.
In a vehicle with depressurised air
springs, the relevant air springs must
be filled with the aid of the diagnostic
tester (see Workshop Manual) before
raising or lowering the vehicle (e.g. on a
vehicle lifting platform or vehicle jack).
Warning:
The piston must not be touched during
installation or transport of the
complete suspension strut assembly as
the piston can be easily pushed back
when unpressurised.
If the sealing ring is pushed out of
position (by the air spring pressure) the
air spring will not be sealed correctly.

27
Warning lamp K134...
... illuminates for one second when
terminal 15 is ON (self-test).
... is constantly illuminated in the
case of relevant system errors or
when the system is switched off.
... is constantly illuminated during
basic system setting and when
basic system setting has not been
performed successfully.
... flashes in the case of extremely
low or high levels.
... flashes during final control
diagnosis.
242_050 Warning lamp K134
As no magnetic materials are required,
temperature and age cause only minimal
variances in the measured values. Such
variances are caused by a reduction in the
strength of the magnetic field of permanent
magnets over time or due to temperature
changes. Level sensors, summary
The advantages of the angle sensor are the
proportional measurement process along
with their contact-free and therefore wear-
free operation.
The generation of ratios (proportional
measurement) means that the output signal
proportional to the angle is largely
independent of mechanical tolerances such
as distance changes, axle movement or
inclination errors. Magnetic interference is
also largely suppressed due to the generation
of ratios.

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CAN information exchange
In the case 4-level air suspension, the
information exchange between control unit
J197 for the self-levelling system and the
networked control units is performed via the
CAN drive with the exception of a few
interfaces.
Interfaces
The system overview shows the information
provided by the gearbox control unit via the
CAN bus which is received and used by the
networked control units.
Information sent by the J197
control unit.Information received and
evaluated by the J197 control
unit.
Engine control unit:
Engine speed
Self-levelling suspension control
unit J197
System status (OK or not OK)
Warning lamp (on/off)
Self-diagnosis
Fault memory entry
Type of vehicle (e.g. allroad
quattro):
Level status
Intermediate level
Parking level
Impending adjustment
Adjustment active
Raising level
Lowering level
Switching to FR
Switching to FL
Switching to RR
Switching to RL
ESP influence CAN drive high
CAN drive low
ESP control unit:
Driving speed
ESP status
For detailed information on the CAN
bus, please refer to SSPs 186 and 213.

33
Key to function diagram
E281 Self-levelling suspension operating
unit
F216 Contact switch for switchable rear fog
light
G76 Self levelling suspension sender, RL
G77 Self levelling suspension sender, RR
G78 Self levelling sender, FL
G289 Self levelling suspension sender, FR
G290 Compressor temperature, self-
levelling suspension sender
G291 Self-levelling suspension pressure
sender
J197 Self-levelling suspension control unit
J403 Relay for self-levelling suspension
compressor
J429 Control unit for central locking
J431 Control unit for headlamp range
control
N111 Discharge valve for self-levelling
suspension
N148 Valve for FL suspension strut
N149 Valve for FR suspension strut
N150 Valve for RL suspension strut
N151 Valve for RR suspension strut
N311 Valve for self-levelling suspension
pressure accumulator
K134 Self-levelling suspension warning
lamp
V48 Left headlamp range control motor
V49 Right headlamp range control motor
V66 Self-levelling suspension compressor
motor= Input signal
= Output signal
= Positive
= Earth
= Bi-directional
= CAN bus/signal wire
Auxiliary signals:
CAN low
CAN high
Door contact signal
Diagnostic connector for K wire
Vehicle locked signal
Trailer operation signal (F126)
Terminal 50 signal
Driving speed signal
Terminal 56
Diagnostic connector for K wire
to the instrument cluster
Driving speed signal from ABS control unit,
speed sensor output, rear left
1
2
3
4
5
6
7
8
I
II
III
IV
Terminal 58s
Terminal 58d
ESP button
ESP button
A
B
C
DHeadlamp range control signal
9
Power supply J431
10

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Allroad quattro control strategies
4-level air suspension + additional shift stage
0203580 60
5100 120 130 200
30
General overview
Control unit 4Z7 907 553A/B
ESP safety-switching
Automatic lowering
Parking level
control
v >70 km/h: Engine intervention
v >50 km/h: Acoustic and visual warning in low range
Air supply: control primarily via
pressure accumulator <36 km/hVehicle speed v
in km/h
v <30 km/h: shift to low range possible
Additional shift stage
Air supply: control primarily via compressor >36 km/h
Pressure accumulator filled >36 km/h
Motorway mode:Lowering: >120 km/h >30 seconds
Raising: <70 km/h >120 seconds
<35 km/h >30 seconds
<5 km/h immediately
Manual mode:- no parking level control
- no motorway mode
- automatic lowering from HL2
and HL1; ESP safety-
switching remains active
Automatic mode:- parking level control (HL1)
- motorway mode:
- automatic lowering from HL2 and HL1.
- ESP safety-switching
LL NL HL1 HL2243_040
Control unit 4Z7 907 553B: Automatic mode:- no parking level control
- automatic raising to HL1
<60 km/h >30 seconds
<30 km/h immediately