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

Service.For internal use only All rights reserved, including
the right to make technical
changes.
AUDI AG
Dept. I/VK-5
D-85045 Ingolstadt
Fax 0841/89-36367
040.2810.62.20
Technical status 11/00
Printed in Germany
Pneumatic suspension system Part 2
4-level air suspension
in the Audi allroad quattroDesign and function
Self-study programme 243
243
243

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.

34
However, all level sensors (left and right) are
required in the air suspension system run-up
and run-on mode (ignition OFF).
To allow the left-hand level sensors to deliver
measured values in the case of the 4-level air
suspension in the allroad quattro, power is
supplied to control unit J431 (HRC) from
control unit J197).
This ensures that voltage is supplied to all
level sensors when control unit J197 is active.
Self-levelling suspension
control unit J197
The central element of the system is the
control unit which, in addition to its control
functions, enables the monitoring and
diagnosis of the entire system.
The control unit detects the signal from the
level sensors and uses it to determine the
current vehicle level. This is compared with
the reference level and corrected if necessary,
depending upon further input variables
(interfaces) and its internal control
parameters (reaction times and level
deviations).
It differentiates between various control
situations and controls them via the relevant
control concepts (see Control concept).
Comprehensive self-diagnosis facilitates
inspection and service of the system (see
Workshop Manual).
There are two control units currently in use,
depending on the country.
Control units with the part numbers
4Z7 907 553A and 4Z7 907 553B have different
control strategies (see page 10 onwards).
A common control strategy for all countries
(as for Index “B”) is planned for the future.
Control concepts
243_039
The system can be tested via the self-
diagnosis or test adapter 1598/35.
For further information, see “Service”
chapter.
Address word 34
Power supply to the headlamp range control
system
As previously described in the “Level sensors”
section, voltage is supplied to the left-hand
level sensors by the headlamp range control
unit J431)
Headlamp range control requires neither run-
up nor run-on times, so the voltage is
normally supplied to control unit J431 via
terminal 15 (ignition ON) (see function
diagram, page 32).

38
Special tools
Adapter cable 1598/35 with test box 1598/14
are used for fault finding and function testing
of sensors and signals of the 4-level air
suspension system.
As the pin assignment of the test box is not
compatible with the pin assignment of
control unit J197, pin template
V.A.G 1598/35-1 must be used.
Pin assignment is only possible by means of
pin template V.A.G 1598/35-1.
Service
Due to the limited number of
connections to test box V.A.G. 1598/14,
not all interfaces in control unit J197
are wired.
243_016
243_017
Adapter cable 1V.A.G 598/35
Pin template V.A.G. 1598/35-1
Test box
V.A.G. 1598/14

40
Self-diagnosis
Address word: 34 Self levelling suspension
Both generations of diagnostic tester
(V.A.G. 1551/1552 and VAS 5051) are suitable
for communication with the 4-level air
suspension control unit.
Due to the limited capacity of the tester
program cards, there are display text
limitations in the case of diagnostic testers
V.A.G. 1551 and 1552 (see. e.g. Workshop
Manual, Self-diagnosis function 03, Final
control diagnosis).
Service
198_039

Service.For internal use only All rights reserved, including
the right to make technical
changes.
AUDI AG
Dept. I/VK-5
D-85045 Ingolstadt
Fax 0841/89-36367
040.2810.62.20
Technical status 11/00
Printed in Germany
Pneumatic suspension system Part 2
4-level air suspension
in the Audi allroad quattroDesign and function
Self-study programme 243
243
243