mikef

2001 Allroad with 70K miles.

Yesterday, the yellow vehicle up/down icon light came on on the instrument cluster. This is the one that comes on if you mess up doing the 402 mod. Self levelling test triggers it, also.

My suspension would still raise and lower to all levels, and the Xenon headlight positioning was fine.

Here is what the VAG-COM tool said:

2 Faults Found:

00774 - Level Control System Sensor: Left Rear (G76)
57-00 - Electric Circuit Failure
01771 - Contol Module for Headlight Range (J431)
79-00 - Please Check Fault Code

I insepected the level control sensor on the left rear control arm. There did not seem to be any loose connections - the 4 wires into the connector do not have any visible corrosion.

I tried to clear the fault code yesterday, but they kept coming right back. Today, the instrument vehicle up/down icon/light was off. Also I was able to clear the fault code with the VAG tool, inside the level control module. It has not come back

I called my trusted Audi mechanic, he hadn't heard of this issue. Has anyone heard of this, and/or does anyone have any ideas what might have caused this, what to beware of, etc.

Thanks

Mike

Rally_nutcase_1982

Every Level sensor is very much a resistor that changes throughput with every movement.

Here is what you could do to be sure: use the VAG and address the sensor (like 402 mod cycle), losen the sensor so you can move the arm and change the setting (VAG) by only 1mm - see if the VAG gives you a valid or invalid reading.

If an invalid comes back then you will not be able to apply channel 5 (final setting written to module) but that's no big deal. Your current settings will still apply and you should be able to drive normal and change the ride height.

This would indicate that your sensor is really going south, just replace it, should be around $100.00 at your dealer.

I've been through 3 sensors already on one axle. These things can happen and the only way to fix it is a replacement (the sensor is put together with some Glue or composite)

Later on I'll check with the Bentley about your codes, sorry don't have it with me right now.

You could also check if this sensor is still mounted in a correct vertical position (compare to the right side of vehicle), if a sensor got hit by debris or stones it could bent and give you false indicators(happened already to me).

TTYL....and good luck troubleshooting.

mikef

the fault codes weren't exactly the same, though, in your post.

If you can check the Bentley manual, I would really appreciate it.

I will do the test you suggest as soon as I can get the thing up on a jack.

Mike

Rally_nutcase_1982

00774 - Level Control System Sensor: Left Rear (G76)
Connector on left rear level control system sensor -G76-open

Cable between left rear level control system sensor -G76- and level control system control module -J197- malfunctioning
----------------------------------------------------
Solution:
J197 indicates a cable breakage between Terminal 15 and control module


- Troubleshooting using wiring diagram
Electrical Wiring Diagrams, Troubleshooting &Component Locations
- Replace left rear level control system sensor -G76-
================================================== ===
----------------------------------------------------

01771 - Contol Module for Headlight Range (J431)

Malfunction on headlight range control module -J431-
Solution:
- Check DTC Memory of the headlight range control module -J431-

In plain english - more troubleshooting required with the VAG, could lead to open or short circuit -> possible cause:
Open circuit or short circuit to B+ or Ground (GND) between left headlight beam adjusting motor -V48- and control module

It could also lead to a) faulty control module
b) faulty head light adjustment beam motor

in both cases - replacement recommended.

================================================== ==

Suspension Electronics troubleshooting:

The following measuring and other equipment is needed:

Adapter Set VAG1594

Hand-held multimeter VAG1526

Test Box VAG1598/35 with Y cable for connection to wiring harness and self leveling suspension system J197

18 pin connector layout:
1
Ground (GND) level control pressure sensor -G291-
2
Ground (GND) (switched) level control accumulator valve -N311-
3
Relay for compressor level control system -J403-
4
Ground (GND) (switched) Solenoid for level control system -N111-
5
Level control pressure sensor -G291-
6
Ground (GND) (switched) left front suspension strut valve -N148-
7
Positive (+) suspension-strut valves -N148-, -N149-, -N150-, -N151- and Level control accumulator valve -N311-
8
not assigned
9
Solenoid for level control system -N111-
10
Ground (GND) level control pump temperature sensor -G290-
11
Ground (GND) (switched) left rear suspension strut valve -N150-
12
Ground (GND) (switched) right rear suspension strut valve -N151-
13
Level control pump temperature sensor -G290-
14
Power supply (+5 V) level control pressure sensor -G291-
15
Ground (GND) (switched) right front suspension strut valve -N149-
16
not assigned
17
not assigned
18
Relay for compressor level control system -J403-
================================================== =====
50Pin connector layout

1
Ground (GND) Terminal 31 (Level control system control module -J197-)
2
Ground (GND) Terminal 31 (Level control system control module -J197-)
3
not assigned
4
Level control system control head -E281-
5
Level control system control head -E281- (High Button)
6
Signal "Door open" (from central locking system control module)
7
Terminal 50b of the ignition switch
8
not assigned
9
Speed signal (from instrument cluster)
10
Contact switch for the switchable rear fog lamp (Trailer information)
11
Headlight range control module -J431-
12
Left front level control system sensor -G78-
13
not assigned
14
Right front level control sensor -G289-
15
K cable
16
Anti-theft alarm system, control module central locking -J429-
17
Headlight Range Control Module -J431-
18
Indicator lamp for level control system -K134-
19
Left rear level control system sensor -G76-
20
Data-BUS (CAN-High)
21
Data-BUS (CAN-Low)
22
Power supply (5 V) right rear level control system sensor -G77-
23
Right rear level control system sensor -G77-
24
Not assigned
25
Battery + (Terminal 30) via Fuse 17
26
not assigned
27
not assigned
28
not assigned
29
not assigned
30
not assigned
31
not assigned
32
not assigned
33
Ground (GND) left rear level control system sensor -G76-
34
Ground (GND) right rear level control system sensor -G77-
35
not assigned
36
not assigned
37
Ground (GND) right front level control sensor -G289-
38
not assigned
39
not assigned
40
Ground (GND) left front level control system sensor -G78-
41
not assigned
42
not assigned
43
not assigned
44
not assigned
45
Power supply (5 V) for right front level control sensor -G289-
46
Power supply (5 V) for left rear level control system sensor -G76-
47
Power supply (5 V) for left front level control system sensor -G78-
46
not assigned
49
Terminal 15 of the Ignition switch
50
Battery + (Terminal 30) via Fuse 17

OK...that is getting too much...YGM with the Notes on troubleshooting the cable......Good Luck!!