According to VAG-COM I've had 76 instances of fault 01772.... Signal from Level Control Pressure Sensor (G291) Implausible Signal. MIL has come on twice, then gone off and no issues other than some compressor noise after the engine has been turned off etc. Doesn't sound bad at all, just occasionally adjusts for a while after the car has been switched off. But only happens very rarely rarely. Ross-Tech suggests looking at TSB 43-08-16, but can't find it anywhere.

Also has 2 instances of Error code 01577 Turn-off due to over temp, upper limit exceeded, but I suspect that is the compressor shutting off after working hard to keep the above problem in check....

Thoughts?

 

heres the main detail of it



Customer statement / workshop findings

Failure of the self-levelling system

- The self-levelling system cannot be adjusted any more with the MMI

- The compressor for the self-levelling system continues to run after switching off the engine and locking the vehicle.

Technical background

Because of poor performance or failure of the compressor for air suspension the vehicle position cannot be controlled any more.

One of the following entries may be logged:

0453 - restricted function through excess temperature

1583 - leak in the system recognised

1770 - sender for compressor temperature of self-levelling control G290

1772 - signal cable of pressure sender for self-levelling control G291

2645 - valves for self-levelling control

2646 - plausibility of self-levelling control


Check with a direct current supply the compressor for the self-levelling system.

See the current flow diagram for the location of the relay and of the compressor.


1.

If the compressor operates with a normal working noise, check the relay J403 of the compressor for the self-levelling system.

Open the relay and assess the contacts. Compare them with the contacts of illustrations 1 to 3. Is the wear is similar or are the burn marks in the housing?

If the contacts are as those on illustration 5, the relay is correct.

2.

If the self-levelling compressor doesn't work or with an unusually loud noise, it is highly likely that the compressor ran permanently.

Check the contacts of the relay J403 for burn marks and wear. Worn contacts are shown on illustration 1 to 3.

A discolouring of the strand is also a clear indication for a permanent operation of the compressor, see illustration 4.




Illustration 1.: strong erosion of both contacts




Illustration 2.: strong erosion of both contacts




Illustration 3.: strong erosion of the spring contact




Illustration 4.: overheated strand




Illustration 5.: contacts with minor marks - relay correct

Production change

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Measure

If the above points of 1. or 2. (illustrations 1-4) apply, replace the compressor and the relay J403 for self-levelling system.

If there only minor or no wear marks (see illustration 5) and the compressor has a similar working noise to a comparable vehicle, replace only the opened relay J403 for self-levelling system.