Suspension - Unable To Adjust Level/Multiple DTC's Set
43 Self-leveling compressor inoperative43 09 10
2018765/4
October 27, 2009.
Supersedes Technical Service Bulletin Group 43 number 08-16 dated December 11, 2008 for reasons listed below.
Affected Vehicles
Condition
^ The self-leveling system cannot be adjusted any more with the MMI.
^ The compressor for the self-leveling system continues to run after switching off the engine and locking the vehicle.
^ One of the following DTCs may be stored:
^ DTC 0453 (restricted function through excess temperature).
^ DTC 1583 (leak in the system recognized).
^ DTC 1770 (sender for compressor temperature of self-leveling control G290).
^ DTC 1772 (signal cable of pressure sender for self-leveling control G291).
^ DTC 2645 (valves for self-leveling control).
^ DTC 2646 (plausibility of self-leveling control).
Technical Background
Because of poor performance or failure of the compressor for air suspension, the vehicle position cannot be adjusted. As a safeguard, the control module will lower the vehicle to the lowest position and illuminate the warning light. Drivability is not affected.
Production Solution
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Service
1. Use a direct current supply to check the compressor for the self-leveling system.
2. See the current flow diagram for the locations of the relay and the compressor.
3. Check the relay J403 of the compressor for the self-leveling system.
4. Open the relay and assess the contacts. Compare them with the contacts of Figures 1 to 3.
Is the wear is similar, or are there burn marks in the housing?
If the relay resembles Figures 1 to 3, replace the compressor and relay J403 for the self-leveling system.
5. Discoloring of the strand is also a clear indication of permanent operation of the compressor (Figure 4).
Replace the compressor and relay J403 for the self-leveling system.
6. If the contacts resemble those in Figure 5 and the compressor has a working noise similar to a comparable vehicle, replace only the opened relay J403 for the self-leveling system.
Warranty
Additional Information
All parts and service references provided in this TSB are subject to change and/or removal. Always check with your Parts Department and service manuals for the latest information.