Suspension - Self-Leveling Can't Be Adjusted/DTC's Set
43 Self-leveling compressor inoperative
43 13 14
2018765/8
April 11, 2013
Supersedes Technical DIAGNOSIS AND REPAIR Group 43 number 12-11 dated October 29, 2012 for reasons listed below.
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Vehicle Information
Condition
^ The self-leveling system can no longer be adjusted with the MMI.
^ The compressor for the self-leveling system continues to run after the engine has been switched off and the vehicle has been locked.
^ One of the following DTCs may be stored in the level control system module, J197 (address word 34):
^ 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 air suspension compressor, the vehicle ride height 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
Not applicable.
Service
Tip:
See the current flow diagram for the location of the J403 relay for the air supply unit and the location of the air compressor (air supply unit).
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1. Check the function of the air compressor by supplying it with direct current. Determine if the air compressor is operating correctly and sounds
normal, if it is unusually noisy, or if it is not working at all.
2. Check relay J403 by opening the relay and comparing it to the images shown:
If the relay exhibits any of the conditions A - C below, replace both the air compressor and the relay, even if the air compressor sounds normal.
A) Strong erosion of both contacts (Figure 1, Figure 2).
B) Strong erosion of the spring contact (Figure 3).
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C) Overheated strand (Figure 4).
If the relay contacts are similar to condition D below, and the air compressor sounds normal, replace only the relay.
D) Contacts with minor marks (Figure 5).
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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.
