Suspension - Erroneous Flat Tire Warning Message
SI B 36 01 06Wheels and Tires
March 2006
Technical Service
SUBJECT
Erroneous Flat Tire Warning
MODEL
E53 (X5 SAV) equipped with single axle air suspension (EHC SA220) produced from 4/04 to 1/06
SITUATION
Under certain circumstances, vehicle load conditions combined with individual customer driving habits, a regulation of the EHC may interfere with the wheel speed signals, resulting in an erroneous flat tire warning. In these cases, no fault code is stored in the Dynamic Stability Control module (DSC).
CAUSE
^ Incorrect ride height setting.
^ Communication error between the EHC and DSC modules.
CORRECTION
In case of a customer complaint, the DSC control module should be individually coded with Progman V20.2 or higher.
The improved coding allows the DSC control module to recognize EHC activations and thereby avoid false FTM warnings. Please refer to SI B36 05 05 for additional information on Flat Tire Monitor system.
PROCEDURE
1. Check for correct tire pressure settings. To ensure the proper operation of the FTM system always set the tire pressures according to the B pillar label or the chart contained in the Owner's Manual.
2. Check the vehicle ride height. If necessary perform the ride height calibration as per Repair Instructions RA 37 12 012.
3. Perform individual coding of the DSC control module using Progman V20.2 or higher. Do not perform a complete vehicle coding as the DSC control module may not be properly coded. To code the DSC module you must use the standard diagnostic head hardwired to the SSS station. Once you have established a connection with the diagnostic head please follow these steps from the Progman main menu.
^ Select "Load Software"
^ Select "X" from the list of vehicles
^ Select "E53"
^ Select "No" for "Have control modules been replaced on this car?"
^ Select "DSC" in the control modules list
^ Select "Encoding"
^ Select "Start" to complete the measures plan
4. Reset the Flat Tire Monitor system per instructions provided in the vehicles Owner's Manual.
WARRANTY INFORMATION
For information only.
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