Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 Chevrolet Tahoe, 2003 Chevrolet Suburban, and 2003 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

Important: When the DTC is current, the internal power relay of the rear wheel steering control module is turned OFF, which in turn shuts down the 12-volt reference to the SWPS. This results in all digital signals being displayed as low by the scan tool. Battery voltage and hall sensor reference voltage will also display low voltage. Cycling the ignition will cause the DTC to become a history code. When the DTC is a history code, the power relay is ON with ignition ON, and the 12-volt reference is supplied to the SWPS. During diagnosis, any steps that require monitoring data must be performed when the code is not current. Monitoring data while the DTC is current will result in inaccurate data being displayed, and misdiagnosis will result.

The following conditions are possible causes:

A class 2 communication problem with the TBC.
The steering wheel was rotated with the steering gear disconnected.
A malfunctioning steering wheel position sensor is present.
A steering wheel position sensor circuit is open.
A steering wheel position sensor circuit was shorted.

Perform an inspection of the wiring and of the connectors. Failure to carefully inspect the wiring and the connectors may result in misdiagnosis. Misdiagnosis causes part replacement with reappearance of the malfunction.