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.

Inspect for poor connections at the harness connector of the rear wheel steering control module and inspect the wiring harness. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS , and to CONNECTOR REPAIRS in Wiring Systems.
Observe the rear wheel steering mode select switch. If all of the mode indicator LEDs are illuminated the rear wheel steering control module has lost its memory settings and the scan tool must be used to re-calibrate the rear wheel steering alignment data in the rear wheel steering control module. Refer to MEASURING WHEEL ALIGNMENT (WITH REAR WHEEL STEERING) or MEASURING WHEEL ALIGNMENT (WITHOUT REAR WHEEL STEERING) .