Diagnostic Aids
WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Check all connections between the IPC and the rear wheel steering control module for loose or damaged terminals or damaged wiring. Use of the Diagnostic System Check will help ensure that there are not other conditions or DTC's that will cause a loss of communication between modules.