Test Description

WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The number below refers to the step numbers on the diagnostic table.

6) - The module which was not communicating on the class 2 serial data circuit may have set Loss of Communicating DTCs for those modules that it was monitoring.

Fig 1: DTC U1001-U1254 Diagnosis (Steps 1-5)

Courtesy of GENERAL MOTORS CORP.

Fig 2: DTC U1001-U1254 Diagnosis (Steps 6-8)

Courtesy of GENERAL MOTORS CORP.