Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2003 GMC Savana Special, 2003 GMC Savana Camper Special, 2003 GMC Savana, 2003 Chevrolet RV Cutaway, and 2003 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

This DTC may be stored as a history DTC without affecting the operation of the module. If stored only as a history DTC and not retrieved as a current DTC, do not replace the module.
If this DTC is retrieved as both a current and history DTC, replace the module.

Fig 1: DTC C0550

Courtesy of GENERAL MOTORS CORP.