Self-Diagnostic System: Notes

WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1995 GMC Yukon, 1995 GMC Suburban, 1995 GMC Pickup, 1995 GMC Cab & Chassis, and 1995 GMC C3500 HD. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: SERVICE ENGINE SOON light, located on instrument cluster, is also referred to as the Malfunction Indicator Light (MIL).

NOTE: Unless specifically stated otherwise, references to PCM also apply to TCM-equipped vehicles.

The 6.5L DEC/electronically-controlled transmission systems includes a self-diagnostic system which can determine input signal circuit malfunctions. Input signal circuits determine engine/transmission function control. When a malfunction occurs, PCM/TCM will illuminate the Malfunction Indicator Light (MIL) located on instrument cluster. When malfunction is detected and light is turned on, a corresponding Diagnostic Trouble Code (DTC) will be stored in PCM/TCM memory. To retrieve stored codes, see ENTERING & EXITING DIAGNOSTIC MODE . Malfunctions are recorded as either hard failures or intermittent failures.