Diagnostic Trouble Codes: Notes

WARNING: This page is about a different car, the 1998 GMC Forward Control and 1998 Chevrolet Forward Control. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: In the following tests, illustrations are courtesy of General Motors Corp.

NOTE: Before clearing DTCs, record FREEZE FRAME and FAILURE RECORDS for reference during testing. Data will be erased when DTCs are cleared.

NOTE: If PCM is replaced, NEW PCM must be programmed using special equipment.