Trouble Code Charts: Notes

WARNING: This page does not describe the selected car, but rather 23 other vehicles, including the 1991 GMC Vandura Special, 1991 GMC Vandura, 1991 GMC Value Van, 1991 GMC Suburban, and 1991 GMC Rally Camper Special. However, it is still accessible from the selected car via links, so may be relevant.

The following diagnostic flow charts and circuit schematics are provided courtesy of General Motors Corp.

NOTE: Some charts require the use of a bidirectional (Tech 1) Scan tester. If a bidirectional Scan tester is not available, the PCM/TCM-controlled relays and solenoids may be energized by grounding ALDL test terminal "B" with ignition on and engine off.