Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2002 Pontiac Grand Prix, 2002 Pontiac Bonneville, 2002 Chevrolet Monte Carlo, 2002 Chevrolet Impala, and 2002 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.

Check for the following conditions:

Poor connection at PCM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
Damaged harness. Inspect wiring harness for damage. If harness appears to be okay, observe MAP display on scan tool with ignition on, engine off while moving connectors and wiring harnesses. A change in MAP display will indicate location of malfunction.

Reviewing freeze frame/failure records will indicate vehicle mileage since diagnostic test last failed. This may help determine how often condition that caused DTC to be set occurs. This may assist in diagnosing condition.