Diagnostic Aids

An intermittent may be caused by a poor connection, rubbed through wire insulation or a broken wire inside the insulation. Inspect for the following conditions:

• Poor connection. Inspect the PCM harness and connectors for improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
• Damaged harness. Inspect the wiring harness for damage. If the harness appears to be okay, disconnect the PCM, turn the ignition ON and observe a voltmeter connected to the 3X reference circuit at the PCM harness connector while moving connectors and wiring harnesses related to the ICM. A change in voltage will indicate the location of the malfunction.
• Malfunctioning ignition coil. If carbon tracking is detected on any component replace that component and its mate. Remove the ignition coils and inspect the ignition control module and coils for cracks, carbon tracking, or other signs that indicate that the coil secondary circuit is arcing to the ICM or ICM wiring harness.
• Secondary ignition wires arcing to wiring harness.
• Secondary ignition wires for carbon tracking or other signs of damage.

Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.