▶ Check for poor connection between ECM/PCM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection. Repair as necessary and go to "Verification of Vehicle Repair" procedure.

▶ Check ECM/PCM for contamination, deterioration, or damage. Substitute with a known-good ECM/PCM and check for proper operation. If the problem is corrected, replace ECM/PCM and then go to "Verification of Vehicle Repair" procedure.