Diagnostic Procedures

If diagnostic system check was not performed, perform ENGINE ELECTRICAL DIAGNOSTIC SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. If diagnostic system check was performed, go to next step.
Install scan tool. Start engine. With scan tool, monitor the DTC information for DTC P0621 in Engine Controls. Does the scan tool indicate that DTC P0621 has passed? If yes, check for intermittent and poor connections in wiring system. If no, go to next step.
Test the generator turn on signal circuit for a short or open. Did you find and correct the condition? If yes, go to step 6 . If no, go to next step.
Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step 6 . If no, go to next step.
Replace PCM. See REMOVAL, OVERHAUL & INSTALLATION - CARS article in ENGINE PERFORMANCE. Program PCM. After repair, go to next step.
Review and record scan tool Fail Records data. Using scan tool, clear DTCs. Start engine. Using scan tool, observe Specific DTC Information for this DTC until test runs. If scan tool indicates that this DTC failed this ignition cycle, repeat test beginning at step 2 . If scan tool indicates that this DTC passed this ignition cycle, system is okay.