Engine Controls Self-Diagnostics - Introduction: Summary

If the MIL does not illuminate, indicating a Diagnostic Trouble Code (DTC) has been set and there is a driveability malfunction, go to TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures. Some trouble shooting steps may require resetting PCM and attempting to duplicate DTC. If malfunction is intermittent and DTC cannot be duplicated, discontinue trouble shooting procedures and go to TROUBLE SHOOTING - NO CODES article for diagnosis by symptom. If DTC cannot be duplicated, continuing with trouble shooting procedures will cause confusion and could result in unnecessary component replacement.