Self-Diagnostic System: Notes

The ECM is equipped with a self-diagnostic system, which detects system failures or abnormalities. When a malfunction occurs, ECM will illuminate the SERVICE ENGINE SOON light located on instrument panel. When malfunction is detected and light is turned on, a corresponding trouble code will be stored in ECM memory. To retrieve stored codes, see RETRIEVING CODES (NON-SCAN) in this article. Malfunctions are recorded as HARD FAILURES or as INTERMITTENT FAILURES.