Malfunction Indicator Light (Mil): Notes

Vehicles are equipped with a Malfunction Indicator Light (MIL). As a bulb check, light will illuminate for approximately 5 seconds when ignition is on. MIL will also illuminate when a system failure is detected; a corresponding trouble code will set in Electronic Control Module (ECM) memory.

ECM is equipped with a self-diagnostic system, which detects system failures or abnormalities. When a malfunction occurs, ECM will illuminate MIL (CHECK ENGINE light) on instrument panel. When malfunction is detected and light is turned on, a corresponding trouble code will be stored in ECM. To retrieve stored codes, see RETRIEVING CODES (NON-SCAN)  or RETRIEVING CODES (SCAN TESTER)  . Malfunctions are recorded as hard failures or as intermittent failures.