Electronic Control System: Self-diagnosis

When an abnormality occurs in the signal from a sensor, the ECM/PCM supplies ground for the Malfunction Indicator Lamp (MIL) and stores the Diagnostic Trouble Code (DTC) in erasable memory. When the ignition is first turned on, the ECM/PCM supplies ground to the MIL for 2 seconds ('98-01 models) or 15 to 20 seconds ('02 models) to check the MIL bulb condition.