Electronic Control System: Self-diagnosis

When an abnormality occurs in the signal from a sensor, the 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 PCM supplies ground to the MIL for 2 seconds ('99-01 models) or for 15 to 20 seconds ('02-04 models) to check the MIL bulb condition.