Malfunction Indicator Lamp (MIL)

Malfunction Indicator Lamp (MIL)

The malfunction indicator lamp (MIL) alerts the driver that the PCM has detected an OBD II emission-related component or system fault. When this occurs, a DTC will be set
- The MIL is located on the instrument cluster and is labeled CHECK ENGINE.
- Power is supplied to the MIL whenever the ignition switch is In the ON or START position.
- The MIL will remain on in the ON/START mode as a bulb check during the instrument cluster proveout for approximately 4 seconds.
- If the MIL remains on after the bulb check
- The PCM illuminates the MIL for an emission- related concern and a DTC will be present.
- The instrument cluster will illuminate the MIL if the PCM does not send a control message to the instrument cluster.
- The PCM is operating in the Hardware Limited Operation Strategy (HLOS).
- The MIL circuit is shorted to ground.

- If the MIL remains off (during the bulb check):
- Bulb is damaged.
- MIL circuit is open

- To turn off the MIL after a repair, a reset command from the WDS or equivalent must be sent, or three consecutive drive cycles must be completed without a fault.
- If the MIL blinks at a steady rate, a severe misfire condition could possibly exist
- If the MIL blinks erratically. an intermittent open B+ to the bulb or an intermittent short to ground in the MIL circuit exist. Also the PCM can reset while cranking if battery voltage is low.