Malfunction Indicator Lamp (MIL)

Malfunction Indicator Lamp (MIL), significance

If malfunctions are recognized by the Engine Control Module (ECM), they will be communicated to the instrument cluster through the CAN-Bus and indicated by switching on the Malfunction Indicator Lamp (MIL).







Location of MIL lamp

NOTE:
The MIL Lamp can be switched ON in the blinking or permanently ON mode. Check DTC memory in either case.
- Blinking: There is a malfunction which can cause damage to catalyst if driven in this condition. In this case the vehicle must not be driven using full performance!
- Permanently ON: There is a malfunction which will increase exhaust emissions. Check Engine and/or Transmission Control Modules.
- If the MIL Lamp does not light up, even though there is an engine running problem or a customer complaint, DTC memory must be checked, because malfunctions which do NOT switch the MIL Lamp ON immediately could still be stored.

Functional check:
- Switch ON ignition
- MIL Lamp must light-up.

If NO
- Check MIL lamp wiring / MIL lamp bulb using wiring diagram.

If OK:
- Check instrument cluster / ECM and replace.
- Erase DTC memory.
- Set Readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If MIL Lamp lights-up with ignition switched ON, continue as follows:
- Start engine and let run at idle
- MIL Lamp must go out after a few seconds

If NO
- Check DTC memory.

If NO malfunction stored:
- Check MIL lamp wiring using wiring diagram.

If OK:
- Check instrument cluster / ECM and replace.
- Erase DTC memory.
- Set Readiness code. Monitors, Trips, Drive Cycles and Readiness Codes