Malfunction Indicator Lamp (MIL)

Exhaust Gas Warning Lamp MIL (Malfunction Indicator Lamp), Significance

If malfunctions are recognized by the engine control module, they will be indicated by switching on the Malfunction Indicator Lamp (MIL).







Location of Malfunction Indicator Lamp (MIL)


NOTE:
The Malfunction Indicator Lamp (MIL) can be switched on in the flashing or permanently on mode. The DTC memory must be checked in every case.
- Flashing: 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 emission. Check Motronic and/or automatic transmission control modules.
- If the Malfunction Indicator Lamp (MIL) does not light up, even though there is an engine running problem, or a customer has complained, the DTC memory must be checked, because malfunctions which do not switch the Malfunction Indicator Lamp (MIL) on immediately can also be stored.


Functional check:
- Switch ignition on: Malfunction Indicator Lamp (MIL) must light-up.

If the Malfunction Indicator Lamp (MIL) does not light-up with ignition switched on:
- Check combi-instrument and EPC warning lamp as follows:

If the Malfunction Indicator Lamp (MIL) lights-up with ignition switched on, continue check as follows:
- Start engine and run at idling speed: Malfunction Indicator Lamp (MIL) must go out after a few seconds.

If the Malfunction Indicator Lamp (MIL) does not go out:
- Check DTC Memory, if necessary, repair any malfunctions and then Erase DTC Memory, checking and erasing DTC Memory.
- Read readiness code. If the DTC memory has been erased or the engine control module was disconnected from permanent positive, the readiness code must be generated again:
Monitors, Trips, Drive Cycles and Readiness Codes
Engine code AWW, Monitors, Trips, Drive Cycles and Readiness Codes
Engine code AWP, Monitors, Trips, Drive Cycles and Readiness Codes