Malfunction Indicator Lamp, Significance

The Malfunction Indicator Lamp (MIL) lights up when malfunctions are recognized by the Engine Control Module (ECM).





Installation position of exhaust MIL

NOTES:
The Malfunction Indicator Lamp (MIL) can blink or be lit continuously. DTC memory should be checked in both cases. Refer to "On Board Diagnostic". Testing and Inspection
- Blinking: There is a malfunction that damages the catalytic converter in this driving condition. In this case, vehicle must only be driven at reduced power!
- Steady light: There is a malfunction that causes increased emissions. Check DTC memory for Motronic ECM or automatic transmission.
- DTC memory must still be checked if there are drive ability problems or the customer has made a complaint but the MIL is not lit, because malfunctions can be stored without causing the MIL to light immediately.


Function test:
- Switch on ignition:
exhaust MIL must light.

If exhaust MIL does not light when ignition is switched on:
- Check instrument cluster and Malfunction Indicator Lamp (MIL).

If exhaust MIL does not light when ignition is switched on, continue test as follows:
- Start engine and let run at idle:
Exhaust MIL must go out after a few seconds.

If exhaust MIL does not go out:
- Check DTC memory, repair any malfunctions and then erase DTC memory See Erasing and checking DTC memory. Refer to "On Board Diagnostic". Testing and Inspection
- Read readiness code. Refer to "On Board Diagnostic". Testing and Inspection
If DTC memory was erased or the Engine Control Module (ECM) was disconnected from the continuous B+ supply, the readiness code must be re-generated. Refer to "On Board Diagnostic". Testing and Inspection