Malfunction Indicator Lamp (MIL) Significance

Significance Of Malfunction Indicator Lamp (MIL)

If the ECM recognizes malfunctions that lead to a worsening of emissions values, it indicates them by lighting the Malfunction Indicator Lamp (MIL).

Installation position of MIL






NOTE: The Malfunction Indicator Lamp (MIL) can either blink or remain lit continuously. DTC memory should be checked in both cases.
- Blinking: There is a malfunction that can cause damage to the catalytic converter (e.g. combustion misfire). In this case, vehicle must only be driven at reduced power!
- Continuously lit: There is a malfunction that causes increased emissions. Check DTC memory for Motronic ECM and automatic transmission (if equipped).
- If there are driveability problems or if there is a customer complaint and the MIL is not lit, DTC memory must be checked. There may be DTCs stored that do not cause the MIL to light up immediately, but only if the malfunction is recognized again after repeated engine starts.