With Generic Scan Tool

MALFUNCTION INDICATOR LAMP (MIL), SIGNIFICANCE

If malfunctions are recognized by the Engine Control Module (ECM), they will be indicated by switching on the MIL.





Location of MIL.

NOTE: The MIL can be switched on in the flashing or permanently on mode. The Diagnostic Trouble Code (DTC) memory must be checked in every case.

- Flashing: There is a malfunction which can cause damage to Three Way Catalytic Converter (TWC) if driven in this condition. In this case the vehicle must not be driven using wide open throttle, but with partial throttle only, during which the MIL is continuously illuminated rather than flashing.

- Permanently on: There is a malfunction which will increase exhaust emissions. Check engine and/or automatic transmission control modules.

- MIL does not light up: If there is an engine running problem, or a customer complaint of one, perform a functional check of the MIL. Then, DTC memory must be checked because malfunctions which do not switch the MIL on immediately can also be stored.

Functional test:
- Switch ignition on:

- The MIL must light-up.

If the MIL does not light-up with ignition switched on:
- Check wiring to MIL as follows:





If the MIL lights-up with ignition switched on, continue check as follows:
- Start engine and run at idle:

- The MIL must go out after a few seconds.

If the MIL does not go out:
- Connect generic Scan Tool (ST), and check if there is a malfunction in DTC memory.

If no malfunction is stored: