Malfunction Indicator Lamp, Checking

Malfunction Indicator Lamp, Checking

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







Malfunction Indicator Lamp (MIL) installation location

NOTE:
- The Malfunction Indicator Lamp (MIL) may blink or remain lit continuously. DTC memory must be checked in each case. Diagnostic Mode 03 - Read DTC Memory
- Blinking: A malfunction exists that, under these driving conditions, may damage the catalytic converters. In this case, vehicle must only be driven at reduced load performance.
- Continuous light: A malfunction exists that causes increased emissions. Check DTC memory for Motronic control module.
- DTC memory must still be checked if there are drivability 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.

Recommended Special Tools, Workshop Equipment, Testers, Measuring Instruments and Auxiliary Items
- V.A.G 1526 portable multimeter or V.A.G 1715 multimeter
- Adapter set V.A.G 1594
- Wiring diagram

Test Conditions
- The respective fuses of Malfunction Indicator Lamp (MIL) -K83- must be OK

Test Sequence
- Switch ignition on:

Malfunction Indicator Lamp (MIL) must come on.

If MIL does not come on when ignition is switched on:
- Switch off ignition.
- Check wires from ECM to exhaust MIL as follows:
- Connect test box to control module wiring harness. Test Box, Connecting For Wiring Test
- Bridge sockets 2+47 of test box with the respective adapter cables.
- Switch ignition on:

Malfunction Indicator Lamp (MIL) must come on.

If MIL does not come on:
- Switch off ignition.
- Remove instrument cluster
- Check wire connection from Engine Control Module (ECM) to Malfunction Indicator Lamp (MIL) -K83- according to wiring diagram

- Erase DTC memory of ECM. Diagnostic Mode 04 - Erase DTC Memory
- Generate readiness code. Generate Readiness Code

If no malfunctions are detected in wire from Engine Control Module (ECM) to Malfunction Indicator Lamp (MIL):
- Replace Motronic Engine Control Module (ECM) -J220-.

If MIL does not come on when ignition is switched on:
- Start engine and let run at idle:

MIL must go off after a few seconds.

If MIL does not go out:
- Switch off ignition.
- Remove instrument cluster
- Connect test box to control module wiring harness. Test Box, Connecting For Wiring Test
- Check wire connection between test box socket 47 and instrument cluster for short circuit to Ground (GND) according to wiring diagram
- Erase DTC memory of ECM. Diagnostic Mode 04 - Erase DTC Memory
- Generate readiness code. Generate Readiness Code

If no malfunctions are detected in wire from Engine Control Module (ECM) to Malfunction Indicator Lamp (MIL):
- Replace Motronic Engine Control Module (ECM) -J220-.