Malfunction Indicator Lamp (MIL) In Instrument Cluster, Checking

Malfunction Indicator Lamp (MIL) in instrument cluster, checking

Meaning of emissions system MIL

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






Emissions system MIL

Note: The Malfunction Indicator Lamp (MIL) can blink or remain lit continuously. The DTC memory must be checked in each case.

- Blinking: There is a malfunction that causes damage to the catalytic converter in this driving condition. 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 control module.
- DTC memory must still be checked if there are driveability 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 and equipment
- VAG 1526 multimeter or VAG 1715 multimeter
- VAG 1594 connector test kit
- Wiring diagram

Test requirement






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

Test sequence

- Switch on ignition.

Emissions system MIL must light up.

If emissions system MIL does not light up when ignition is switched on:

- Switch ignition off.

- Check wire from ECM to emissions system MIL as follows:

- Connect test box to control module wiring harness.

- Bridge sockets 2 & 47 of test box with the respective adapter cables.

- Switch on ignition.

Emissions system MIL must light up.

If Malfunction Indicator Lamp (MIL) does not light up:

- Switch ignition off.

- 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 Engine Control Module (ECM).

- 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 emissions system MIL lights up when ignition is switched on:

- Start engine and let run at idle.

Emissions system MIL must go out after a few seconds.

If Malfunction Indicator Lamp (MIL) does not go out:

- Switch ignition off.

- Remove instrument cluster.

- Connect test box to control module wiring harness.

- 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 Engine Control Module (ECM).

- 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-.