Malfunction Indicator Lamp: Testing and Inspection

Malfunction Indicator Lamp (MIL) functional, check

- Switch ignition on.
MIL must light UP.
- If MIL does not light when ignition is switched on, check wiring to MIL as follows.

Cause:
MIL is not triggered, or does not light, due to faulty wiring or open circuit.

Corrective action:
- Switch ignition off.
- Connect VAG 1598/22 test box
- Connect jumper wire to bridge test box sockets 2 and 17.
- Switch ignition on.
- MIL must light up.
If MIL does not light:
- Switch ignition off.
- Check bulb for MIL.
If bulb is OK:
- Check wiring for open circuit between MIL and Motronic ECM -J220- using applicable wiring diagram.
If wiring is OK:

Malfunction:
Motronic ECM -J220- is faulty; Check and erase Diagnostic Trouble Code (DTC) memory and generate new readiness code. Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/Connecting VAG 1598/22 Test Box" Testing and Inspection

If MIL lights up when ignition is switched on, continue checking as follows:
- Start engine and let run at idle.

MIL must go out after a few seconds.

If MIL does not go out:
- Check Diagnostic Trouble Code (DTC) memory.

If there are no malfunctions stored in DTC memory:

Cause:
MIL is triggered continuously due to short circuit to Ground.

Corrective action:
- Switch ignition off.
- Connect VAG 1598/22 test box.
- Check resistance between test box socket 17 and vehicle Ground, specified value: Infinity Ohms (no continuity)
If the specified value is not obtained:
- Check for short circuit to Ground in wiring from Motronic Engine Control Module (ECM) -J220- to MIL.
- Trace malfunction using applicable wiring diagram and repair as necessary.
If there is no continuity, and no short circuit to Ground:

Malfunction:
Motronic ECM -J220- is faulty; replace. Check and erase Diagnostic Trouble Code (DTC) memory and generate new readiness code.Refer to "Moniters, Trips and/or Drive Cycle (Readiness Codes)/Generating Readiness Code Testing and Inspection