Ignition voltage is supplied directly to the malfunction indicator lamp (MIL). The engine control module (ECM) turns the MIL ON by grounding the MIL control circuit. There should be a steady MIL with the ignition ON and the engine OFF.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

Scan Tool Reference

Control Module References Control Module References for scan tool information

1. Ignition ON, engine OFF, observe the transmission DTC information with a scan tool. There should be no transmission DTCs set.

⇒	If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.

2. Command the MIL ON and OFF with a scan tool. The MIL should turn ON and OFF when commanded.
3. Engine idling, command the MIL ON and OFF with a scan tool while observing the following control circuit status parameters:

•	MIL Ckt Short Gnd Test Status

•	MIL Ckt Open Test Status

•	MIL Ckt Short Volts Test Status

•	Each parameter should display OK or Not Run.

1. If any other indicators are inoperative, refer to Symptoms - Displays and Gages.
2. Ignition OFF, disconnect the ECM harness connector X1.
3. Ignition ON, the MIL should not illuminate.

⇒	If the MIL illuminates, test the MIL control circuit terminal 1-X1 for a short to ground. If the circuit test normal, replace the bulb/IPC.

4. Ignition ON, connect a 3 A fused jumper wire between the MIL control circuit terminal 1-X1 and ground. The MIL should illuminate.

⇒	If the MIL does not illuminate, test the MIL control circuit for a short to voltage or an open/high resistance. If the circuit test normal, replace the bulb/IPC.

5. If all circuits test normal, replace the ECM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.