Ignition voltage is supplied directly to the malfunction indicator lamp (MIL). The engine control module (ECM) turns the MIL ON. The MIL should be on steady with the ignition ON and the engine OFF. When the engine is started, the MIL should turn OFF.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Instrument Cluster Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, observe the DTC information with a scan tool. Verify that no DTC is set.

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

2. Cycle ignition ON and OFF, the MIL should turn On and OFF with each cycle.

⇒	If the MIL does not respond properly, refer to the Circuit/System Testing.

1. Ignition OFF, disconnect the harness connector at the P16 Instrument Panel Cluster (IPC).
2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 31 and ground.

⇒	If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test all the components connected to the ignition circuit and replace as necessary.

3. Connect a test lamp between the control circuit terminal 25 and B+. The test lamp should not illuminate.

⇒	If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit test normal, replace the K20 Engine Control Module (ECM).

4. Ignition OFF, connect the harness connector to the P16 Instrument Panel Cluster (IPC)
5. Disconnect X2 the harness connector at the K20 Engine Control Module (ECM).
6. Connect a 3 A fused jumper wire between the control circuit terminal 25 (X2) and ground. The test lamp should illuminate.

⇒	If the test lamp is always OFF, test the control circuit for an open/high resistance or a short to ground. If the circuit test normal, replace the K20 Engine Control Module (ECM).

7. If all circuit tests normal, replace the P16 Instrument Panel Cluster (IPC).

Perform the Diagnostic Repair Verification after completing the repair.