Malfunction Indicator Lamp: Testing and Inspection

Malfunction Indicator Lamp (MIL) Diagnosis

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

Ignition voltage is supplied to the malfunction indicator lamp (MIL). The engine control module (ECM) turns the MIL ON by grounding the MIL control circuit.

Reference Information
Schematic Reference

Engine Controls Schematics (LUW) [1][2]Electrical Diagrams
Connector End View Reference

Component Connector End Views Sunshade - Left (D6I)
Electrical Information Reference

* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Control Module References

Circuit/System Verification

Ignition ON, the MIL should turn ON and OFF when commanded with a scan tool.

Circuit/System Testing

1. Ignition ON, verify that the P16 Instrument Cluster warning indicators are illuminated.

• If the P16 Instrument Cluster warning indicators are not illuminated, test the P16 Instrument Cluster ignition circuit terminal 31 for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, replace the P16 Instrument Cluster.

2. Ignition OFF, disconnect connector X1 at the K20 Engine Control Module.
3. Ignition ON, verify that the MIL is not illuminated.

• If the MIL is illuminated, inspect the MIL control circuit K20 Engine Control Module terminal 68 (X1) for a short to ground. If the circuit tests normal, replace the P16 Instrument Cluster.

4. Verify that the MIL illuminates with a 3 A fused jumper wire between the MIL control circuit K20 Engine Control Module terminal 68 (X1) and ground.

• If the MIL does not illuminate, test the MIL control circuit K20 Engine Control Module terminal 68 (X1) for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

* Instrument Cluster Replacement Service and Repair
* Control Module References Control Module References