Malfunction Indicator Lamp (MIL) Diagnosis

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

* Instrument Cluster Schematics Instrument Cluster Schematics

* Engine Controls Schematics (LZ1) [1][2]Electrical Diagrams

Connector End View Reference

Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)

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 for scan tool information

Circuit/System Verification

1. Ignition ON, command the MIL ON and OFF with a scan tool. The MIL should turn ON and OFF.

2. Engine idling, command the MIL ON and OFF with a scan tool while observing the following control circuit status parameters:

* MIL Circuit Short to Gnd Test Status

* MIL Circuit Open Test Status

* MIL Circuit Short to Voltage Test Status

Each parameter should toggle between OK and Not Run or Not Run and OK.

Circuit/System Testing

1. Ignition OFF, open the hood to disable the Auto-Stop function. Refer to Hybrid Modes of Operation Description Hybrid Modes of Operation Description.

2. Ignition ON, verify the scan tool hood position parameter displays Open.

• If the hood position does not display Open, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle for DTC P254F.

3. Ignition ON, verify that the instrument panel cluster (IPC) warning indicators are illuminated.

• If the IPC warning indicators are not illuminated, 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, replace the IPC.

4. Ignition OFF, disconnect harness connector X1 at the ECM.

5. Ignition ON, verify the MIL is not illuminated.

• If the MIL is illuminated, test the MIL control circuit for a short to ground. If the circuit tests normal, replace the IPC.

6. Connect a 3 A fused jumper wire between the MIL control circuit terminal 12-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 tests normal, replace the IPC.

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

Repair Instructions

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

* Instrument Cluster Replacement (With RPO SLT) Instrument Cluster Replacement (With RPO SLT)Instrument Cluster Replacement (Without RPO SLT) Instrument Cluster Replacement (Without RPO SLT)

* Control Module References Control Module References for ECM replacement, setup, and programming