For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### Circuit/System Description

Ignition 1 voltage is supplied directly to the malfunction indicator lamp (MIL). The engine control module (ECM) turns the MIL ON by sending a request to the instrument panel cluster (IPC) via the CAN communication circuit. The MIL should be on steady with the ignition ON and the engine OFF. When the engine is started, the MIL should turn OFF.

### Reference Information

#### Schematic Reference

Instrument Cluster Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Instrument Cluster Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Ignition ON, observe the DTC information with a scan tool. Verify that DTC U0100, U0155, or U2105 is not set.

⇒ | If any of the DTCs are 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 with each command.

⇒ | If the MIL does not respond properly, replace the IPC.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for Instrument Panel Cluster replacement, setup, and programming