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.

### DTC Descriptor

DTC P0650: Malfunction Indicator Lamp (MIL) Control Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
MIL Voltage Supply | P0650 | P0650 | -- | --
MIL Control | P0650/MIL ON | P0650 | P0650 | --

### Circuit/System Description

The MIL is located on the instrument panel (IP) cluster. Ignition 1 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.

### Conditions for Running the DTC

• | The engine is operating.

• | The ignition 1 voltage is between 7.5-16 volts.

• | The DTCs runs continuously once the above conditions are met.

### Conditions for Setting the DTC

The ECM detects the MIL control circuit is open or shorted to ground or voltage.

### Action Taken When the DTC Sets

DTC P0650 is a Type C DTC.

### Conditions for Clearing the DTC

DTC P0650 is a Type C DTC.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

• | Engine Control Module Connector End Views

• | Engine Controls Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

• | Scan Tool Data List

• | Scan Tool Data Definitions

• | Scan Tool Output Controls

### Circuit/System Verification

1. Engine idling, command the MIL ON and OFF with a scan tool. The MIL should turn ON and OFF.
2. Observe the DTC information with a scan tool. DTC P0650 should not set.
3. If the vehicle passes the Circuit/System Verification Test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.

### Circuit/System Testing

1. If any other indicators are inoperative on the instrument panel (IP) cluster, refer to Symptoms - Instrument Panel, Gages and Console .
2. Ignition OFF, disconnect the ECM harness connector.
3. Ignition ON, the MIL should not illuminate.

⇒ | If the MIL illuminates, test the MIL control circuit for a short to ground. If the circuit test normal, replace the instrument panel (IP) cluster.

4. Ignition ON, connect a 3-amp fused jumper wire between the MIL control circuit 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 instrument panel (IP) cluster.

⇒ | If the MIL illuminates, inspect for a poor connection or replace the ECM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Instrument Cluster Replacement

• | Control Module References for engine control module replacement, setup, and programming