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 provide an overview of each diagnostic category.

### DTC Descriptors

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 malfunction indicator lamp (MIL) is located on the instrument panel cluster (IPC). The MIL informs the driver that an emission system fault has occurred and that the engine control system requires service. The control module monitors the MIL control circuit for conditions that are incorrect for the commanded states of the MIL.

### Conditions for Running the DTC

• | The ignition is ON or the engine is operating.

• | The ignition 1 voltage is more than 10 volts.

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

### Conditions for Setting the DTC

#### P0650

The engine control module (ECM) detects the MIL control circuit is open, shorted to ground, or shorted to a voltage for more than 5 seconds.

### Action Taken When the DTC Sets

DTC P0650 is a Type B DTC.

### Conditions for Clearing the DTC

DTC P0650 is a Type B 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. Ignition ON, command the MIL ON and OFF with a scan tool. The MIL should turn ON and OFF when commanded.
2. 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 IPC indicators or gages are inoperative, refer to Symptoms - Instrument Panel, Gages and Console .
2. Ignition OFF, disconnect the harness connector at the ECM.
3. Ignition ON, observe the MIL. The MIL should not illuminate.

⇒ | If the MIL illuminates, test the MIL control circuit for a short to ground. If the circuit tests normal, replace the IPC.

4. Connect a 3-A 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 an open/high resistance. If the circuit tests normal, replace the bulb or the IPC.

⇒ | If the fuse opens, test the MIL control circuit for a short to voltage.

5. If the MIL illuminates and all the circuits test normal, test for a poor connection at the ECM.

⇒ | If the connection tests normal, 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