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 Descriptor

DTC P0650: Malfunction Indicator Lamp (MIL) Control Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open | Short to Voltage
--- | --- | --- | ---
MIL Voltage Supply | P0650 | P0650 | --
MIL Control | P0650* | P0650 | P0650
*The MIL remains ON

### 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 engine control module (ECM) monitors the MIL control circuit for conditions that are incorrect for the commanded states of the MIL. For example, a failure condition exists if the ECM detects low voltage when the MIL is commanded OFF, or high voltage when the MIL is commanded ON.

### Conditions for Running the DTC

DTC P0650 runs continuously when the ignition is ON and the ignition voltage is between 11-18 volts.

### Conditions for Setting the DTC

The ECM detects that the commanded state of the MIL driver and the actual state of the control circuit do not match for 6 seconds.

### Action Taken When the DTC Sets

DTC P0650 is a Type B DTC, with no MIL request.

### Conditions for Clearing the MIL/DTC

DTC P0650 is a Type B DTC, with no MIL request.

### Diagnostic Aids

If the condition is intermittent, move the related harnesses and connectors with the engine operating. Monitor the scan tool Circuit Test Status parameters for the component. The Circuit Test Status parameter will change from OK or Not Run to Fault if there is a condition with the circuit or a connection.

### Reference Information

#### Schematic Reference

• | Instrument Cluster Schematics

• | Engine Controls Schematics

#### Connector End View Reference

Component 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

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 as commanded.
2. Command the MIL ON and OFF with a scan tool while observing the following control circuit status parameters:

• | MIL Ckt. Short Gnd Test Status

• | MIL Ckt. Open Test Status

• | MIL Ckt. Short Volts Test Status

| Each parameter should change from OK and Not Run or from Not Run and OK.

3. Operate the vehicle within the Conditions for Running the DTC to verify that the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

### Circuit/System Testing

1. Ignition ON, verify that the 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.

2. Ignition OFF, disconnect ECM X1 harness connector. Ignition ON, the MIL should not illuminate.

⇒ | If the MIL is illuminated, test the MIL control circuit terminal X1-12 for a short to ground. If the circuit tests normal, replace the IPC.

3. Ignition ON, connect a 3A fused jumper wire between the MIL control circuit terminal X1-12 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/bulb.

4. If all circuits/connections test normal, replace the ECM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Instrument Cluster Replacement

• | Control Module References for ECM replacement, setup, and programming