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 (MI) Circuit Malfunction

### Diagnostic Fault Information

Circuit | Short to Ground | Open | 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 engine control module (ECM) 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 in the Run or Crank position.

• | The ignition voltage is between 9-18 volts.

• | DTC P0650 runs continuously when the ignition is ON.

### 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 more than 5 seconds.

### Action Taken when the DTC Sets

DTC P0650 is a Type B DTC.

### Conditions for Clearing the MIL/DTC

DTC P0650 is a Type B DTC.

### Reference Information

#### Schematic Reference

• | Instrument Cluster Schematics.

• | Engine Controls Schematics.

#### Connector End View Reference

Component Connector End Views

#### Electrical Information Reference

• | Connector Repairs

• | Circuit Testing

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References

### Circuit/System Verification

Using a scan tool, command the MIL light On and OFF.

### Circuit/System Testing

1. Ignition OFF.
2. Disconnect the MIL light harness connector at the ECM.
3. Ignition ON, engine OFF. Connect a 3A fusible link wire between the MIL light control circuit on the wiring harness connector at the ECM and a known ground.

⇒ | If MIL light illuminates, replace the ECM.

⇒ | If MIL does not illuminate, inspect the MIL light control circuit for an open/high resistance or a short to ground.

4. If all circuits test normal, replace the IPC.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Instrument Cluster Replacement.

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