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/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

• | DTCs P0601, P0604, P0605, P0606, P0607, and P2610 are not set.

• | 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 one second.

⇒ | Should a short circuit to B+ or an open circuit occur on the MIL control circuit, the MIL must be commanded ON for the DTC to set. A short circuit to ground failure on the MIL control circuit can be detected immediately by the ECM in the commanded OFF state.

### 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.

### Reference Information

#### Schematic Reference

• | Engine Controls Schematics

• | Instrument Cluster 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, the MIL should turn ON and OFF when commanded with a scan tool.
2. Operate the vehicle within the Conditions for Running the DTC. 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 connector X2 at the ECM.
3. Ignition ON, verify that the MIL is not illuminated.

⇒ | If the MIL is illuminated inspect the MIL control circuit for a short to ground. If the circuit tests normal, replace the IPC.

4. Ignition ON, verify that the MIL illuminates with a 3A fused jumper between the MIL control circuit X2-1 and ground.

⇒ | 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 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