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*	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 state 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

•	The engine speed is more than 80 RPM.

•	The ignition voltage is between 10-18 V.

•	The ECM has commanded the MIL ON and OFF at least once during the ignition cycle.

•	DTC P0650 runs continuously when the above conditions are met.

Conditions for Setting the DTC

The ECM detects an open, a short to ground, or a short to voltage on the circuit that controls the MIL.

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.

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

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.	Ignition ON, observe each of the MIL Control Circuit Test parameters listed below with a scan tool:

•

The MIL Control Circuit Low Voltage Test Status

•

The MIL Control Circuit Open Test Status

•

The MIL Control Circuit High Voltage Test Status Each parameter should display OK or Not Run.

3.	Operate the vehicle within the conditions for running the DTC to verify 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 OFF, disconnect the harness connector at the P16 instrument cluster.

2.	Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 19 X1 and ground.

3.	If the test lamp does not illuminate, 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 P16 instrument cluster.

4.	Connect a test lamp between the control circuit terminal 17 X1 and the ignition circuit terminal 19 X1.

5.	Command the MIL ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

6.	If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.

7.	If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.

8.	If all circuits test normal, replace the P16 instrument cluster.

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