DTC P0650. Cadillac CTS 2009

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 2009 🢒 CTS 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC P0650

DTC P0650 without LLT

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

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 greater than 80 RPM.

•	The ignition voltage is between 10-18 volts.

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

•	DTC P0650 runs continuously once 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

Ignition ON, observe the scan tool MIL Circuit Test Status parameters. Each of the MIL circuit test status parameters should display OK or Not Run.
Ignition ON, command the MIL ON and OFF with a scan tool. The MIL should turn ON and OFF as commanded.
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

If any other IPC indicators or gages are inoperative, refer to Instrument Cluster Gages Inoperative.
Ignition OFF, disconnect the ECM harness connectors. Ignition ON, the MIL should not illuminate.

⇒	If the MIL is illuminated, test the MIL control circuit terminal 12-X2 for a short to ground. If the circuit tests normal, replace the IPC.

Ignition ON, connect a 3 A fused jumper wire between the MIL control circuit terminal 12-X2 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 test normal, replace the IPC/bulb.

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 engine control module replacement, setup, and programming

DTC P0650 with LLT