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 Descriptors
DTC P0655: Engine Coolant Temperature Lamp Control CircuitDTC P0655 01: Engine Coolant Temperature Lamp Control Circuit Short to Battery
DTC P0655 02: Engine Coolant Temperature Lamp Control Circuit Short to Ground
DTC P0655 04: Engine Coolant Temperature Lamp Control Circuit Open Circuit
DTC P0655 54: Engine Coolant Temperature Lamp Control Circuit Temperature High
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Voltage Supply | P0655, P0655 02 | P0655, P0655 04 | -- | -- |
Control Circuit | P0655, P0655 02 | P0655, P0655 04 | P0655, P0655 01 | P0655 54 |
Circuit/System Description
The engine coolant temperature lamp is located on the instrument panel cluster (IPC). The lamp informs the driver if an engine over heat condition has occurred and that the engine cooling system requires service. The engine control module (ECM) monitors the lamp control circuit for conditions that are incorrect for the commanded state of the lamp. For example, a failure condition exists if the ECM detects low voltage when the lamp is commanded OFF, or high voltage when the lamp is commanded ON.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | The ignition voltage is between 8.5-16.5 volts. |
| • | DTC P0655 runs continuously once the above conditions are met. |
Conditions for Setting the DTC
P0655 01
The ECM detects a short to voltage on the circuit that controls the lamp.
P0655 02
The ECM detects a short to ground on the circuit that controls the lamp.
P0655 04
The ECM detects an open on the circuit that controls the lamp.
P0655 54
The ECM detects that the internal output driver is over temperature.
Action Taken When the DTC Sets
DTC P0655 is a Type C DTC.
Conditions for Clearing the DTC
DTC P0655 is a Type C DTC.
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
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, command the lamp ON and OFF with a scan tool. The lamp should turn ON and OFF as commanded.
Circuit/System Testing
- If any other IPC indicators or gages are inoperative, refer to Symptoms - Displays and Gages.
- Ignition OFF, disconnect the ECM harness connectors. Ignition ON, the lamp should not illuminate.
- Ignition ON, connect a 3A fused jumper wire between the lamp control circuit and ground. The lamp should illuminate.
- If all circuits test normal, replace the ECM.
| ⇒ | If the lamp is illuminated, test the lamp control circuit for a short to ground. If the circuit tests normal, replace the IPC. |
| ⇒ | If the lamp does not illuminate, test the lamp control circuit for a short to voltage, or an open/high resistance. If the circuit tests normal, replace the IPC/bulb. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for engine control module replacement, setup, and programming |
