P0217

P0217-COOLANT TEMPERATURE TOO HIGH





For a complete wiring diagram, refer to the Wiring Information Electrical Diagrams. Electrical Diagrams

Theory of Operation

The Coolant Temperature Sensor is a variable resistor sensor and is used to measure the temperature of the coolant of the engine. The ECM supplies 5-volts to the Coolant Temperature Sensor Signal circuit. The ECM monitors the change in voltage caused by changes in the resistance of the sensor to determine the coolant temperature. The engine coolant temperature value is used by the ECM for the engine protection system and engine emissions control. The engine Coolant Temperature Sensor is located near the thermostat housing. This fault becomes active when the ECM detects a coolant temperature higher than a calibratable limit for a calibratable amount of time. The ECM illuminates the MIL lamp after the diagnostic runs and fails once. During this time the customer may experience an engine power derate, and regeneration mode will be disabled. The ECM will turn off the MIL lamp after the diagnostic runs and passes in 4 consecutive drive cycles.

- When Monitored:
While the engine is running.

- Set Condition:
The engine coolant temperature is above a calibrated value for a calibrated amount of time.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. COOLING SYSTEM FAILURE

NOTE: If other cooling system DTCs are present, repair those DTCs before proceeding.

1. Check the engine cooling system operation. Refer to cooling, Diagnosis and Testing, Preliminary check. Testing and Inspection.

Is the Cooling system operating normally?

Yes

- Go To 2

No

- Repair the cooling system failure.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

2. ECT SENSOR
1. Allow the engine to reach normal operating temperature.
2. Use a temperature probe and measure the engine temperature near the ECT Sensor.
3. With the scan tool, read the Engine Temperature.
4. Compare the temperature probe reading with the scan tool reading.

Are the readings within 10°F of each other?

Yes

- Repair the cause of mechanical failure.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Replace the Coolant Temperature Sensor.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.