Engine Coolant Temperature – Data Valid but Above Normal Operational Range – Most Severe Level
|Fault Code: 151
Engine Coolant Temperature – Data Valid but Above Normal Operational Range – Most Severe Level. Engine coolant temperature signal indicates engine coolant temperature above engine protection critical limit.
Progressive power derate increasing in severity from time of alert. If Engine Protection Shutdown feature is enabled, engine will shut down 30 seconds after red STOP lamp starts flashing.
ISX – Coolant Temperature Sensor Circuit
ISM – Coolant Temperature Sensor Circuit
The coolant temperature sensor is a variable resistor sensor and is used to measure the temperature of the coolant of the engine. The Electronic Control Module (ECM) supplies 5 volts to the coolant temperature 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. This fault code indicates that the engine coolant temperature has exceeded the engine protection limit.
The engine coolant temperature sensor is located on the thermostat housing. Use the following procedure for a detailed component location view.Refer to Procedure 100-002 in Section E.
Conditions for Running the Diagnostics
This diagnostic runs continuously when the keyswitch is in the ON position.
Conditions for Setting the Fault Codes
The ECM detects that the coolant temperature is greater than a calibratible value for 5 seconds.
Action Taken When the Fault Code is Active
- The ECM illuminates the red STOP ENGINE light immediately when the diagnostic runs and fails.
- The torque output of the engine will be reduced.
- Maximum engine operating speed will be decreased.
- The engine will be shut off if the Engine Protection Shutdown feature is enabled.
Conditions for Clearing the Fault Code
The ECM will turn off the red STOP ENGINE light immediately after the coolant temperature decreases below the engine protection limit.
Verify the ECM calibration is correct. Check the calibration revision history found on QuickServe™ Online for applicable fixes to the calibration stored in the ECM. If necessary, calibrate the ECM again. Refer to Procedure 019-032 in Section 19.
This fault code indicates that coolant temperature has exceeded the engine protection limits for high coolant temperature. It is highly unlikely that the coolant temperature sensor are failed unless there are other active coolant temperature sensor faults.
Refer to the Engine Coolant Temperature Above Normal symptom troubleshooting tree.
- For ISM engines, refer to the ISM, ISMe, and QSM11 Service Manual, Bulletin 3666322.
- For ISX engines, refer to the Signature™, ISX, and QSX15 Service Manual, Bulletin 3666239.