Cummins ISX12 CM2250 (2010-12) Fault Code: 145 PID: 110 SPN: 110 FMI: 4 Engine Coolant Temperature 1 Sensor Circuit- Voltage Below Normal or Shorted to Low Source

Circuit Description
The coolant temperature sensor is a variable resistor sensor and is used to measure the temperature of the engine coolant. The 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 emissions control.

Component Location
The engine coolant temperature sensor is located near the thermostat housing.

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 signal voltage is less than 0.5-VDC for more than 1 second.

Action Taken When the Fault Code is Active
The ECM illuminates the amber CHECK ENGINE light and/or the Malfunction Indicator Lamp (MIL) immediately when the diagnostic runs and fails.
A default value is used for the engine coolant temperature reading.
Conditions for Clearing the Fault Code
To validate the repair, start the engine and let it idle for 1 minute.
The fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
The ECM will turn off the amber CHECK ENGINE lamp after the diagnostic runs and passes.
For ODB engines, the ECM will turn off the MIL after three consecutive trips where the diagnostic runs and passes.
The ?Reset All Faults? command in INSITE? electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD engines.

Shop Talk
The engine coolant temperature sensor shares return wires in the engine harness with other sensors. A shorted return can cause multiple fault codes to be active. Before troubleshooting Fault Code 145, check for multiple fault codes.

Possible causes of this fault code include:

Signal shorted to ground in the harness
Signal shorted to return or ground in the sensor.

Possible Cause:
1) Engine Harness
2) ECM failure