Cummins ISB4.5 CM2150 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 0.12-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.
-Engine torque could possibly be reduced.
-A default value is used for the coolant temperature reading.

Conditions for Clearing the Fault Code
-To validate the repair, start the engine and let it idle for 1 minute.

For engines equipped with SCR aftertreatment:

-This fault code can not be cleared with INSITE™ electronic service tool.
-The ECM will turn off the amber CHECK ENGINE lamp and/or MIL immediately after the diagnostic runs and passes.
-Use INSITE™ electronic service tool to verify the fault code is inactive.
-The inactive fault code will be cleared from the memory after 9600 hours of engine operation without a reoccurrence.

For all other engines:

-The ECM will turn off the amber CHECK ENGINE lamp after the diagnostic runs and passes.
-For On-Board Diagnostics (OBD) engines, the ECM will turn off the MIL after 3 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 fault codes, as well as extinguish the MIL for OBD applications.

Shop Talk
On some engines, the 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
-Signal shorted to ground in the harness
-Signal shorted to return or ground in the sensor