SPN 110 - FMI 4 (Fault Code 145)

Engine Coolant Temperature 1 Sensor Circuit - Voltage Below Normal or Shorted to Low Source

Engine Coolant Temperature Sensor Circuit

Fault Code: 145
PID(P), SID(S): P110
SPN: 110
FMI: 4/4
Lamp: Amber

REASON: Low signal voltage detected at engine coolant temperature circuit.

EFFECT: Fan will stay ON if controlled by the engine control module (ECM).

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

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

Conditions for Running the Diagnostics:
This diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected the engine coolant temperature signal voltage was out of range low.

Action Taken When the Fault Code is Active:
• The ECM illuminates the amber CHECK ENGINE lamp 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, perform a key cycle, start the engine and let it idle for 1 minute.
• The fault code status displayed by the recommended Cummins® electronic service tool or equivalent will change to INACTIVE immediately after the diagnostic runs and passes.
• The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
• The "Reset All Faults" command in the recommended Cummins® electronic service tool or equivalent can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

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.
• Malfunctioning engine coolant temperature sensor.

Read More:
SPN 91 - FMI 0 (Fault Code 148)
SPN 91 - FMI 1 (Fault Code 147)


Subscribe to receive free email updates:

0 Response to "SPN 110 - FMI 4 (Fault Code 145)"

Post a Comment