Cummins ISM CM875 (2003-06) Fault Code: 263 PID: P174 SPN: 174 FMI: 3/3 Engine Fuel Temperature Sensor Circuit – Voltage Above Normal or Shorted to High Source. High signal voltage detected at engine fuel temperature circuit.

Beginning with ESN 14039654, the temperature sensor return circuit was separated from the pressure sensor return circuit. For ESNs prior to this and with engine wiring harness Part Number 3682854, refer to the Common Pressure/Temperature Sensor Return Circuit above. For this ESN and greater or for any other engine wiring harness part number, refer to the Separate Pressure/Temperature Sensor Return Circuit above.

The engine fuel temperature sensor shares return wires in the engine harness with other sensors. An open return can cause multiple fault codes to be active. Before troubleshooting Fault Code 263, check for multiple fault codes.

Possible causes:

1)Open return circuit in the harness, connectors, sensor, or ECM
2)Open signal circuit or shorted to a voltage source.

Possible repairs:

1)Replace the engine fuel temperature sensor.
2)Replace the ECM.
3)Repair or replace the engine harness.