Cummins ISM CM870 (2003-06) Fault Code: 546 PID: P094 SPN: 94 FMI: 3/3 Rail Fuel Pressure Sensor Circuit – shorted high. High signal voltage detected at the rail fuel pressure circuit.

The rail fuel pressure sensor shares supply and return wires in the engine harness with other sensors. Opens and shorts in the engine harness can cause multiple fault codes to be active. Before troubleshooting fault code 546, check for multiple faults.

Possible causes:

1)Open return circuit in the engine harness, connectors, or sensor.
2)Signal circuit shorted to sensor supply or battery voltage.
3)Sensor supply circuit shorted to battery voltage.

Possible repairs:

1)Replace the rail fuel pressure sensor.
2)ir or replace the engine harness.
3)Replace the ECM.