Cummins ISB CM850 (2003-06) Fault Code: 298 PID: 223 SPN: 1388 FMI: 4 Auxiliary Pressure Sensor Input 1 Circuit – Voltage Above Normal, or Shorted to High Source. High signal voltage detected at the OEM pressure circuit.

Cummins ISB CM850 (2003-06) Fault Code: 298 PID: 223 SPN: 1388 FMI: 4 Auxiliary Pressure Sensor Input 1 Circuit – Voltage Above Normal, or Shorted to High Source. High signal voltage detected at the OEM pressure circuit.

Possible causes:

1)Open return circuit in the harness, connectors, or sensor.
2)signal circuit shorted to sensor supply or battery voltage.

Possible repairs:

1)Replace the OEM pressure sensor.
2)Replace the ECM.