PACCAR PX-6 CM2150 (2007-09) Fault Code: 451 PID: 157 SPN: 157 FMI: 3 Injector Metering Rail Number 1 Pressure Sensor Circuit – Voltage Above Normal or Shorted to High Source. High signal voltage detected at rail fuel pressure sensor circuit.

Verify the electronic control module (ECM) calibration is correct. Check the calibration revision history found on QuickServe™ Online for applicable fixes to the calibration stored in the ECM. If necessary, calibrate the ECM.

This fault code will become active if there is an open circuit on any of the three pins (+5 volt supply, signal, or return) that connect the sensor or ECM to the wiring harness. This fault will also be active if the signal wire is shorted to a source of voltage. This fault code will become inactive any time the keyswitch is ON and the signal returns to a valid in-range voltage.

Possible causes:

1)Voltage (+5-VDC or higher shorted to the signal wire)
2)Open circuit on the signal wire
3)Open circuit on the +5 volt supply wire
4)Open circuit on the return wire
5)Damaged sensor
6)Damaged ECM.

Possible repairs:

1)Repair or replace the damaged harness, connector, or pins.
2)Replace the rail fuel pressure sensor.
3)The removal and installation of the connector may correct the fault.
4)Replace the engine harness.
5))Replace the ECM