PACCAR PX-6 CM2150 (2007-09) Fault Code: 1879 PID: SID 324 SPN: 3251 FMI: 3 Aftertreatment Particulate Filter Differential Pressure Sensor Circuit – Voltage Above Normal or Shorted to High Source. High signal voltage detected at the aftertreatment differential 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, recalibrate the ECM.

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 aftertreatment diesel particulate filter differential pressure sensor.
2)Repair or replace the OEM harness.