PACCAR PX-6 CM2150 (2007-09) Fault Code: 1878 PID: SPN: 3245 FMI: 2 Aftertreatment Exhaust Gas Temperature 3 – Data Erratic, Intermittent, or Incorrect. The aftertreatment diesel particulate filter outlet temperature sensor is not changing with engine operating conditions.

Verify the 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.

Possible causes:

1)Stuck in-range aftertreatment diesel particulate filter outlet temperature sensor
2)High resistance in the aftertreatment diesel particulate filter outlet temperature sensor signal or return wires.

Possible repairs:

1)If no short is found, replace the temperature sensor that is reading higher or lower than the other sensors.
2)Replace the aftertreatment diesel particulate filter outlet temperature sensor.
3)Replace the OEM harness.
4)Replace the aftertreatment harness.
5)Replace all interconnects.
6)Replace the ECM.