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.
The catalyst inlet temperature sensor shares return wires in the OEM harness with other sensors. A shorted return can cause multiple fault codes to be active.
Possible causes:
1)Open return circuit in the harness, connectors, or sensor
2)Open signal circuit or shorted to a voltage source.
Possible repairs:
1)Replace the aftertreatment diesel particulate filter inlet temperature sensor.
2)The removal and installation of the connector may correct the fault.
3)Replace the OEM harness, aftertreatment harness, and all interconnects.
4)Replace the ECM.
PACCAR PX-6 CM2150 (2007-09) Fault Code: 1674 PID: SPN: 3249 FMI: 4 Aftertreatment Exhaust Gas Temperature 2 Circuit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the aftertreatment diesel particulate filter inlet temperature sensor circuit.
PACCAR PX-6 CM2150 (2007-09) Fault Code: 1667 PID: SPN: 3241 FMI: 2 Aftertreatment Exhaust Gas Temperature 1 – Data Erratic, Intermittent, or Incorrect. The aftertreatment diesel oxidation catalyst inlet temperature sensor is not changing with engine operating conditions.
PACCAR PX-6 CM2150 (2007-09) Fault Code: 1666 PID: SPN: 3241 FMI: 3 Aftertreatment Exhaust Gas Temperature 1 Circuit – Voltage Above Normal or Shorted to High Source. High signal voltage detected at the catalyst inlet temperature sensor circuit.
PACCAR PX-6 CM2150 (2007-09) Fault Code: 1665 PID: SPN: 3241 FMI: 4 Aftertreatment Exhaust Gas Temperature 1 Circuit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the catalyst inlet sensor circuit.
PACCAR PX-6 CM2150 (2007-09) Fault Code: 1664 PID: SPN: 3050 FMI: 11 Catalyst Missing – Condition Exists. The aftertreatment catalyst in the exhaust system is not present.
PACCAR PX-6 CM2150 (2007-09) Fault Code: 1663 PID: SPN: 3241 FMI: 11 Catalyst Inlet Temperature Sensor Swapped with Outlet – Condition Exists. The inlet and outlet catalyst temperature sensor connections are swapped.