PACCAR PX-8 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.

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. Reference the following procedure in the corresponding Troubleshooting and Repair Manual for the engine being serviced.

The aftertreatment sensors share a common ground wire with the coolant level sensor. Fault codes or problems related to the coolant level sensor and its ground circuit could potentially cause this fault.

Possible causes:

1)Coolant level sensor and/or coolant level sensor ground circuit fault codes or related problems
2)Stuck in-range aftertreatment diesel oxidation catalyst inlet temperature sensor
3)High resistance in the aftertreatment diesel oxidation catalyst inlet temperature sensor signal or return lines
4)A miswired OEM harness
5)A face plugged or damaged aftertreatment diesel oxidation catalyst.

Possible repairs:

1)Replace the aftertreatment diesel oxidation catalyst inlet temperature sensor.
2)Replace the aftertreatment diesel particulate filter inlet temperature sensor.
3)Repair or replace the OEM harness and/or the aftertreatment harness.
4)Clean the aftertreatment diesel oxidation catalyst.