PACCAR PX-9 CM2350 (2013-17) Fault Code:3321 PID: SPN:3246 FMI:4 Aftertreatment 1 Diesel Particulate Filter Outlet Temperature Sensor Circuit – Voltage Below Normal or Shorted to Low Source

Reason:
Aftertreatment Diesel Particulate Filter Outlet Temperature Sensor Circuit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the aftertreatment diesel particulate filter outlet temperature sensor circuit.

Effect:
Possible reduced engine performance

Circuit Description:
The aftertreatment diesel particulate filter temperature sensor module is a smart device that communicates with the engine control module via the J1939 data link. The aftertreatment diesel partculate filter temperature sensor module performs its own internal diagnostics and reports malfunctions back to the engine control module using the J1939 data link. The aftertreatment diesel particulate filter temperature sensor module is used to measure the aftertreatment diesel oxidation catalyst intake temperature, aftertreatment diesel particulate filter intake temperature, and aftertreatment diesel particulate filter outlet temperature. The temperature probes are permanently attached to the aftertreatment diesel particulate filter temperature sensor module and can not be replaced individually.

Component Location:
The aftertreatment diesel particulate filter outlet temperature sensor is located in the aftertreatment system. It is located at the outlet of the aftertreatment diesel particulate filter. Refer to the original equipment manufacturer (OEM) service manual.

Conditions for Running the Diagnostics:
This diagnostic runs continuously when the keyswitch is in the ON position and the engine is running.

Conditions for Setting the Fault Codes:
The aftertreatment diesel particulate filter temperature sensor module reported the aftertreatment diesel particulate filter outlet temperature signal was out of range low.

Action Taken When the Fault Code is Active:
1) The ECM illuminates the amber CHECK ENGINE lamp and/or the Malfunction Indicator Lamp (MIL) immediately when the diagnostic runs and fails.
2) A default value for the aftertreatment diesel particulate filter outlet temperature sensor reading is used.
3) Active and stationary regeneration of the diesel particulate filter will be disabled.
4) Diesel exhaust fluid injection into the aftertreatment system is disabled.
5) Engine torque will be reduced if the engine is operated for an extended period of time with this fault active.

Conditions for Clearing the Fault Code:
1) To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
2) The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
3) The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
4) For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (MIL) after three consecutive trips where the diagnostic runs and passes.
5) The Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

Shop Talk:
Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.

For intermittent power supply and datalink communication issues with Aftertreatment Components, it is highly recommended that the OEM Power Distribution Center fuses and relays be thoroughly checked for loose, missing or intermittent connections.

Possible Causes:
1) A malfunctioning aftertreatment diesel particulate filter outlet temperature sensor