PACCAR PX-9 CM2350 (2013-17) Fault Code:3148 PID: SPN:4363 FMI:2 Aftertreatment 1 SCR Outlet Temperature Sensor – Data Erratic, Intermittent, or Incorrect

Reason:
Aftertreatment SCR Outlet Temperature Sensor – Data Erratic, Intermittent, or Incorrect. The SCR outlet temperature sensor is not changing with engine operating conditions.

Effect:
Possible reduced engine performance

Circuit Description:
The aftertreatment SCR (selective catalytic reduction) temperature sensor module is a smart device that communicates with the engine control module via the J1939 data link. The aftertreatment SCR temperature sensor module performs its own internal diagnostics and reports malfunctions back to the engine control module using the J1939 data link. The aftertreatment SCR temperature sensor module is used to measure the aftertreatment SCR intermediate temperature and aftertreatment SCR outlet temperature. The temperature probes are permanently attached to the aftertreatment SCR temperature sensor module and can not be replaced individually.

Component Location:
The aftertreatment SCR temperature sensor module is mounted on the aftertreatment SCR catalyst.

Conditions for Running the Diagnostics:
This diagnostic runs when the exhaust gas temperature sensors are compared to other engine temperatures during engine operation. The engine coolant temperature must be above 60°C [140°F] before the diagnostic will run.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected the aftertreatment SCR outlet temperature sensor signal was irrational for more than 5 minutes.

Action Taken When the Fault Code is Active:
1) The ECM illuminates the amber CHECK ENGINE lamp and/or Malfunction Indicator Lamp (MIL) after the diagnostic fails on two consecutive trips.
2) A default value for the SCR catalyst outlet temperature is used.
3) Diesel exhaust fluid injection into the aftertreatment system is disabled.
4) 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, start the engine and let it idle for up to 5 minutes.
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 SCR outlet temperature sensor