PACCAR PX-9 CM2350 (2013-17) Fault Code:3231 PID: SPN:4360 FMI:0 Aftertreatment SCR Intake Temperature – Data Valid But Above Normal Operating Range – Moderately Severe Level

Reason:
Aftertreatment SCR Intake Temperature – Data Valid But Above Normal Operating Range – Moderately Severe Level. The SCR intake temperature sensor reading has exceeded the maximum temperature limit.

Effect:
Progressive power and/or speed derate increasing in severity from time of alert. If the Engine Protection Shutdown feature is enabled, the engine will shut down 30 seconds after the red STOP lamps starts flashing.

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 intake 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 by the OEM near the aftertreatment SCR catalyst.

Conditions for Running the Diagnostics:
This diagnostic runs continuously when the engine is running and active SCR system cleaning of the aftertreatment is not occurring

Conditions for Setting the Fault Codes:
The aftertreatment SCR temperature sensor module reported the aftertreatment SCR intake temperature signal was out of range high.

Action Taken When the Fault Code is Active:
1) The ECM illuminates the red STOP ENGINE lamp immediately after the diagnostic runs and fails.
2) The engine will be shut down if the Engine Protection Shutdown feature is enabled.

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 red STOP ENGINE lamp immediately after the diagnostic runs and passes.
4) The Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults.

Shop Talk:
N/A

Possible Causes:
1) Malfunctioning fuel injectors
2) Contaminated diesel exhaust fluid