Cummins ISX12 CM2250 (2010-12) Fault Code: 3148 PID: SPN: 4363 FMI: 2 Aftertreatment SCR Outlet Temperature Sensor- Data Erratic, Intermittent, or Incorrect

Circuit Description
The SCR outlet temperature sensor is used by the engine control module (ECM) to monitor the engine exhaust temperature exiting the SCR catalyst. The ECM monitors the voltage on the signal pin and converts this to a temperature value.

Component Location
The SCR outlet temperature sensor is located in the aftertreatment system. The sensor is located after the 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
This fault code is logged if the value of the SCR catalyst outlet temperature sensor does not match the engine operating conditions for more than 5 minutes.

Action Taken When the Fault Code is Active
The ECM illuminates the amber CHECK ENGINE lamp and/or the malfunction indicator lamp (MIL) immediately when the diagnostic runs and fails for two consecutive trips.
A default value for the SCR catalyst outlet temperature is used.
Diesel exhaust fluid injection into the aftertreatment system is disabled.
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
To validate the repair using a Diagnostic Road Test, utilize a route that incorporates both stop-and-go city driving and steady state highway driving. It may be necessary to load the unit for certain diagnostics in the ECM to run.
To validate the repair using a Chassis Dynamometer Test, utilize a routine that incorporates acceleration and motoring events, steady state highway operation, and load. This will simulate normal driving and allow the diagnostics in the ECM to run.
The fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
The ECM will turn off the amber CHECK ENGINE lamp after the diagnostic runs and passes.
For On-Board Diagnostic (OBD) engines, the ECM will turn off the MIL after three consecutive trips where the diagnostic runs and passes.
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
Possible causes of this fault code include:

Stuck in-range SCR outlet temperature sensor
High resistance in the SCR outlet temperature sensor signal or return lines.
Malfunctioning aftertreatment SCR catalyst temperature sensor interface module.
Reference the appropriate original equipment manufacturer (OEM) wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.

For intermittent power supply and data link 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 Cause:
1) Aftertreatment SCR catalyst temperature sensor Interface module failure
2) ECM failure
3) OEM harness, Engine Harness, 14-pin crossover connector failure