Circuit DescriptionThe selective catalytic reduction (SCR) intake temperature sensor is used by the engine control module (ECM) to monitor the engine exhaust temperature entering the SCR catalyst. The ECM monitors the voltage on the signal pin and converts this to a temperature value.

Component LocationThe SCR intake temperature sensor is located in the aftertreatment system. It is located between the diesel particulate filter and the SCR catalyst in the exhaust system.

Conditions for Running the DiagnosticsThis 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 CodesThis fault code is logged if the value of the SCR intake temperature sensor does not match the engine operating conditions for more than 5 minutes.

Action Taken When the Fault Code is ActiveThe 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 intake 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 CodeTo 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 Diagnostics (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 TalkPossible causes of this fault code include:

Stuck in-range SCR intake temperature sensorHigh resistance in the SCR intake temperature sensor signal or return linesMalfunctioning 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 failure2) ECM failure3) Engine Harness, OEM Harness, or 14-pin crossover Connector failure