Cummins ISX15 CM2250 (2010-12) Fault Code: 3231 PID: SPN: 4360 FMI: 16 Aftertreatment SCR Intake Temperature- Data Valid But Above Normal Operating Range- Moderately Severe Level

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

Component Location
The SCR intake temperature sensor is located in the aftertreatment system. The sensor is located between the aftertreatment diesel particulate filter (DPF) and the SCR catalyst in the exhaust system.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the engine is running and active regeneration of the aftertreatment DPF is not occurring.

Conditions for Setting the Fault Codes
The ECM detects that the temperature at the SCR catalyst intake temperature sensor is greater than 650?C [1202?F] for more than 60 seconds.

Action Taken When the Fault Code is Active
The ECM illuminates the red STOP ENGINE lamp immediately when the diagnostic runs and fails.
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, start the engine and let it idle for 1 minute.
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 red STOP ENGINE lamp after the diagnostic runs and passes.
The “Reset All Faults” command in INSITE? electronic service tool can be used to clear active and inactive faults.

Shop Talk
This fault will go inactive immediately after the SCR intake temperature drops below the warning limit, and will likely be inactive when the vehicle is in the shop. For these reasons, this troubleshooting tree must be used for both active and inactive fault codes.

Possible causes of this fault code include:

Degraded, diluted, or incorrect diesel exhaust fluid
Malfunctioning in-range SCR intake temperature sensor
Upstream exhaust system malfunction.
Reference the appropriate 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) ECM calibration