Cummins ISX11.9 CM2250 (2010-12) Fault Code: 3648 PID: SID 254 SPN: 5480 FMI: 16 Aftertreatment DEF Controller Temperature- Data Valid But Above Normal Operating Range- Moderately Severe Level

Circuit Description
The aftertreatment DEF controller is air cooled, and is equipped with an internal temperature sensor, which monitors the temperature inside the controller during opertion. The DEF controller communicates this temperature reading to the engine ECM via a J1939 data link connection.

Component Location
The aftertreatment DEF controller in equipped with an internal temperature sensor, which monitors the temperature inside the controller during operation. This temperature sensor is internal to the DEF controller and cannot be service separately.

Conditions for Running the Diagnostics
This diagnostic runs during normal operation when dosing is being commanded by the SCR system.

Conditions for Setting the Fault Codes
The internal temperature of the DEF controller is above 114?C [238?F] for more than 5 seconds.

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.
DEF 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 DEF controller internal temperature falls below the warning limits and 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
Troubleshoot high inactive counts of Fault Code 3648 as an active fault code.

Possible causes of this fault code include:

Inadequate air flow to cool DEF controller
Improper mounting of DEF controller
Malfunctioning DEF controller.
Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the original equipment manufacturer (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 Cause:
1) ECM calibration