Cummins ISX12 CM2250 (2010-12) Fault Code: 5278 PID: SPN: 6802 FMI: 31 Aftertreatment 1 Diesel Exhaust Fluid Dosing System Frozen- Condition Exists

Circuit Description
The aftertreatment diesel exhaust fluid tank heater keeps the diesel exhaust fluid from freezing in the diesel exhaust fluid tank. The tank heater consists of an electrically powered tank heater control valve which controls the flow of engine coolant to a heating coil inside the diesel exhaust fluid tank. The tank heater control valve opens to allow coolant to flow to the heating coil when heating is commanded, and closes when heating is no longer required.

Component Location
The diesel exhaust fluid tank heater control valve is located near the diesel exhaust fluid tank. Specific location will vary depending on the OEM. The tank heating coil is internal to the diesel exhaust fluid tank.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the engine is running.

Conditions for Setting the Fault Codes
The Engine Control Module (ECM) detected the diesel exhaust fluid dosing system was unable to prime when the ambient air temperature was low (non-heated diesel exhaust fluid dosing systems).

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.
The torque output of the engine will be reduced.
Conditions for Clearing the Fault Code
To validate the repair, perform a key cycle, and then use INSITE? electronic service tool to perform the Diesel Exhaust Fluid Doser System Heater Test found under ECM Diagnostic Tests.
To validate the repair, perform the “Aftertreatment Diesel Exhaust Fluid Doser Pump Override Test” found under “ECM Diagnostic Tests” in the INSITE? electronic service tool
This fault code can not be cleared with INSITE? electronic service tool.
The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
The inactive fault code will be cleared from the memory after 9600 hours of engine operation without a reoccurrence.

Shop Talk
Possible caused of this fault code include:

Malfunctioning aftertreatment diesel exhaust fluid tank heater control valve
An open circuit in the harness
A short circuit to battery in the harness.

Possible Cause:
1) ECM calibration