Circuit DescriptionThe 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 LocationThe 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 DiagnosticsThis diagnostic runs continuously when the engine is running.

Conditions for Setting the Fault CodesThe 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 ActiveThe 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 CodeTo 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 toolThis 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 TalkPossible caused of this fault code include:

Malfunctioning aftertreatment diesel exhaust fluid tank heater control valveAn open circuit in the harnessA short circuit to battery in the harness.

Possible Cause:1) ECM calibration