Circuit DescriptionThe diesel exhaust fluid dosing unit returns diesel exhaust fluid to the tank through the return line. Component LocationThere are three diesel exhaust fluid lines. One line is between the dosing unit and aftertreatment nozzle, and the other two lines are between the dosing unit and diesel exhaust fluid tank. These lines can be partially hidden from view by the Selective Catalytic Reduction (SCR) system and other vehicle components. Line routing will vary, based on aftertreatment architecture and the OEM. Conditions for Running the DiagnosticsThis diagnostic runs continuously when the engine is initially started and the SCR system is...

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 that controls the flow of engine coolant to a heating coil inside the diesel exhaust 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 aftertreatment diesel exhaust fluid tank heater control valve is located near the aftertreatment diesel exhaust fluid tank. Specific location will vary, depending...

Circuit DescriptionThe aftertreatment diesel exhaust fluid return valve is controlled by the aftertreatment diesel exhaust fluid controller. The return valve position determines where afterteatment diesel exhaust fluid will flow as it exits the dosing unit. When the return valve is energized, the dosing system will purge and return the aftertreatment diesel exhaust fluid in the lines to the tank. Component LocationThe aftertreatment diesel exhaust fluid return valve is internal to the aftertreatment diesel exhaust fluid dosing unit and can not be serviced separately. Conditions for Running the DiagnosticsThis diagnostic runs continuously when the keyswitch is in the ON position. Conditions...

Circuit DescriptionThe aftertreatment diesel exhaust fluid return valve is controlled by the aftertreatment diesel exhaust fluid controller.The return valve position determines where diesel exhaust fluid will flow as it exits the dosing unit.When the return valve is activated, the dosing system will purge and return the diesel exhaust fluid in the lines to the tank. Component LocationThe aftertreatment diesel exhaust fluid return valve is internal to the aftertreatment diesel exhaust fluid dosing unit and can not be serviced separately. Conditions for Running the DiagnosticsThis diagnostic runs continuously when the keyswitch is in the ON position. Conditions for Setting the Fault...

Circuit DescriptionThe aftertreatment diesel exhaust fluid return valve is controlled by the aftertreatment diesel exhaust fluid controller. The return valve position determines where diesel exhaust fluid will flow as it exits the dosing unit. When the return valve is activated, the dosing system will purge and return the diesel exhaust fluid in the lines to the tank. Component LocationThe aftertreatment diesel exhaust fluid return valve is internal to the aftertreatment diesel exhaust fluid dosing unit and can not be serviced separately. Conditions for Running the DiagnosticsThis diagnostic runs continuously when the keyswitch is in the ON position. Conditions for Setting...