Circuit DescriptionThe aftertreatment diesel exhaust fluid controller is the central control for the SCR diesel exhaust fluid dosing system, and handles the dosing activity, tank level sensing, tank temperature sensing, line heating, and tank heating. It communicates to the engine via ECM via a J1939 data link connection.

Component LocationThe location of the aftertreatment diesel exhaust fluid controller varies by application and OEM. The controller will typically be mounted to the vehicle frame or a suitable rigid bracket using 3 or 4 capscrews. Refer to the OEM service manual.

Conditions for Running the DiagnosticsThis diagnostic runs continuously when the keyswitch is in the ON position.

Conditions for Setting the Fault CodesAn unexpected data link message was sent from the ECM to the diesel exhaust fluid controller, and was unable to be interpreted.

Action Taken When the Fault Code is ActiveThe ECM illuminates the amber CHECK ENGINE light immediately when the diagnostic runs and fails.Diesel exhaust fluid injection into the aftertreatment system is disabled.Conditions for Clearing the Fault CodeTo 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 amber CHECK 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 TalkPossible causes of this fault code include:

Incorrect data link termination resistanceOpen or short circuit on J1939 data linkMalfunctioning engine ECMCorrupted engine calibrationMalfunctioning diesel exhaust fluid controllerCorrupted diesel exhaust fluid controller calibration

Possible Cause:1) ECM failure2) Aftertreatment DEF controller failure