Circuit DescriptionThe aftertreatment diesel exhaust fluid controller is the central control for the selective catalytic reduction (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 the electronic control module (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 suitable rigid bracket using three or four capscrews. Refer to the OEM service manual for a more detailed component location description.

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

Conditions for Setting the Fault CodesAn internal error has been detected in the aftertreatment diesel exhaust fluid controller, and has been communicated to the ECM via the data link.

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.Diesel exhaust fluid 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 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.For On Board Diagnostic (OBD) engines, the ECM will turn off the MIL after 3 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 TalkThe aftertreatment diesel exhaust fluid controller is not serviceable, and must be replaced when malfunctioning.

Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the 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