Circuit DescriptionThe aftertreatment diesel exhaust fluid dosing valve is controlled by the ECM. When the engine control module (ECM) commands DEF dosing, the ECM sends a pulse width modulated (PWM) signal to the dosing valve, which opens the dosing valve and allows DEF to be sprayed into the exhaust stream.

Component LocationThe aftertreatment diesel exhaust fluid dosing valve is installed in the exhaust system. It is mounted directly to the aftertreatment decomposition tube, before the selective catalytic reduction (SCR) catalyst. Installation position will vary, based on the aftertreatment architecture and the original equipment manufacturer (OEM).

Conditions for Running the DiagnosticsThis diagnostic runs when the diesel exhaust fluid dosing valve is being commanded on.

Conditions for Setting the Fault CodesThe Engine Control Module (ECM) detected the aftertreatment diesel exhaust fluid dosing valve circuit was shorted high, shorted low, or open.

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.Engine torque will be severely reduced.Vehicle speed will be limited to 8 km [5 mi] per hour after extended engine operation with the fault code active.

Conditions for Clearing the Fault CodeTo validate the repair:

Perform a key cycle.Start and idle the engine.Monitor the Aftertreatment Diesel Exhaust Fluid Dosing Unit State in INSITE™ electronic service tool.The Aftertreatment Diesel Exhaust Fluid Dosing Unit State in INSITE™ electronic service tool must transition to Dosing, indicating the system has primed.Turn the key switch OFF and allow the ECM to completely powerdown.Turn the key switch ON.The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.For On-Board Diagnostics (OBD) engines, the ECM will extinguish the Malfunction Indicator Lamp (MIL) after three 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 TalkPossible causes of this fault code include:

Open circuit in the diesel exhaust fluid dosing valveA short circuit to battery in the OEM harnessA short circuit to ground in the OEM harnessAn open circuit in the OEM harnessReference 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) Aftertreatment DEF dosing valve failure2) OEM harness3) ECM calibration