Circuit DescriptionThe aftertreatment diesel exhaust fluid line heater 2 is controlled by the aftertreatment diesel exhaust fluid controller, and receives power through the switch side of the diesel exhaust fluid line heater relay.

Component LocationThe aftertreatment diesel exhaust fluid line heater 2 is located on the return line between the diesel exhaust fluid dosing unit and diesel exhaust fluid tank.

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

Conditions for Setting the Fault CodesThe aftertreatment diesel exhaust fluid controller detects that the line heater circuit is open or shorted to ground.

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.Engine torque will be reduced if the engine is operated for a limited period of time with the fault code active.Engine torque will be severely reduced and 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, and then use INSITE? electronic service tool to perform the Diesel Exhaust Fluid Doser System Heater Test found under ECM Diagnostic Tests.The fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately after all three line heaters are commanded on and 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 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 include:

Malfunctioning line heater relayMalfunctioning line heaterOpen circuit, short circuit to ground, or a blown fuse in the aftertreatment diesel exhaust fluid controller harnessMalfunctioning aftertreatment diesel exhaust fluid controller.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