Circuit DescriptionThe aftertreatment diesel exhaust fluid line heater relay provides the power supply to line heaters 1, 2, and 3. It is controlled by the aftertreatment diesel exhaust fluid controller.
Component LocationThe aftertreatment diesel exhaust fluid line heater relay location is original equipment manufacturer (OEM) dependent. 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 CodesThe aftertreatment diesel exhaust fluid controller detects that the voltage in the diesel exhaust fluid line heater relay circuit is above a calibratible value.
Action Taken When the Fault Code is ActiveThe electronic control module (ECM) illuminates the amber CHECK ENGINE lamp and/or the MIL immediately when the diagnostic runs and fails.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, perform a key cycle, start the engine and let it idle for 1 minute.The fault code status displayed by the 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 immediately after the diagnostic runs and passes.For 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 the 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:
Short to battery voltage in the diesel exhaust fluid line heater relay circuitShort to battery voltage in the 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) Aftertreatment DEF Controller harness failure2) ECM calibration