Circuit DescriptionThe aftertreatment diesel exhaust fluid dosing unit heater is used to defrost and/or prevent freezing of the diesel exhaust fluid dosing unit.

Component LocationThe aftertreatment diesel exhaust fluid dosing unit location is original equipment manufacturer (OEM) dependent. Refer to the OEM service manual.

Conditions for Running the DiagnosticsThe engine must be turned OFF for period of 8 hours before this diagnostic will run. This diagnostic runs when the keyswitch is turned to the ON position after an 8 hour cold soak.

Conditions for Setting the Fault CodesThe Engine Control Module (ECM) detected the aftertreatment diesel exhaust fluid dosing unit heater temperature reading was higher or lower than the other temperature sensors on the engine after an extended period of engine OFF time.

Action Taken When the Fault Code is ActiveThe ECM illuminates the amber CHECK ENGINE lamp and/or Malfunction Indicator Lamp (MIL) after the diagnostic fails on two consecutive trips.

Conditions for Clearing the Fault CodeIf the fault code does not go inactive, it may be necessary to perform a 8 hour cold soak with the key OFF, then turn the keyswitch to the ON position so that the key ON portion of the diagnostic will run.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 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:

A malfunctioning aftertreatment diesel exhaust fluid dosing unit heater temperature sensor

Possible Cause:1) OEM harness2) ECM calibration