Circuit DescriptionThe aftertreatment diesel exhaust fluid controller provides a 5 volt supply and a ground to the aftertreatment diesel exhaust fluid pressure sensor. The pressure sensor provides a signal to the aftertreatment diesel exhaust fluid controller on the sensor signal circuit. This sensor signal voltage changes based on the aftertreatment diesel exhaust fluid pressure supplied by the dosing unit. The aftertreatment diesel exhaust fluid controller will detect a low signal voltage at low aftertreatment diesel exhaust fluid pressures, and high signal voltage at high aftertreatment diesel exhaust fluid pressures. The aftertreatment diesel exhaust fluid pressure sensor reading is communicated to the engine control module (ECM) via the engine data link.

Component LocationThe aftertreatment diesel exhaust fluid pressure sensor is internal to the aftertreatment diesel exhaust fluid dosing unit and can not be serviced separately.

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

Conditions for Setting the Fault CodesThe diesel exhaust fluid controller detects that the diesel exhaust fluid pressure sensor signal voltage is less than 0.25-VDC for 1 second.

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, perform a key cycle, and then 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 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:

SIGNAL wire shorted to groundMalfunctioning aftertreatment diesel exhaust fluid controllerMalfunctioning aftertreatment diesel exhaust fluid controller harness.Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.

For intermittent power supply and data link 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 failure2) Aftertreatment DEF controller harness failure3) ECM calibration