Circuit DescriptionThe Engine Control Module (ECM) provides a 5 volt supply and a ground to the aftertreatment diesel exhaust fluid pressure sensor. The pressure sensor provides a signal to the ECM on the sensor signal circuit. This sensor signal voltage changes, based on the aftertreatment diesel exhaust fluid pressure supplied by the dosing unit. The ECM will detect a low signal voltage at low diesel exhaust fluid pressures, and a high signal voltage at high diesel exhaust fluid pressures.

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 when the diesel exhaust fluid dosing unit is in the priming or dosing state.

Conditions for Setting the Fault CodesThe Engine Control Module (ECM) detected the aftertreatment diesel exhaust fluid pressure was less than a threshold.

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 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 the “Aftertreatment Diesel Exhaust Fluid Doser Pump Override Test” found under “ECM Diagnostic Tests” in the INSITE™ electronic service toolThe 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 TalkTroubleshoot other active SCR related faults before this fault.

Possible causes of this fault code include:

Low diesel exhaust fluid tank levelBlocked, restricted, or frozen diesel exhaust fluid dosing unit supply lineBlocked or restricted diesel exhaust fluid tank filterBlocked or restricted diesel exhaust fluid dosing unit filterBlocked or restricted diesel exhaust fluid dosing unit supply line fittingMalfunctioning diesel exhaust fluid dosing unitContaminated diesel exhaust fluidDebris from the diesel exhaust fluid tank. If debris is found in the diesel exhaust fluid tank, clean the diesel exhaust fluid tank thoroughly and fill with certified diesel exhaust fluid.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) DEF tank filter failure2) Aftertreatment DEF dosing unit intake fitting failure3) DEF tank vent filter, DEF suction line failure4) ECM calibration