Circuit DescriptionThe aftertreatment fuel pressure sensor is used to monitor the fuel pressure into the aftertreatment system. The engine control module (ECM) supplies the aftertreatment fuel pressure sensor a 5 volt reference voltage. When the fuel pressure is low, the sensor signal voltage is low. When the fuel pressure is high, the sensor signal voltage is near the 5 volt reference voltage. The ECM monitors the aftertreatment fuel pressure signal circuit voltage to calculate the pressure of the fuel within the aftertreatment system.

Component LocationThe aftertreatment fuel injector is installed in the exhaust system in the turbocharger adapter pipe. The aftertreatment fuel pressure sensor and aftertreatment fuel shutoff valve are installed in the shutoff valve manifold. The aftertreatment purge air actuator is located above the shutoff valve manifold.

Conditions for Running the DiagnosticsThis diagnostic runs during active regeneration of the aftertreatment diesel particulate filter.

Conditions for Setting the Fault CodesThe aftertreatment fuel pressure was less than 300 kPa [43.5 psi] for more than 15 seconds.

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.Active regeneration of the aftertreatment diesel particulate filter will be disabled unitl the next key cycle.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, start the engine and perform the INSITE™ electronic service tool Aftertreatment Diesel Particulate Filter Regeneration Test.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:

Plugged or restricted aftertreatment fuel supply linePlugged or restricted aftertreatment fuel shutoff manifoldPlugged or restricted pressure side fuel filterMalfunctioning fuel pump gear pump.

Possible Cause:1) Fuel filter failure2) Gear pump failure3) ECM calibration