Circuit DescriptionThe aftertreatment fuel pressure sensor is used to monitor the fuel pressure into the aftertreatment system. The electronic 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 pressure sensor is located in the aftertreatment shutoff valve assembly.

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

Conditions for Setting the Fault CodesThe ECM detects that the aftertreatment fuel pressure signal voltage is less than 0.2-VDC for more than 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 failsActive 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 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:

Open signal circuit in the engine harness, connector, sensorSignal wire shorted to groundA shorted sensor.

Possible Cause:1) ECM failure2) Engine Harness failure3) ECM calibration