PACCAR PX-9 CM2350 (2013-17) Fault Code:1923 PID:SID 334 SPN:3482 FMI:3 Aftertreatment Fuel Shutoff Valve Circuit – Voltage Above Normal or Shorted to High Source

Reason:
Aftertreatment Fuel Shutoff Valve 1 Circuit – Voltage Above Normal, or Shorted to High Source. High signal voltage detected at the aftertreatment fuel shutoff valve circuit.

Effect:
Possible reduced engine performance

Circuit Description:
The aftertreatment fuel shutoff valve is used to disable the fuel supply to the aftertreatment system.

Component Location:
The 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.

Conditions for Running the Diagnostics:
This diagnostic runs when the aftertreatment fuel shutoff valve is commanded on.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected the aftertreatment fuel shutoff valve pulse width modulated (PWM) signal was at system voltage when the pulse width modulated (PWM) signal was commanded OFF.

Action Taken When the Fault Code is Active:
1) The ECM illuminates the amber CHECK ENGINE lamp and/or the Malfunction Indicator Lamp (MIL) immediately when the diagnostic runs and fails.
2) Active regeneration of the aftertreatment diesel particulate filter will be disabled unitl the next key cycle.
3) 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 Code:
1) To validate the repair, start the engine and perform the INSITE™ electronic service tool Aftertreatment Diesel Particulate Filter Regeneration Test.
2) The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
3) The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
4) 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.
5) 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 Talk:
N/A

Possible Causes:
1) Fuel shutoff valve signal wire shorted to a voltage source in the harness
2) A damaged aftertreatment fuel shutoff valve