PACCAR PX-9 CM2350 (2013-17) Fault Code1926 PID:SID 332 SPN:3480 FMI:2 Aftertreatment Fuel Pressure Sensor – Data Erratic, Intermittent, or Incorrect

Reason:
Aftertreatment Fuel Pressure Sensor – Data Erratic, Intermittent, or Incorrect. The ECM has detected that the aftertreatment fuel pressure signal is not changing with engine operating conditions.

Effect:
Possible reduced engine performance.

Circuit Description:
The 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 Location:
The aftertreatment fuel pressure sensor is located in the aftertreatment shutoff valve assembly.

Conditions for Running the Diagnostics:
This diagnostic runs during active regeneration of the aftertreatment diesel particulate filter.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected the aftertreatment fuel pressure sensor was reading an erratic value, or the aftertreatment fuel pressure reading was not changing with the engine operating conditions.

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) A default value for the aftertreatment fuel pressure sensor reading is used.
3) Active regeneration of the aftertreatment diesel particulate filter will be disabled unitl the next key cycle.
4) 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) A malfunctioning in-range aftertreatment fuel pressure sensor
2) A plugged fuel filter
3) A malfunctioning fuel pump gear pump