PACCAR PX-9 CM2350 (2013-17) Fault Code:3571 PID: SPN:4334 FMI:3 Aftertreatment 1 Diesel Exhaust Fluid Pressure Sensor Circuit – Voltage Above Normal or Shorted to High Source

Reason:
Aftertreatment Diesel Exhaust Fluid Pressure Sensor – Voltage Above Normal or Shorted to High Source. High signal voltage detected at the aftertreatment diesel exhaust fluid pressure sensor circuit.

Effect:
Possible reduced engine performance

Circuit Description:
The 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 Location:
The 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 Diagnostics:
This diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running.

Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected the aftertreatment diesel exhaust fluid pressure sensor signal voltage was out of range high.

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) Diesel exhaust fluid injection into the aftertreatment system is disabled.
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, perform a key cycle, start the engine and let it idle for 1 minute.
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:
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 Causes:
1) Signal wire shorted to sensor supply or battery voltage
2) A malfunctioning aftertreatment diesel exhaust fluid pressure sensor