Cummins ISX12 CM2250 (2010-12) Fault Code: 3575 PID: SPN: 4334 FMI: 16 Aftertreatment Diesel Exhaust Fluid Pressure Sensor- Data valid But Above Normal Operating Range- Moderately Severe Level

Circuit Description
The diesel exhaust fluid controller provides a 5 volt supply and a ground to the diesel exhaust fluid pressure sensor. The pressure sensor provides a signal to the diesel exhaust fluid controller on the sensor signal circuit. This sensor signal voltage changes based on the diesel exhaust fluid pressure supplied by the dosing unit. The diesel exhaust fluid controller will detect a low signal voltage at low diesel exhaust fluid pressures, and high signal voltage at high diesel exhaust fluid pressures. The aftertreatment diesel exhaust fluid pressure sensor reading is communicated to the engine control module (ECM) via the engine data link.

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.

Conditions for Setting the Fault Codes
The aftertreatment diesel exhuast fluid controller has detected that the diesel exhaust fluid pressure in the dosing unit is above 1250 kpa [181 psi] for more than 20 seconds.

Action Taken When the Fault Code is Active
The ECM illuminates the amber CHECK ENGINE lamp and/or the malfunction indicator lamp (MIL) immediately when the diagnostic runs and fails.
Engine torque will be reduced if the engine is operated for a limited period of time with the fault code active.
Engine torque will be severely reduced and vehicle speed will be limited to 8 km [5 mi] per hour after extended engine operation with the fault code active.
Conditions for Clearing the Fault Code
To validate the repair, perform the “Aftertreatment Diesel Exhaust Fluid Doser Pump Override Test” found under “ECM Diagnostic Tests” in the INSITE? electronic service tool
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 Talk
Troubleshoot other active selective catalytic reduction (SCR) related faults before this fault.

Possible causes of this fault code include:

Blocked, restricted, or frozen diesel exhaust fluid dosing unit return line or return line fitting
Malfunctioning diesel exhaust fluid dosing unit.
Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.

For intermittent power supply and data link 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 Cause:
1) Aftertreatment DEF dosing unit failure
2) ECM calibration