Cummins ISX12 CM2250 (2010-12) Fault Code: 3577 PID: SPN: 4376 FMI: 3 Aftertreatment Diesel Exhaust Fluid Return Valve- Voltage Above Normal or Shorted to High Source

Circuit Description
The aftertreatment diesel exhaust fluid return valve is controlled by the aftertreatment diesel exhaust fluid controller. The return valve position determines where afterteatment diesel exhaust fluid will flow as it exits the dosing unit. When the return valve is energized, the dosing system will purge and return the aftertreatment diesel exhaust fluid in the lines to the tank.

Component Location
The aftertreatment diesel exhaust fluid return valve 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 exhaust fluid controller detects that the aftertreatment diesel exhaust fluid return valve voltage is more than a calibratible value for 1 second.

Action Taken When the Fault Code is Active
The electronic control module (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 an extended period of time with this fault active.
Conditions for Clearing the Fault Code
To 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 Talk
If this fault is active, the dosing system may not be able to purge, which means there will be aftertreatment diesel exhaust fluid left in the lines. Care must be taken when removing connections. Also, lines can freeze and the SCR system can become damaged in cold weather if the system is not properly purged.

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 Cause:
1) Aftertreatment DEF fluid controller failure
2) ECM calibration