Cummins X12 CM2350 X119B (2018 & Newer) Fault Code: 4157 PID: SPN: 4376 FMI: 7 Aftertreatment Diesel Exhaust Fluid Return Valve- Mechanical System Not Responding or Out of Adjustment

Circuit Description
The aftertreatment diesel exhaust fluid return valve is used to purge the aftertreatment diesel exhaust fluid dosing system. When the return valve is energized, the dosing system will purge and return the aftertreatment diesel exhaust fluid 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 only runs when the aftertreatment diesel exhaust fluid dosing system is purging.

Conditions for Setting the Fault Codes
The Engine Control Module (ECM) detected the aftertreatment diesel exhaust fluid pressure did not drop when the aftertreatment diesel exhaust fluid return valve was commanded on.

Action Taken When the Fault Code is Active
The ECM illuminates the amber CHECK ENGINE lamp and/or Malfunction Indicator Lamp (MIL) after the diagnostic fails on two consecutive trips.

Conditions for Clearing the Fault Code
To validate the repair, perform the “Aftertreatment Diesel Exhaust Fluid System Leak 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 immediately after the diagnostic runs and passes.
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.
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
Possible causes of this fault code include:

A malfunctioning aftertreatment diesel exhaust fluid return valve

Possible Cause:
1) ECM calibration