Cummins X15 CM2450 X124B (2018 & Newer) Fault Code: 2635 PID: SPN: 641 FMI: 31 VGT Actuator Driver Circuit- Condition Exists

Circuit Description
The variable geometry turbocharger (VGT) is electronically activated by the VGT actuator. The VGT actuator is a smart device and receives information via the J1939 data link from the primary engine control module (ECM). The VGT actuator performs its own diagnostics and reports malfunctions back to the primary engine ECM, using the J1939 data link. The ECM then decodes the error message and converts it to a fault code.

Component Location
The VGT actuator is located on the turbocharger bearing housing.

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
This fault code can be activated for the following reasons:

The Engine Control Module (ECM) detected a calibration incompatibility between the VGT actuator and the ECM calibration.
The Variable Geometry Turbocharger (VGT) detected the system voltage was incorrect for the VGT actuator part number.
The Engine Control Module (ECM) detected an incorrect VGT actuator installed on the turbocharger.
Action Taken When the Fault Code is Active
The ECM illuminates the red STOP ENGINE lamp and/or the Malfunction Indicator Lamp (MIL) immediately when the diagnostic runs and fails.

VGT actuation will be disabled.
Active and stationary regeneration of the diesel particulate filter will be disabled.
Exhaust Gas Recirculation (EGR) valve operation will be disabled.
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, perform a key cycle, 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 red STOP 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
This fault code is logged when the ECM has detected that an incorrect VGT actuator has been installed on the turbocharger.

Possible Cause:
1) ECM code incorrect for Engine CPL
2) ECM calibration