Cummins ISX12 CM2250 (2010-12) Fault Code: 2634 PID: SID 27 SPN: 641 FMI: 12 VGT Actuator Controller- Bad Intelligent Device or Component

Circuit Description
The variable geometry turbocharger (VGT) is electronically activated by the VGT actuator. The VGT actuator is a smart device that receives information via the J1939 data link from the primary engine electronic control module (ECM). The VGT actuator performs its own diagnostics and reports errors back to the primary engine ECM using the J1939 data link.

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
The VGT actuator has detected an internal error in the VGT smart device.

Action Taken When the Fault Code is Active
The ECM illuminates the red STOP ENGINE lamp and/or 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.
The EGR valve will be closed.
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 red STOP 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
This fault code is logged when the VGT smart actuator detected an internal error within the VGT actuator. The VGT actuator will stop controlling the turbocharger when this fault code is active.

Fault Code 2634 will become active if the VGT actuator is removed from the turbocharger and then the keyswitch is turned to the ON position; or it may be possible for it to become active if the actuator fails the install/calibrate procedure. If this occurs, disconnect the VGT actuator from the engine harness with the keyswitch ON, and connect the VGT actuator to the engine harness. Fault Code 2634 should go inactive. Follow the VGT actuator installation procedure to install the VGT actuator.

Possible Cause:
1) VGT Actuator failure
2) ECM calibration