Cummins ISB4.5 CM2150 Fault Code: 2634 PID: 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 the malfunction indicator lamp (MIL) immediately when the diagnostic runs and fails.
-VGT actuation will be disabled.
-The VGT actuator will stop controlling the turbocharger.

Conditions for Clearing the Fault Code
-To validate the repair, perform a key cycle. The diagnostic will clear at initial key ON if the error condition no longer exists.
-The ECM will turn off the red STOP ENGINE lamp and enable VGT operation immediately after the diagnostic runs and passes.
-The ECM will turn off the MIL after 3 consecutive ignition cycles that the diagnostic runs and passes.
-This fault code and MIL can also be cleared with INSITE™ electronic service tool.

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.