CM2150 Electronic Control System – FAULT CODE 2634

VGT Actuator Controller – Bad Intelligent Device or Component


Fault Code: 2634
PID: S027
SPN: 641
FMI: 12/12

VGT Actuator Controller – Bad Intelligent Device or Component. An internal error has been detected by the smart VGT controller.

VGT actuation will be disabled.

ISB, ISC, and ISL – VGT Actuator Circuit

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. Refer to Procedure 100-002 in Section F.

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 light immediately when the diagnostic runs and fails.
  • VGT actuation will be disabled.

Conditions for Clearing the Fault Code

The diagnostic will clear at initial key-on if the error condition no longer exists. The ECM will turn off the amber CHECK ENGINE light and enable VGT operation immediately after the diagnostic runs and passes.

Shop Talk

Verify the electronic control module (ECM) calibration is correct. Check the calibration revision history found on QuickServe™ Online for applicable fixes to the calibration stored in the ECM. If necessary, calibrate the ECM. Refer to Procedure 019-032 in Section 19.

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.

The aftertreatment system must be inspected after making the appropriate repair outlined in this fault code troubleshooting tree. Progressive damage to the aftertreatment system may have occurred. Perform the aftertreatment initial check procedure to test for a damaged diesel particulate filter.

For ISB engines, see the following procedure in the ISB CM2150 Service Manual, Bulletin 4021578. Refer to Procedure 014-013 in Section 14. For ISC and ISL engines, see the following procedure in the ISC and ISL CM2150 Service Manual, Bulletin 4021569. Refer to Procedure 014-013 in Section 14.

Refer to Troubleshooting Fault Code t05-2634

Last Modified:  20-Jul-2010