Circuit DescriptionThe variable geometry turbocharger (VGT) is electronic 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 LocationThe VGT actuator is located on the turbocharger bearing housing.

Conditions for Running the DiagnosticsThis diagnostic runs when the keyswitch is initially turned to the ON position.

The keyswitch must be completely turned OFF for more than 30 seconds before this diagnostic can run at initial key ON.

Conditions for Setting the Fault CodesThe internal position reference is not detected during the initial power ON due to incorrect installation of the VGT actuator. The actual VGT actuator position is not known.

Action Taken When the Fault Code is ActiveThe 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.Conditions for Clearing the Fault CodeTo validate the repair, perform a key cycle, and leave the keyswitch in the ON position for 1 minute. Note that the keyswitch must be completely turned OFF for more than 30 seconds before this diagnostic will run at initial key ON.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 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 TalkThis fault code can only be logged after the VGT actuator has been removed or replaced, and then not installed correctly. The gear alignment between the actuator and the turbocharger housing is misaligned. The correct installation procedure must be followed when replacing the VGT actuator.

Possible Cause:1) Turbocharger Failure2) VGT Actuator Failure3) ECM calibration