AGT? You mean VGT solenoid. I have never heard of one seizing in the turbo but I guess anything is possible. You would have to be pretty brutal with it too as the solenoid is not an easy part to break. THere is now access directly across in the bore which is blocked by the actuator cam... soo if you cannot get it apart it is new turbo time. You can replace just the center rotating housing which contains the VGT solanoid.