To return your vehicle back to stock using the GTX do the following:
- Turn the ignition to the "Run" position, do not start the engine
- Go to the main menu by tapping the top of the screen
- Select the "Tune" icon
- Follow the instructions on the screen
- You can skip the "check for Updates"
- Follow the instructions on the screen and select Return to Stock when that option shows up at the bottom of the screen