Check if a button is not clicked

I am working with @DevilZ on his racing game. If you go to this scene, you will notice a gas pedal. Previously, you had helped me out in this thread with my problems letting a car’s rpm decrease in your third post on the thread. Is there any way to do the same here, the button being the control to rev the car up; the car’s rpm decreasing if the button is not pressed? I need mobile controls as well.