I have a Nordictrack A2105 treadmill that the incline isn't functioning properly. It only goes up to 2.0 when you increase the incline. You can continue up to 10.0 but the incline doesn't raise past 2.0. The when you take the incline back to 0, the incline will go back down. Is there a sensor that I can replace or adjust? I tried to calibrate it according to the manual but it continues to do the same thing. Any help is greatly appreciated.