I had the same problem when I tried to get on the treadmill today. The incline went up by itself and wanted to keep going even when it was fully inclined. I was able to get it to go down using the buttons, but as soon as it would get flat it would start inclining again. I got it flat AGAIN and turned it off.
I opened it up and unplugged the black and red wires from the top of the incline motor and turned it back on...it took a second to "unrecognize" the incline but then at least the rest of the system worked so we can run on it flat. Now I will see if i can find a replacement motor maybe? :( hope this helps
Bonnie
April 2009