Frigidaire, fills then drains.

I have a Frigidaire dishwasher with digital timer that has the following problem. When you select any wash cycle it will fill with water, the timer display will jump ahead several minutes, and it will immediately start draining without running the wash cycle. It will do this over and over until it counts down to zero. If I keep cancelling and reprogramming it from the beginning it will eventually work after about 10 tries and run through all of the wash and rinse cycles normally. It sat idle for about 18 months in an empty house until this week. It worked before that time. Whether that has any bearing on this I don't know. Any suggestions would be appreciated. Thank you.