Kitchenaid range model YKDRS807SS00

I have to turn the breaker off the range to stop the constant beep. On the display it first asks for the time off day, which I enter. It then asks me for the probe temperature. I do not use a probe, but I enter 190 degs and push start. then it asks me to select cook method which I set convection bake and then start. The oven starts but only goes into Lo oven temp. I have tried different temperatures and cooking methods, but noting but Lo temp. Also the oven light stays on all the time?? We have had the range approx. 8yrs but only used it for approximately 4 yrs. This happen about a yr ago and the tech really did not have any idea what the exact problem was, and I think it was mentioned about the probe, which was never used. I think it probably is the main control circuit, but that is $400+ and I cant return it if that is not the problem, and who is to say if this will not happen again. I asked Kitcheaid website what to do and not surprising they said they were not aware of this problem and I should probably call a tech. Go figure eh! any help or suggestions other than buying a new range?