Your symptoms point to a stuck key or failed control console keypad. A failed electronic control board could also cause this problem. The normal procedure for repairing this type of problem is to replace the control console first. If the problem continues, then the electronic control board would need to be replaced. You may want to have a service technician complete this type of repair since there are no tests to check the console keypad or the electronic control board to determine which one is the failed component.