Would like to know if a new control panel is needed because the panel lights up and works, but the start button is the only one that will not allow to be pushed. If you wait too long it shuts down.
Most likely the problem is a bad keypad but there is a small chance for the control board to be bad as well. I would replace the keypad first.
Here are the breakdown diagrams and Replacement parts for Frigidaire PLDB999AC0 Frigidaire/dishwasher | AppliancePartsPros.com
Gene.