The 2 most common part(s) or condition(s) which cause the symptom Dishwasher overflowing are listed below starting with the most likely. Check or test each item and watch any available videos.
RepairClinic Item # 3015273
Every dishwasher has an electrically controlled water inlet valve. The valve stays open either for a set length of time or until the dishwasher has enough water - depending on the model. However, if the water inlet valve doesn't shut off properly when the dishwasher has enough water, the dishwasher overflows. If water ever drips into the dishwasher with the door open, or if there is a lot of fresh, clean water in the bottom of the dishwasher after it has been sitting unused, the water inlet valve may need to be replaced. If there is allot of suds in the bottom the unit may be over sudsing and reducing the soap used may solve the problem.
RepairClinic Item # 903948
The float switch is actuated by the float assembly. It is a protection device designed to prevent the dishwasher from overfilling. If the dishwasher overfills with water, it may be because this float switch is defective or stuck.