overfills with water and overflow doesnot work
The first thing I would do is check how freely the float (#15 on the break down diagram) is moving up & down.
Check the float switch (#11 on the break down diagram) for continuity and if it’s properly engaged by the lever.
Check if the water inlet valve (#7 on the break down diagram) is not stuck open.
Here are the break down diagrams for the Kitchen Aid dishwasher Model KUDD230B0
Gene.