I just installed a used Kenmore Ultrawash Dishwasher and it won't drain completely. I put a new hose on it, so there's no obstruction. It leaves about 2"+ of water in the bottom of it - does sound like the pump is working okay.

You might check the drain/fill float, usually located at the rear of the washer. If the float is bad this would be one reason why water is left.

Also check the pump water intake grates/grills to make sure they are clean and open to allow full water flow.