This dishwasher has worked well for 2 years, but has recently started leaving several inches of water in the bottom when the cycle is over. The pump appears to be working. It runs when it should, but only pumps part of the water out. I have checked the drain inside the dishwasher for obstructions. I have checked the drain hose for kinks and obstructions. All have come up clean. When I unhook the drain hose from the back of the dishwasher, the water drains onto the floor, so there doesn't appear to be a blockage there either. I'm at a loss as to what to check next.