I could not figure this out and finally replaced the pump and it still would not drain. I finally pulled the dishwasher out and laid it on its back and pulled off the drain tube connected to the bottom of the dishwasher. I blew in it and air would barely go through. The problem was that the flap that prevents water from flowing back in the dishwasher had come through the small opening and was on the wrong side. I pushed it back through and now everything works fine. I would guess that there was enough backpressure from the garbage disposal when it was full of food to grind that it pushed that valve through. You do not need to pull the whole dishwasher out to fix this but I was at a point of checking everything so that is why I did. Could have been much cheaper as it only took me a couple of minutes to push the valve back through. I will see how it works out as I am not sure if the valve has been damaged. If it is then I will need to replace the hose. At least I know what to look for now.