I have a Whirlpool GU2500XTPB3 undercounter dishwasher. Everything seems to run fine, except that it does not drain at the end of each cycle. It fills and washes but then goes silent at the time it is supposed to be draining. It is as though the computer is not telling the motor when to drain.

The first thing I tried was resetting the computer by pushing 'hot wash,' then pushing 'hot dry,' and repeating. All the lights went on, and the computer cycled through. But that did not affect the draining.

It appears from parts diagrams that the drain pump runs off the circulation motor. But is there a relay that might be bad?

I have voltage at the drain pump, but the pump seemed to not run smoothly. So I have replaced the drain pump. Unfortunately, though I hear it run, water does not go out. I put the utility vacuum on the drain hose and could hear air at the sink, where the hose comes into the sink drain, so the hose is not clogged. I cleaned everything inside, including checking the chopper blade. I am at a loss to figure out why water is not draining.

Could the check valve be the problem? It does not want to pull out easily, so I have not removed it. I do not want to tear it up for no reason.

Not sure it's a good idea to eliminate the check valve- you might get some backflow from the sink, and flood the dishwasher. Also, when the d/w drains, water in the hose might backflow into the basin, making the heater coil inoperative, or (boiling the water during the dry cycle?)