The motor in this dishwasher is reversible what means it turns in opposite direction for drain. Slowly turn the knob. The motor should stop for a few seconds and switch from wash to drain.
Did you figure out the problem? I have the same problem(same model Whirlpool DU811SWKU0). It leaves about 1 to 1.5 inches of water. I hear the motor turn. I took it apart, made sure check valve, ball, etc was clean. Even took out the drain pipes, gap and made sure it was clear. What could be wrong?
yes.. mine was a clogged drain line.. it was completely clogged with stuff.. thus the pump could not push the water thru. take your drain line out side and use a garden hose to make sure it is not clogged.