Model number: MDB7749SAB0

My dishwasher's drain pump will run at the end of the cycle even if the tub is dry. I looked underneath the unit and the drain hose still has water in it. I replaced the overfill float switch and electronic control. I still have the problem. The was wash cycle works normally. Any ideas?

Is it possible for something to be plugged where I cannot see it? What about a check valve being stuck?

This unit is only 1-1/2 years old and I do not want to replace it.