Put dishwasher in January, 2013 in kitchen island. Drain hose goes under floor to sink air lock and garbage disposer (and yes I knocked the hole out of the disposer). Total length of hose pipe is 12 feet which this model said it could pump. Has worked great until this last weekend. Now it is not draining all the way. Checked the screen and basket - was kind of clogged with snotty gunk. Thought that was the issue so cleaned that, put it back in and hit "drain" button. Motor runs, kind of clicks (maybe always sounded like that, never really listened that closely) and small amount of water comes through air lock on sink (again never looked before, but seems to be less than I would have expected). Got underneath and disconnected drain tube from pump. Water freely exits pump once disconnected and I am able to blow air through waste pipe to sink (although seemed harder than expected). Ran a half gallon of vinegar through drain. After a run there is still 3 inches of water at bottom of tub. I can hit drain button and small qty does pump out through air lock, but takes two or three times of hitting the button for tub to drain out completely. Does it seem more likely that it is a hose issue or a pump issue? Could the pump have burned out because the strainer basket was so clogged? Previous posts talk about a check valve, I couldn't find on in the drawing for this model. Any other way to check whether the pump is working without disconnecting it completely?

So I checked all the lines, from the pump to the air lock - no clogs, no buildup, drained them and able to blow through perfectly easily.

I will consider moving it to drain down to basement (washer/dryer right there and probably won't even need new hoses, just could go right into the washer p-trap). Maybe that will pervent this from happening again in future.

Still doesn't seem to address the slow drain though. Could it be the sensor? It reliably shuts off with the basin full of water. I can push drain, and it drains for a good minute or so, but the water is still up to the top of the basket. A second push of "drain" gets it all the way down. It seems so weird that the pump would work, but only at about 50% capacity.

Maybe I just need to get the pump out of there and clean the impeller? How do I get the drain pump off to see in there? Can I do it without taking the d/w out of the cabinet?

Below is the pump
Part number: AP4320199