Dishwasher not draining fully

Removed screws on the drain pump filter screens at the back of the dishwasher, unscrewed the check valve, screwed in the replacement unit, and re-affixed the filter screens.

I lived with the drain problem for 6 months and reviewed on line trouble shooting which all pointed me to a pump or solenoid valve problem. I pulled the unit and disassembled everything before noticing that the rubber washer/stopper at the top of the check valve had erroded away and was not preventing water from pumping back into the cabinet when the drain pump kicked on. Always check the condition of this check valve first if you dishwasher is not draining properly. It was so easy once I found the bad part.