I have a 3 year old Whirlpool WDT750SAHZ0 dishwasher that intermittently does not drain at the end of the cycle. It drains manually when I hit the drain button. I checked all the filters, removed the pump motor and it looked and functioned fine. Replaced the drain tube with built in check valve just to be sure, and made sure there were no restrictions in the drain line, air gap and garbage disposal. Ran 2 cycles and it drained fine, third cycle water in the bottom.

Any further insights would be greatly appreciated.