Whirlpool WDF520PADM5 dishwasher has water in bottom after cycle. Dishes are clean and the water in the bottom seems clean. Diagnostics give code 6-4 (using 123-123-123 diagnostics service test mode). Things that have already been done:
1. Cleaned upper and lower filters and checked for debris.
2. Took off drain hose and ran water through it. No obstruction.
3. Tried running water through hose backwards and it won't flow so the check valve seems fine (the check valve is in the black, right-angle part of hose where it joins the bottom next to pump).
4. Checked float valve and it moves freely and I hear click of switch.
5. Checked that water filling stops when I open the door during a fill
6. Checked that the dishwasher is level (it is and it was working for a few years with no changes to level)
7. Removed drain pump. I can hear a little water inside when I shake it so I replaced it with a new one, but the problem persists and the diagnostics set the same 6-4 code.

I think I have chased everything the Tech Sheet says to check with a 6-4 code.

Anyone have any ideas or thoughts on what's wrong or what I can do at this point?

Thanks,
Dave

Edited by user Tuesday, December 28, 2021 11:06:31 AM(UTC)  | Reason: Not specified