Whirlpool dishwasher not draining

Dishwasher was installed when house was built in aug 2004. It has worked fine until now. I noticed a lot of steam coming out of it and the bottom is full of water. I cleaned out anything I could find in the bottom and tried pouring baking soda and vinegar and then boiling water down the drain but it never drained. I’m assuming the drain is in the bottom around the large round deal. This dishwasher doesn’t have a basket. I opened the air drain on the sink but I don’t know what I’m looking at. Just a small tube inside a larger tube filled with water. Should there be water in there clear up to the top of the small tube? That is the extent of my knowledge on the subject. It was grinding loud a several weeks ago but that stopped finally.

Donna

I read the similar threads under my comment and this is what helped me..

"The second thing I would check is the check valve (#15 on the pump & motor break down diagram).

Remove all water from the dishwasher, remove the bottom panel, disconnect the drain hose from the check valve and unscrew it. Check for any clog."

It as a bugger to get back together but now it works fine. Thanks!