Our Bosch dishwasher gets a clogged drain every few months. I’ve worked out the routine to clear it: use a hand pump clear out the standing water in the dishwasher, remove the filter, remove the little rubber check valve, then blow compressed air back through the air gap to clear the clog. Clean out the bottom of the sump, and reassemble. It takes about 15 minutes, and it’s not my favorite job.
Often the culprit is a pea or bean that got through the filter basket somehow. I’ve replaced the filter, but it didn’t help. My family has gotten very careful about scraping plates before loading dishes, but I don’t think this should be happening so often. Why do pieces large enough to clog the drain make it that far? Could the drain pump be too weak to push the pieces through the drain?