Fred--thanks! I took off the front access panel using the diagram you have attached and then took off the drain pump filter. Clogged in the filter was a quarter, piece of metal from clothing, lint, and a baby wash towel. That the was the problem--all that junk causing the F21 error message. Saved me $$$ from calling a repair man. I had a lot of water to clean up but the washer now works great! I am glad to have individuals like yourself helping out the common man!