I just got a used Whirlpool duet frontloader washer WFW9150WW that will not drain. I checked the drain lines and drain pump for debris and found nothing. I'm thinking the drain pump is broken. I bought it off craigslist and the previous owner claims it always worked great. Not sure if it's a line or if something happened while bringing it home (30 minutes in a trailer). The washer will load and fill, but beeps and flashes an error when it tries to drain. I've opened the front and emptied the water three times hoping to find a clog but no luck. How do I know if its the drain pump? Could it be a sensor? Any thoughts? Thank you!

I just fixed my draining problem with this washer. I could hear the drain pump running, but not much water was moving. There is a filter next to the drain pump. Remove the 3 screws in the bottom panel (near the floor) and then remove the panel. The drain pump is in the lower right front. Can you hear and feel it running? If it is running, the filter may be plugged. On the lower right is a removable cap. Mine was plugged with tape, lint, coins, hair bands, etc. Remove the cap slowly. Water will come out when you pull the plug so have some tupperware to catch the water until it stops.

I scanned the service guide that was inside the washer but it wont let me upload it.

Added some before and after photos.

Thank you Tim. I read your post. My washer wouldn't drain all the way. I found this site read your post and was able to tell my husband where to look. There was a sock, some other piece of clothing, money, sand, lint and small stuff in the filter!!! Works great now!!!!