I had the same problem. I did the following.
- unpluged washer
- drain washer
- tilt back washer on wall.
- The problem was coins, and dryed soap in drain hose.
- You can un-clamp hose without tools using for fingers.
- Pull hose off.
- If there is a blockage this may be your problem too.
- Clean with shop vac and needle nose pliers.
- Re-connect hose.
- Your done