Product review (3 stars): F-35 Problem Solved--NOT ANYMORE
Whirlpool Duet 5900--three years old, but gets lots of use with three kids
Cleaned hose inlets, trap in bottom of washer, cleared pressure switch hose--none worked

Arrived in one day from Las Vegas.  Plugged it in, ran the diagnostic--all clear.
Just finished the load of clothes that had been sitting for 36 hours with no issues.

UPDATE:  Second load of clothes and now I have a SUD error as well as a F-35