The "F35" error code is indicating a problem with the ANALOG PRESSURE SENSOR switch operation (key#20). There could be a blockage in the air dome or pressure switch hose. The pressure switch is located underneath the main top on the right hand side. (See image) The air dome is located on the back of the tub on the left hand side. If the pressure switch hose and the air dome is clear of any blockages the likely failure is the water level pressure switch (key#20) part# W10156252. Replacing the pressure switch will likely resolve the "F35" issue.