If the tub was overlfowing but the water is able to drain out, the pressure switch hose is probably just plugged. That hose is plugged directly onto the main control board (number 1 in the diagram at the link below).
With the machine unplugged, remove that hose and blow through it to make sure it is all clear. If you find it was plugged, that should restore normal operation. If you clear it and the problem continues, the pressure circuit in the main control is faulty and the control will need to be replaced.
The link below is to the part you will need from a highly recommended company rated A+ with the Better Business Bureau. They offer a 100% money back guarantee, EVEN ON INSTALLED ELECTRICAL PARTS, for an entire year! They are the only company to allow returns on installed parts for a refund and offer a FULL ONE YEAR WARRANTY!
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