Could be metallic obstruction on the bay floor (foil) or a faulty home prox sensor. Try sweeping the bay floor first, then unscrew the cable on the home prox, spray the electrical pins with wd40 and re connect it, checking to ensure the sensor is not loose. (The home prox is found by removing the bottom drivers side panel, then it is pointing down at the floor on the exit side of the wash). If this doesn't work, replace the sensor.