I explain when the program at any stage of filling what it does is open the selenoid so that the water enters ... How does the washing machine know when it has reached the level of filling that was programmed? Well, for a pressure switch that is in the tub, that's why in the automatics you should not use soap powder ... Now if the machine is knobs, it will be necessary to disassemble and clean pegs. if it is digital it will be necessary to see where these signals come from I don't tell you because it's hard to work without photos or diagrams