Hi I have a bosch classixx 1200 express with an intermitent fault where it wont drain the water before the conditioner goes in, sometimes if you bang the fluff filter really hard it kicks into life, but its getting to the stage where you have put it onto the rinse spin cycle which works fine no banging. The impellor seems to be fine and pipes not blocked. Would this point pump problem or control board.
as these pumps get older they get to the point of starting when they feel like it
if you are banging the filter without turning it off and it starts they likely its the pump.
take a look at the impellor look for cotton wrapped around it before you condemn it