Caple Di465

got a call from a customer to repair her Bosch SL dishwasher and by the time I got there it had turned its self into a Caple Di 465. the problem is that it drains it fills then drains again and E1 appears in window.E1 is longer inlet time. water pressure is fine and it flows into the air breather ok. I suspect its the flow meter situated in the breather but I also noticed there is a pressure switch fitted to the machine as well. done a few easy repairs on this make but don’t see many of them and don’t want to spend £25 on a part it might not be.
any help would be much appreciated. thanks