diplomat adp8322 fault?

Hi,
my Diplomat dishwasher has been out of action for some time and I am fed up with washing up! Can anyone help me find fault and fix please?

It is flashing/bleeping fault 4 flashes way into cycle.
There is no obvious sign of excess water in the bottom and I have gently cleaned in bottom and swished through boiling water .Lots of forums I have looked at seem to lead to replacing the pressure switch is this likely to be worthwhile and and tips for easiest way to replace it if I do?

Look forward to some helpful wisdom.