Indesit dishwasher puzzle???????????

Went to an Indesit IDF125 yesterday which customer complained was not washing properly and as soon as I turned it on could hear that the circ motor had had it. Tested heater which read ok (just in case!) and returned today with a new motor which is the crappy Askoll type. Fitted the motor which I did by removing RH side panel and tilted dishwasher slighlty to access easier. I find this easier than going underneath and struggling to seperate the motor and heater housings as better leverage from the side.
New motor went in like a dream, switched on to test, filled, pressure switch cut in, filled a bit more then 1st and 3rd lights started flashing (wash and end lights)and machine pumped out. I have checked and triple checked everything I did and cannot see why it will suddenly not work. I think those lights refer to a blocked filter? At no time does any voltage get applied to the motor and I have done a continuity check from the module sat in the base to the motor and heater and everything checks ok. It points to a duff board to me but I am puzzled as to why yesterday it worked, albeit badly and now today it errors out. Also how does this machine sense a blocked filter as the only flow sensor is on the inlet pipe? I have checked the pressure switch and hose and nothing untoward there either. It was a last call so I spent a long time there trying to fathom this but I have to admit it’s got me beaten! Any ideas anyone? 😕 😕 😕