ulysse starting problem

hi all been reading site thoroughly to see if i can get any details to my problem, i had an accident i my ulysse drivers side. the wing, lights were broken but nothing major. i found that i could no longer start the car so i pressed the restart on the red button still no joy. i noticed a relay of some kinds was broken next to the ecu so i phoned fiat & they told me that a replacement would solve the problem so i replaced it still no joy. so i decided to u easy start spray, eventually it got it going but when i tried to rev it would cut out . but it would tick over ok. so i decided a reset, negative off left overnight put it back on still no joy. so auto spray got it going again & i drove it to garage for diagnostic orange engine light on. kept cutting out but got there in the end, diagnostic read, said rear cat sensor 0 voltage, h20, petrol, hose. etc. i checked all pipes couldnt find split or anything so i am now stuck . do u think the ecu could be damaged ??????

thanx to everybody that replied even to say i av no idea to let everybody know that might av the same problem it was the fuelpump....or sender as its called for this model. i got the fiat cd off ebay £5.00 well spent

Glad you got it sorted in the end