Fiat brava 80sx cutting out stalling HELP?

Hi my fiat brava keeps cutting out at junctions or not long after idle or when i dip the clutch and brake it cuts out can be dangerous i have plugged it into a diagnostics machine and its giving me every code possible it also said my car has been down to -31oC ive changed temp sensor and it has fixed that problem but my mechanic thinks the ecu could be completely destroyed and could cost 600 so now im here asking for your help suggestions anything may help its a Fiat Brava X reg 1.2 80SX Thanks in advance