yesterday while driving the car cut out and noticed the temp gauge went suddenly to the right.and as it kicked back in went straight back indicating an electrical problem.When i stopped at my destination it wouldnt restart showing padlock on ignition.noticed the the 3rd relay down a red one in engine compartment fusebox was clicking with key turned. evenyually it started i got home it wont start again.checked ecu with fiatecu scan and no fault codes.not showing padlock but showing enginge magement light on key turn.could it be ecu,or relay,or posibly a key problem it is showing symptym as if wrong key is being used.Help!

update used a memoscan can obd 2 and came up with following fault codes,erasure followed by restart and codes were back unfortunatley i dont have code book.

fault codes p0105 ,p0500,p1325

P0500- vehicle speed sensor fault
P0105- faulty air pressure sensor
P1325- I think its the knock sensor not 100% percent on that

Well thanks to looking at threads on the Fiat forum i finally found the problem. It was a loose Earth wire to the throttle housing(the black one).So if your Punto wont start and the red relay in fuse box in engine compartment is "clicking" check this lead first,it could save you a lot of time and expense!