the CAN SYSTEM is the network that sends data bewteen all the computers on your car, something has disrupted it, the new radio is looking for the old car it came from , , it you read the fiat forums, you will see this problem, see if you can get the radio to come on and work ,, out of the car , just on a car battery and speaker, you might be able to clear that setting then,, good luck
h, July 2014
