Fiat Reviews

If this was a problem with the actual transmission, you’d find the problem would probably not come and go. But since it’s dependent on the battery being disconnected and then reconnected, the smart money says it’s a problem with either a sensor that sends information to the driveline computer, or the computer itself.

You could start by scanning the vehicle to see if a dud sensor reveals itself. But you may also find that a replacement ECU (computer) is the ultimate fix.

Assuming the vehicle is starting and stopping correctly via the start button, you could be looking at anything from a faulty component in the switch’s lighting circuit, to a bigger problem with the car’s body computer. An auto electrician should be your first stop to get it sorted.

But until you can book in to an auto sparkie, try this trick at home. Disconnect the battery and leave it disconnected for an hour or so. Then reconnect it and see if the problem has gone away. Sometimes, a body computer needs a reset, and disconnecting the battery is the equivalent of Alt-Ctrl-Delete, or turning a computer off at the wall and switching it back on.

Fiat kind of skipped the hybrid step with its 500 range, and now offers both a petrol-engined and an all-electric version of the car. The 500X was more or less the SUV version of the Fiat 500, but that was discontinued in 2018. And there was no hybrid version of that, either.