Dealer can’t program new key and fob for Fiat 500
Then try a locksmith or a different dealership.
Simple process for a competent technician.
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Welcome to the world of Fiat.
Something not working with a Fiat, and the dealer can’t fix it? Nothing unusual there.
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A post from one of the Fiat 500 owner’s forum’s explains the process, unless you ordered keys from Fiat with the vin or have lost both keys you’re probably in a tight spot
Need replacement key | Fiat 500 Forum (fiat500owners.com)
"I’m going to explain the entire process to ensure that future searchers coming across this are not fooled into thinking this is as easy as 1,2,3. In short you were lucky.
Fiat uses a crypto key transponder system. There is a secret key that is shared by the car’s Body Control Module (BCM) and the transponder. It’s a write once system where the key can be written once on the transponder and then locked. After that it cannot be neither read nor changed again.
So the process of taking a blank unwritten transponder, getting the secret key for the BCM, writing it to the transponder, and locking it is called precoding. All of this preceeds what is considered “programming” of the keys, which is simply authorizing a new, already precoded key to the BCM.
So one cannot program a blank key because it’s not precoded. One cannot reuse another key because it’s already precoded to another BCM.
Fiat precodes by keeping a database of BCM secret keys based on VIN. So they take a blank transponder, precode the secret key, and send it to the dealer. The dealer then “programs” the already precoded key.
The other path, the “lucky one” in this case is to find a locksmith that has the ability to extract the secret key from the BCM. This is done either via OBD port or by physically removing the BCM from the car, extracting the chip with the secret key, and reading it. Once the secret key is in hand, it can be precoded into any number of blank transponders, producing new keys that can be programmed for the car.
I personally tried about 10 locksmiths and none had the equipment to precode from the BCM. In the end, I had it done with the dealer. Cost $280.
Finally, do not break or lose your last key. A Fiat with the alarm activated and no valid key will melt the BCM, permanently disabling the car. The car will have to be towed, the BCM replaced, and new keys precoded and programmed to the new BCM. My best advice is if you only have your last key, only lock the door from the outside and never use the fob to lock. Locking from the outside deactivates the alarm. Losing the last key then eliminates having to replace the BCM. I also had two non transponder keys cut. They unlock the car but will not start it.
If I had to do it all again, I’d likely bypass all the security by embedding the last working fob in the car and driving and locking the car with non transponder keys. It eliminates all the hassle and makes new keys both easy and cheap.
I have been told Fiat and Piaggio use the same key technology.