Fiat 500 Key Fob Replacement
If your 500 key fob isn't working, try using another one to see if the car can detect it. If it does, then the problem is probably due to the battery or water damage to the fob that was originally used.
First, replace the battery. Make sure that the new # CR2032 coin cell battery is properly inserted with the "+" side facing downwards in the fob.
Dead Battery
The majority of the time, when a fob won't work, it's because the battery is dying. This is a simple repair and most fobs notify you that the battery is getting depleted. You can find instructions for the majority of car fobs on YouTube or in your owner's guide. You can also change it by taking it to an authorized locksmith or a dealer who gave it to you.
Sometimes a fob stops working due to a glitch on the circuit board inside. This isn't very common however it can occur. If you dropped the fob on something sharp, it could cause damage to the internal chip. It could also happen if you use an aftermarket fob and the key does not work. In this case, it is necessary to go to a dealer or locksmith to have the key reprogrammed to make it compatible with your 500.
One 2012 FIAT FIAT 500 flip key remote – Looks like Ilco with lock, unlock and trunk buttons - new keyless entry replacement (will require cutting and program by locksmith).

Chips that are damaged
Fiat 500 key fobs are wireless devices that send a signal to the car whenever you press the button. It is equipped with a microchip that contains information about the code needed to communicate with your car. If the chip is damaged, it won't transmit the correct code, and the car won't begin. It is possible to repair this kind of damage and a locksmith will assist. United Locksmith can complete this service on both classic as well as modern models, so do not be afraid to contact us.
A locksmith can program the new key fob. This is a lot less expensive than going to a dealer and will function similarly. You'll need some details to the locksmith, like the year in which your car was manufactured and its model.
Rub the chip with an old dollar bill if you're not sure what to do. The copper in the bill is abrasive, and will remove dirt and oxidation. However, it will not cause harm to the microchip. The chip may not be repairable when it's physically damaged. This could happen if drop it, knock it over by accident with your vehicle, or some other kind of physical strain.
fiat 500 replacement key cost
If you've accidentally dropped your keys in the pool, put them in your bag while swimming at the beach or splashed them with water on a rainy day it's likely your fob will have some water damage. Even if you only have a small amount of water on the key, it could cause serious problems with its electronics.
The good news is that it is possible to solve this issue by removing the fob's key and then using the paper towel to cleanse it of any remaining dirt or water. Once the fob has dried and is dry, you can replace its battery. It will then begin working normally.
You could also take your fob to a local locksmith shop or auto shop to get it professionally cleaned and programmed. These professionals will use special equipment to make sure that the key fob functions with your car's computer.
If the key fob of your Fiat 500 stops working, you may feel irritated and overwhelmed. It is tempting to head to the dealer to get your key fob replaced, but this can be costly and inconvenient. Locksmiths can replace your key fob without needing to visit a dealership. They are a better choice over a dealer as they can handle every aspect of your car's key fob replacement without the need for a dealer visit.
Pairing Issues
If you drop your key fob or it ceases to function and nothing else appears to be the issue there could be a chip that is malfunctioning. This could be due water damage or a dead battery, or it may be due to a need to reprogramme.
In most cases, this can be accomplished by following the directions in the owner's manual. If you're having issues or your manual isn't working it is recommended that you have an auto locksmith do this task. This ensures the chip isn't fried and will likely be the most cost-effective solution.
A number of owners have reported that their keys will not lock their cars. This can be a problem if you plan to fill up at gas stations. Some owners have complained that their 500's locking system failed and they had to replace the entire intermediate steering shaft. This problem has actually been mentioned in a technical service bulletin (TSB) from Fiat.
A reputable locksmith is able to assist you if your Fiat is experiencing problems. They can duplicate your key or make you a brand new one that locks and starts the vehicle. They're able to do this without ever seeing your key, and are typically much cheaper than getting it from the dealership.