Reasons Your Fiat 500 Key Fob Won't Work A key fob from Fiat 500 allows you to easily open doors and start your vehicle. However, there are a variety of reasons why the fob won't be working. This could be due to a dead battery, water damage, issues with the receiver module, and interference. This listing is for an NEW replacement Fiat Flip Key Remote that appears similar to the Ilco brand. It must be professionally programmed (click here to search for local locksmiths for automotive locksmiths). It comes with lock, unlock and trunk buttons. Dead Coin Battery The most common reason your 500 key fob will not work is an inactive battery. https://www.thekeylab.co.uk/fiat-car-keys/ operate with a limited operating range, and should be within just a few feet of the car to operate. If you are far from your vehicle when you press the key fob button the car won't respond, and will display the "Key Fob Not Detected" message in the instrument cluster. If this happens, replace the battery in the coin cell (Part number CR2032) with a fresh one from a trusted brand such as Panasonic, Duracell, or Energizer. You can usually find them at your local hardware store or on the internet. After you've replaced the coin cell battery You can test it by standing near your Fiat 500 and pressing the buttons. The parking lights should light up and the key fob should operate the lock and unlock switch. If the fob's remote doesn't work after replacing the battery, it may have water damage that stops it from communicating with the receiver module inside your vehicle. Water damage can occur in a variety of ways, from an accidental splash to submerging the fob salt water at the beach. If you suspect your fob was exposed to water, you can try placing it in a dry rice bag to draw the moisture out. If this doesn't work your fob is likely to need to be reprogrammed by an experienced auto locksmith or dealer. Water Damage The fob does have rubber seals to keep water out of the electronic chip inside, submerging it in the ocean or washing it in a machine could cause water damage. Saltwater can cause the circuit board to short and eventually cease to function. It's not good to let the fob get wet, but don't give it up in the event that you accidentally drop it in water or fail to remove it from your pocket. First remove the battery from the fob. Clean the electronic chip with isopropyl or a similar product and dry it thoroughly before replacing the battery. Then check the fob to check if it functions. If the fob doesn't work it could need to be changed. This is typically done by a dealer or professional auto locksmith. If your key is older and not programmed for your vehicle then you'll need to replace it completely. A professional locksmith for cars can complete this simple process. The locksmith needs to cut the key to match the ignition of your car. They'll also have to reprogram the fob for the car's system. This is a cheap and quick process that could be completed in the same day. Receiver Module Issues Your 500 key fob may not function because it's out of range. The remote has a maximum range of 30 feet, which means should you be too far from your car it won't respond to your commands. It can be solved by moving closer to your vehicle until it begins responding. If your fob doesn't work after you replace the battery for the coin, also called a "button", "watch" or "button" it could be due to a problem with the circuit board inside. Reprogramming the fob typically resolves the issue. You can find directions on how to do this on the majority of automobiles by searching YouTube or reading the owner's manual. It is possible to replace the clips made of metal that hold the coin batteries in their place. If they become loose, it can stop your coin battery from sitting properly and cause your remote to malfunction. In rare instances it is possible that the fob will become desync'd with your vehicle due to software problems or hardware issues. It is possible to fix this issue by visiting your local auto-locksmith or dealer to reprogram your key fob. In some cases it is possible that the software will require reinstallation into your body control modules. Interference Interference can also cause the key fob to not be able to receive or transmit a signal. This can happen when the key fob is in proximity to radio transmitters (cell phones, radar detectors) or another source of electromagnetic radiation. The key fob could not work because of a weak connection to the buttons, water damage or damage to the internal chips. If the key fob has failed to work one day out of the blue and you've tried everything you can do at home to solve it e.g. replacing the battery, reprogramming, and using the spare key fob, you may have a damaged receiver module on your 500. The receiver module, which is located beneath the dashboard, detects radio frequency signals from your key fob. It converts the signals into electronic commands, which are then interpreted by the vehicle. There's a quick and easy way to reset the 500's internal system including the keyfob. Disconnect the battery for 15 minutes by removing first the negative cable, then the positive cable. Reconnect the battery. This will eliminate any remaining electricity and then restart the car's computers, which could help get your key fob working again. If the issue persists it is recommended that you consult an experienced technician. They can diagnose the exact cause of your issue.