How to Replace a Dead Coin Battery in Your replacement jaguar key fob XF The Jaguar Smart Key allows you to lock and unlock your jaguar key locksmith - please click the next post, quickly. It also has security features, including the ability "double lock" your vehicle to stop thieves from breaking windows to gain entry. However, there are many reasons why your Jaguar XF key fob might not work. This could be due to a dead coin battery, signal interference, and a malfunctioning electronic chip. Dead coin battery Modern electronic keys offer greater convenience and security than manual keys. They can lock and unlock your vehicle, turn on the lights and start the engine. They also have additional features that make driving more convenient. They are prone to losing their battery over time. If you've noticed that the key fob of your Jaguar XF isn't working it could be due to a dead coin battery. The good news is that replacing it is a simple and easy fix.