How to Add, Change, and Reprogram a Mazda 3 Spare Key It's a good idea always to have an extra key at hand no matter if you've dropped the keyfob you were using or it stopped working This article will teach you how to add, modify or reprogramme the Mazda 3 keyfobs Note Some keys require programming from a professional locksmith, while others don't Use only genuine Mazda replacements to replace your key fob How do I add a spare key You can also add an additional key in case you don't have a spare key, or in the event that you break the one you already have To do this, you'll need an incredibly small screwdriver, a flathead screwdriver, and an updated CR2025 battery Once you've got the tools and tools, you're ready to open the key fob First look for the key release button for the auxiliary key It's on the underside of the metal part and is easy to locate The back cover should slide off as soon as you press the button Then, insert the screwdriver's head into the notch on top or the space and pry the metal part off Once the auxiliary key has been removed, insert the new or spare key into the slot Set the ignition to ON, and wait for about five seconds before setting it to off This will allow the system to recognize the new key and begin your vehicle in the future It is important to remember that you can only program up to three keys on your Mazda 3 You don't want to have to utilize more than two key fobs to start your vehicle This is a security measure to stop unauthorized users from activating your keys and starting your vehicle How to reprogram a spare key It's a smart idea know how you can reprogram an extra key in the event that your original key is lost or stolen This will stop unauthorized persons from starting your car, or stealing it This should work with any Mazda You will require two keys that work to begin the reprogramming process If you don't have two working keys, you'll need to bring your vehicle to the dealership to complete the process Begin by getting into your driver's seat and shutting the door, excluding for the one that's open Turn the ignition on and insert the first functioning key Take five seconds before removing the key Repeat with the second key Once you've finished programming your new key, you should have three keys that you can use to start your vehicle in the future Before saving each key, be sure it's working properly It's a good idea to purchase an extra Mazda 3 key fob, particularly if you're a driver who frequently loses their key or has other issues with it You can buy one online or at a local automotive store Be sure to read reviews before purchasing so that you don't get the wrong key fob that isn't compatible with your vehicle How do I change the battery on a spare Key It's a nightmare to discover that your key fob is dead and you're unable to unlock your vehicle It's easy to replace the battery yourself and save money at the dealer The first step is to press the auxiliary key button on the back of the key fob This will take out the key made of metal and reveal an opening on each side of the case Use the screwdriver's flathead to push it into one of these slots, and gently break the two sides of the case When the battery is fully exposed, remove the case and place it somewhere that you will not forget it Before you begin, be sure that you have a brand new replacement battery They can be bought from any store that sells batteries or from a Mazda dealer in Winter Garden The right type of battery is crucial to ensure that your keyfob is working properly Then, place the new battery in the correct place and replace the battery cap Be careful not to scratch the rubber ring on which the battery rests Then press the two parts of the key fob until you hear the sound of a click How do I reset the Keyless Entry System The key fob inside your Mazda 3 is not only an extra convenience, but also an important security feature The car will not start if your key is lost or stolen, even if you've got an extra key fob The key fob should be reprogrammed by the dealer to allow it to work again This can be a costly and frustrating ordeal and it's a good idea to know how to reset the system yourself To reset the system, remove the battery for approximately 15 minutes https//wwwthekeylabcouk/mazda-car-keys/ will take out any remaining electricity from the onboard computer Next, disconnect the LF-ECU and demand switch connectors Check for continuity between the terminals To program a new key or a spare, insert it into the slot and turn the ignition to ON Keep the key in place for about five seconds, then switch off The information from the key will be added to your vehicle's computer and the new fob will be able to start your vehicle in the future You can program as many fobs you want, but only one should be utilized at any certain time This will prevent unauthorized people from stealing your key and getting access to your car You can buy a new key fob on the internet, but you'll still need to visit an authorized locksmith or dealer to get it cut and programmed