How to Add, Change, and Reprogram a Mazda 3 Spare Key Whether you dropped your key fob on the floor or it simply stopped working, it's always best to have an extra key available This article will explain how to add, modify or reprogramme your Mazda 3 keyfobs Certain keys require programming from professional locksmiths, while others do not Use only official Mazda replacements to replace your key fob How to add an extra key You can also add an additional key if you don't have a spare key, or if you accidentally break your existing one To accomplish this, you'll need an inexpensive flathead screwdriver as well as an CR2025 battery that's new Once you've got these items and tools, you're ready to open the key fob Find the key release auxiliary It's located on the bottom of the metal part It's easy to locate The cover that covers the back should come off as soon as you press the button Then, place the screwdriver's head in the notch on top or the space, and pry the metal part off Insert the spare or new key into the slot after removing the auxiliary key Turn on the ignition and wait for about five seconds, then set it to OFF This will register the new key's information to the system, allowing it to start your car in the future It is only possible to program three keys in your Mazda 3 You don't want to have to use more than two keys to start your car This is a safeguard to stop unauthorized users from activating your key fobs and starting your vehicle How to Reprogram a Spare Key If you have a spare key it's a good idea know how to program it if your original key gets lost or stolen This will stop unauthorised people from starting your car, or stealing it This procedure should work with any Mazda however, you'll require two working keys to start the reprogramming If you don't have two working keys, you'll have to take your vehicle to a dealer to get it done Start by getting into the driver's seat and shutting all doors, with the exception of the one that is open Turn the ignition on and insert the first functioning key For five seconds, take the key out and repeat the process with a second working key After you've programmed your new key, you should have three keys that you can use to start your vehicle in the future Before you store each key, make sure it's working properly It's a good idea purchase an extra Mazda 3 key fob, especially if you're someone who often loses your key or has other issues with it You can buy one online or at your local automotive store, but be sure to read reviews before buying so you aren't purchasing one that's not compatible with your car How do you change the battery on a spare key It's depressing to find out that your key fob has died, and you are in a position to not unlock your vehicle It's easy to replace the battery yourself and save money at the dealership The first step is to press the auxiliary key button that is located on the back of the key fob This will remove the metal auxiliary key and expose slots on both sides of the case Use the screwdriver's flathead to push it into one of these slots, and gently pry apart the two sides of the case Once the battery is fully exposed, take it out and put it away somewhere you won't forget it Before you start, make sure that you have a new replacement battery They are available at any store that sells batteries or at an Mazda dealer close to Winter Garden The correct type of battery is crucial to ensure that your keyfob works properly Replace the cap on the battery, and then put in the new battery Be careful not to scratch the small rubber ring the battery is placed on https//wwwthekeylabcouk/mazda-car-keys/ should be pressed together until you can hear the click How to Reset the Keyless Entry System The key fob that you have in your Mazda 3 is not only a convenience, it's also an important security feature The car won't start if the key is lost or stolen even if you have an extra fob The key fob needs to be reprogrammed by a dealer to make it work again It's a difficult and costly ordeal Therefore, it's recommended to learn how to reset the system To reset the system, disconnect the battery for around 15 minutes This will take out any remaining electricity in the on-board computer Then, disconnect both the LF-ECU and demand switch connectors Check for continuity between the terminals Place the key into the slot, then switch the ignition on Put the key in for around five seconds and then turn off The key's details 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 need however only one must be utilized at any certain time This will keep unauthorised individuals from stealing your key and gaining access to your car You can purchase a replacement key fob online, however you'll still have to visit an expert locksmith or dealer to get it cut and programmed