How to Add, Change, and Reprogram a Mazda 3 Spare Key It's a good idea to keep an extra key at hand no matter if you've dropped the keyfob or it has stopped working This article will show you how to add, alter, and reprogramme your Mazda 3 keyfobs Warning Some keys require programming from a professional locksmith, while others do not Only use official Mazda replacements to replace your key fob How to Add a Spare Key You can also add another key in the event that you don't have a spare key, or when you accidentally damage your existing one You'll need to use an flat-head screwdriver and a CR2025 new battery Once you have these items and are ready to open up the key fob and replace the battery Locate the auxiliary key release It's on the underside of the metal portion and is easy to locate The cover on the back should fall off when you press the button Then, put the screwdriver head into the notch at the top or the space, and pull the metal piece off Insert your new or spare key into the slot after taking out the auxiliary key Turn the ignition on and then wait for around five seconds, then turn it to OFF This will allow the system to recognize the new key and start your vehicle in the future https//wwwthekeylabcouk/mazda-car-keys/ is important to remember that you can only program up to three keys for your Mazda 3 You don't want to have to utilize more than two key fobs in order to start your car This is a safety measure to prevent unauthorized users from activating your keys and starting your car How to Reprogram a spare key If you have a spare key it's a good idea be aware of how to program it in the event your original key is stolen or lost This will stop unauthorised people from stealing your car and starting it This will work with any Mazda You will require two keys that are working to begin the reprogramming process If you don't have two functioning keys, you'll need bring your vehicle to the dealership to complete the process Begin by stepping into your driver's seat and close the door, with the exception for the one that's been opened Put the first working key in the slot, then turn the ignition to the ON position Wait five seconds before removing the key Repeat the process with the second key Once you've completed programming your new key, you should have three keys that will work to start your car in the near future Before saving each key, be sure that it's working correctly It's a good idea to purchase a spare Mazda 3 key fob, especially if you're someone who often loses your key or has other issues with it You can purchase one on the internet or at a local automotive store Make sure you review the reviews before buying to ensure that you don't purchase the wrong key fob that isn't compatible with your vehicle How do I change the battery on a spare key There's nothing worse than finding that the battery for your key fob has been damaged and you're unable to unlock your vehicle Luckily, it's easy to replace the battery and save yourself some money at the dealership The first step is to press the auxiliary button on the back of the key fob This will release the metal key and reveal two slots on the opposite side of the case Put the flathead into one of these slots and then gently pull the two halves of the case apart After the battery is fully exposed, take it out of the case and put it somewhere you will not forget about it Be sure to have an additional battery prior to beginning These batteries can be purchased at any store that sells batteries or from a Mazda dealer in Winter Garden Choosing the right battery will ensure that your key fob works properly Replace the cap on the battery and then insert the new battery Be careful not to scratch the small rubber ring the battery is placed on The two halves should be pressed together until you hear the click How can I reset the Keyless Entry System The Mazda 3 key fob is not just a convenience It's also a security measure If you lose your key or have it stolen the car will not start, even if you have the spare key fob This is because the fob that you have to be reprogrammed at the dealership in order to work once more It can be a costly and time-consuming process, so it's a good idea to know how to reset the system yourself To reset the system, unplug the battery for 15 minutes This will remove any residual electricity in the on-board computer Then, disconnect both LF-ECU and demand switch connectors After that, test for continuity between the following terminals To program the new key or spare, insert it into the slot and turn the ignition to ON Leave the key in for around five seconds and then switch it off The key's information has been transferred to the computer of your vehicle and the new fob is able to start your vehicle You can program up to three fobs however, you must only use one at a time This will stop unauthorised people from copying the key and gaining access to your car You can purchase a brand new key fob on the internet, but you'll still have to visit a dealer or locksmith to get it cut and programmed