How to Add, Change, and Reprogram a Mazda 3 Spare Key It's a good idea to keep an extra key at hand, whether you dropped the keyfob you were using or it has stopped working This article will explain everything you must know about the process of adding, changing, and changing the programming of your Mazda 3 key fobs A word of caution Certain keys need to be programmed by a professional locksmith or dealer, whereas others do not Use only genuine Mazda replacements to replace your key fob How do I add an additional 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 To accomplish this, you'll need a small screwdriver with a flat head and an updated CR2025 battery Once you've got all the equipment and tools, you're ready to open the key fob Find the auxiliary key release It's located on the underside of the metal portion and is easy to find The cover on the back should fall off the moment you press the button Then, put the screwdriver head into the notch on top or in the space, and remove the metal part Once the auxiliary key is removed, insert the new or spare key into the slot Switch the ignition on and then wait for around five seconds, and then turn it to off This will allow the system to recognize the new key and begin your vehicle in the future You can only program three keys to your Mazda 3 The final thing you want is to have more than two functioning key fobs, and not be in a position to get your car started This is a safety measure to prevent unauthorized users from activating your key fobs and starting your car How do I reprogram an unrepaired key It's a smart idea be aware of how to reprogram an extra key in the event that your original key gets lost or stolen This will stop unauthorized persons from getting into your car and causing damage to it This should work with any Mazda You'll need two keys that are working to begin the reprogramming If you don't own two keys that function then it's best to bring your Mazda to a dealer to get this done Start by stepping into driver's position and shutting all doors, with the exception of the one that is open Put the first working key into the slot, then turn the ignition to ON After five seconds, remove the key Repeat with the second key Once you've finished programming your new key, you'll have three keys that you can use to start your vehicle in the future Test https//wwwthekeylabcouk/mazda-car-keys/ to ensure sure they're working correctly before placing them away You should think about buying a spare Mazda 3 remote, especially in the event that your vehicle is prone to problems You can purchase one online or at your local automobile store, but be sure to read the reviews before purchasing so that you can avoid purchasing a key fob that's not compatible with your vehicle How do I change the battery on a spare key There's nothing more frustrating than finding that your key fob battery has died and you can't unlock your car It's easy to change the battery yourself and save money at the dealer Press the auxiliary key button located at the back of the keyfob This will detach the key made of metal and reveal two slots on the opposite side of the case Place the flathead in one of these slots and then gently pry the two halves of the case apart When the battery is fully exposed, take it out of the case and place it in a place where you won't forget about it Before you begin, be sure you have a new replacement battery They can be bought at any store selling batteries or from a Mazda dealer in Winter Garden Using the correct type of battery will ensure that your key fob is working effectively Replace the battery cap and then install the new battery Be careful not to damage the rubber ring that holds the battery Finally press the two parts of the key fob together until you hear an audible click How to Reset a Keyless Entry System The key fob in your Mazda 3 is not only an option for convenience, it's an important security feature The car won't start if your key is stolen or lost, even if you've got an extra fob The key fob has to be reprogrammed by a dealer to make it work again It can be a frustrating and costly ordeal Therefore, it's best to know how to reset the system Remove the battery from the system for 15 minutes This will clear any residual power from the on-board computer Then, disconnect the LF ECU and demand switch connectors Check for continuity between the terminals To program a new key, or a spare, place it in the slot and turn the ignition to ON The key should remain in the ignition for about five seconds and then switch it off The key's information will be transferred to your vehicle's computer and the new fob will be able start your car in the future You can program as many fobs as would like, but only one should be used at a given time This will prevent unauthorized persons from copying your key and gaining access to your car You can buy a new keyfob from the internet, however it must be programmed and cut by an authorized dealer