How to Add, Change, and Reprogram a Mazda 3 Spare Key If you've dropped your key fob on the floor or it just stopped working, it's an excellent idea to keep an extra key in your pocket This article will show you how to add, alter and re-programme your Mazda 3 keyfobs Warning Some keys require programming by an experienced locksmith, whereas others do not Be sure to only use genuine Mazda replacements for your key fob How do I add a spare key You can also add an additional key if you don't have a spare key or in the event that you break the one you already have You'll need an flat-head screwdriver and an CR2025 battery Once you've got the tools and are ready to open the key fob and swap the battery Find the auxiliary key release The button is located on the underside the metal part It's easy to locate When you hit the button, the back cover should be removed immediately Then, insert the screwdriver's head into the notch at the top or into the space and take the metal part away Insert your new or spare key into the slot following the removal of the accessory key Set the ignition to ON and wait for around five seconds before turning it to off This will register the new key's information into the system, allowing it to start your vehicle in the future It's important to note that you can only program up to three keys for your Mazda 3 The final thing you want is to have more than two functioning key fobs, and not be capable of getting your vehicle started This is a safeguard to stop unauthorized users from activating your keys 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 in the event your original key is stolen or lost This will stop unauthorized persons from getting into your car and causing damage to it https//wwwthekeylabcouk/mazda-car-keys/ is compatible with any Mazda, though you'll need two working keys to start the reprogramming If you don't have two keys that function, you should take your car to a dealer to get this done Start by getting into the driver's position, and close all the doors with the exception of the one that is open Turn the ignition on and insert the initial working key Wait five seconds, then remove the key and repeat the process with a second key After you finish programming your new key you should have 3 keys that will work to start your car in the future Before storing each key, make sure it's working properly You should think about purchasing an extra Mazda 3 remote, especially when your car is susceptible to problems You can buy one online or in your local auto store Make sure to read reviews before purchasing so that you don't get one that's not compatible with your car How do I change the battery with a spare key There's nothing worse than finding that the battery on your key fob failed and you are unable to unlock your car It's simple to replace the battery yourself and save money at the dealer Press the auxiliary button on the back of the keyfob This will take out the metal key that is used as an auxiliary key, and expose an opening on both sides 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 completely exposed, remove it and set aside the case somewhere safe from being lost Be sure to have an additional battery before you start You can purchase them in any store that sells batteries or at an Mazda dealer close to Winter Garden The right kind of battery is crucial to ensure that your keyfob is working properly Replace the cap of the battery and then put in the new battery Be careful not to scratch the rubber ring that holds the battery Then, press the two parts of the key fob together until you hear the sound of a click How can I reset the Keyless Entry System The Mazda 3 key fob is not just a practical feature It also serves as a security feature If you lose your key, or have it stolen the car will not start, even if you have the spare fob The key fob has to be reprogrammed by a dealer to make it work again It can be a stressful and expensive ordeal Therefore, it's recommended to know how to reset the system Remove the battery from the system for 15 minutes This will eliminate any remaining electricity in the on-board computer Then, disconnect both the LF-ECU connector and the demand switch connectors Check for continuity between the terminals Put the key in the slot, and switch on the ignition Turn off the ignition after about five seconds The information from the key 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 want however only one must be used at any certain time This prevents unauthorized people from copying the key and getting ahold of your car You can purchase a replacement key fob online, but you'll still have to visit a locksmith or dealer in order to have it cut and programmed