Changing the Battery in Your Mazda 3 Key Fob There is nothing more frustrating than getting in your car after a long day, and realizing that the key fob battery is dead Fortunately, it is simple to fix it with the simple replacement of a battery at an hardware store or a big box retailer A spare key fob for your Mazda 3 is an inexpensive way to avoid having to take your vehicle by a dealership to let them reprogram the keys Battery Replacement Removing the battery from the Mazda 3 key fob is an easy process that can do at home But, you should only replace the battery if it is dead, or if the key fob displays a message in the multi-information display saying, "Low key fob battery Replace battery" You'll need a flathead screwdriver and tape and patience to open the case https//wwwthekeylabcouk/mazda-car-keys/ into a notch, or gap, on the bottom metal of the Mazda 3 key fob to take off the lower portion Repeat the process for the top part of the metal but be careful not to damage the rubber ring on the bottom of the key fob's case You'll find a slot on each side of the fob case that houses the battery Make use of the tape-wrapped flathead screwdriver to gently pry open the case, starting on one side before moving to the opposite Remove the old CR2025 and replace it with a brand new one, ensuring that you put it on its face to ensure proper the polarity Finally, place the battery cap back on and reconnect both sides of the key fob's case Continue pressing until you hear them click Now that you've replaced the battery check the fob to verify that it functions by locking and unlocking your doors If everything is in order then you're able to use your Mazda 3's remote capabilities for the first time Pairing Issues This could mean that the transmitter in your car may have been damaged This typically requires an expert to repair it and may require a new replacement key fob If you have tried replacing the battery and reprogramming the key fob, but this did not resolve the issue, it is possible that the chip in the key fob might be faulty This can happen if the keyfob has been dropped, exposed to saltwater, or was touched by dirty fingers To identify the issue it is necessary to locate a tiny "key" embedded in the fob's seam that lets you lift it open and take out the circuit board You will then be able to look for any damage or corrosion on the chip To avoid damaging the chip, it's recommended to clean the chip with a new paper towel You may also take a closer look at the battery connector's terminals to check if they're cracked or broken If this is the situation it is possible to solder the terminals back into place will typically restore the functionality of the key fob Additionally, you can look at the buttons to see if they are worn or damaged If the buttons are loose, they can easily be re-soldered as well unless the button is physically snapped off Interference Signals There are few things more frustrating than trying to start your car and then seeing the message "No Fob Detected" It happens at the worst time, for instance when you're running late to work or pick up your children from daycare or school The good thing is that there are a few steps you can take to investigate the issue and figure out the cause Interference signals can disrupt the remote key fob's signal to the vehicle, causing it to not function correctly This could be caused by things such as buildings, weather conditions and transmitters that operate on the same frequency Interference can occur when your vehicle has aftermarket equipment that transmits at the same frequency as your key fob Additionally, if the key fob is exposed to salt or water the water, it might be damaged Water can damage the rubber seals of the electronic chip especially when the key fob has been submerged in water for a prolonged duration This can cause the chip to cease working and require replacement of the key fob If you have a key that can be programmed, you can clean it with isopropyl or electronic cleaners to restore its functionality If this does not work, the chip is likely fried and will need to be replaced Locking/Unlocking the Doors The buttons on the key fob send electronic signals to the solenoid inside the car, which converts this signal into mechanical action This locks and unlocks doors If your door lock isn't working it could be because of an issue with the solenoid This will require experts from repair shops to analyze A dead 12 volt battery could also stop the fob from working effectively This can happen when your battery loses its charge or if your contacts get corroded This issue can be solved in a matter of minutes by replacing the battery If the key fob won't work after you replace the battery or re-program it the issue could be related to the receiver module This device interprets radio frequency signals received by the key fob to control the vehicle If it malfunctions it could cost a lot to fix To determine if this is true, insert your spare key into the key slot Then, turn the ignition ON Press the key fob twice within 10 seconds without taking it The Mazda 3 system synchronizes the key with the vehicle and you can use it as your primary remote for driving You can program up to three keys in this way