Changing the Battery in Your Mazda 3 Key Fob

There is nothing more frustrating than returning to your car after a long day, and discovering that your key fob battery is dead. This is a straightforward fix that is easily done at a major box retailer or hardware store.

A spare key fob for your Mazda 3 is an inexpensive alternative to not having to take it to a dealership in order to have them reprogram the keys.

Battery Replacement

You can replace the battery on your Mazda 3 keyfob at home. However, you should only replace the battery when it dies, or if the key fob shows a message on the multi-information display stating, "Low key fob battery. Replace battery."

You'll need a flathead screwdriver with tape and patience to open the case. Locate a notch or gap in the bottom metal part of your Mazda 3's key fob and insert the head of the screwdriver to pry off the lower half. Repeat the procedure for the top piece of metal, but be sure not to scratch the rubber ring at the bottom of the case.

You'll find a slot on each side of the fob case, which houses the battery. Use the flathead screwdriver with tape to gently the case open, starting on one side and then moving to the next. Remove the old battery and put in the new CR2025 and make sure it's in the right orientation for proper orientation. Then, put the cap back on and reattach both sides to the key fob's case, pressing until you hear them click.

After replacing the battery Lock and unlock your doors to confirm that the fob is working. If everything looks good then you can begin using your mazda replacement keys 3's remote features on the road again!

Pairing Issues

This could mean that the transmitter inside your car has been damaged. It is usually a job to a professional and you will require a new key fob.

If you've tried replacing the battery and reprogramming the key fob but did not resolve the issue, it is possible that the chip in the key fob might be defective. This can happen if your keyfob was dropped or exposed to saltwater or the touch of dirty fingers.

To diagnose this issue it is necessary to locate a small "key" that is embedded into the seam of the fob that lets you lift it open and take out the circuit board. Then, you can examine the chip for corrosion or damage. It is best to use a clean paper towel to avoid damaging the microchip.

It is also possible to inspect the battery connector's terminals to determine if they're damaged or cracked. If this is the situation then resoldering the terminals into place can usually restore the functionality of the key fob. Additionally, you can look at the buttons to determine whether they're worn or damaged. If the buttons are loose they can be resoldered to their original position unless they have physically snapped.

Interference Signals

Few things are more annoying than staring at the "No Fob Detected" message when trying to start your vehicle. This can happen at the most inconvenient occasions, such as when you're running late to work or have to pick up your children from daycare or school. The good news is that there are steps you can take to investigate the issue and determine what is causing it.

Interference signals can disrupt the remote key fob signal coming from the vehicle and cause it to not function properly. This could be caused by things like buildings, weather conditions and transmitters that use the same frequency. Interference can also occur if you have aftermarket equipment installed in your vehicle that transmits on the same frequency as the key fob.

In addition, if your key fob is exposed to salt or waters, it could be damaged. The rubber seals on the chip's electronic components can be penetrated by water, particularly in the event that it is submerged for an extended period of time like in a pool or ocean at the beach. The chip can stop working and require replacement of the keyfob. If you have a key that is able to be programmed, you can clean it using isopropyl or electronic cleaners to restore its function. If this does nothing you can be sure that the chip has fried and needs to be replaced.

Locking/Unlocking of the Doors

The buttons on the fob's key send electronic signals to the solenoid of the car, which then converts the signal into mechanical action. It locks and unlocks doors. If the door lock isn't working, it could be a solenoid issue that requires some investigation with the assistance of an expert auto repair shop.

A dead 12 volt battery can also prevent the fob from functioning correctly. This is the case if the battery loses its charge, or if the contacts become corroded and stop conducting electricity. The problem can be addressed in just a few minutes by purchasing a new battery.

If the key fob doesn't work after changing the battery or program it again, the issue might be in the receiver module. The device detects radio frequency signals sent by the key fob to control the vehicle. If it malfunctions it could be costly to fix.

To determine if this is correct, place your spare key into the key slot. Then turn the ignition on. Press the key fob two times for 10 seconds without removing it. The Mazda 3 system will now be able to synchronize the key with your car and you can use it as your primary remote for driving. You can program up to three keys in this manner.