How to Fix Mazda 3 Key Fob Low Battery Problems

A key fob is the main device used in keyless entry systems, and it has a radio transmitter that enables it to send signals in code form to the car’s receiver system. That in result, unlocks or locks the doors. A small flat key fob battery usually powers fobs. The key fob battery should be replaced so that to keep the key Fob functional.

Mazda 3 Key Fob low battery isn’t a big problem as your car should continue starting as many times as possible. But obviously, you should change the battery as soon as it dies to make it more effective. Mazda 3 Key takes the CR2025 battery. There are two versions of fobs; the inbuilt one and the keyless Fob. We also have the Fob smart key, which takes battery typeCR2025, the Fob flip, which takes CR1620, and the Fob rectangular, which takes CR2025.

Battery types that Mazda 3 key fob usesFix Mazda 3 Key Fob Low Battery

The Mazda 3 key fob uses CR-type batteries, which are coin-shaped. Key Fobs use the CR2016 battery type, while keyless fobs use the CR2025 battery type.CR2032 and CR2025 are similar, but CR2032 is thicker, so it should not be used at all. The most well-known brands are Duracell and Energizer, which have the most extended life, and they are also recommended.

  • Mazda 3 Key battery life                                      

Mazda 3 key fob batteries usually last between one to two years, short. But it depends on the type of key Fob you use. Keyless engine start key fob takes a shorter life than key fobs that operate the remote and immobilizer. These batteries are likely to last longer. If the Keyless type is left within the car, it remains active and may drain the battery; for it to deactivate, you should be 30 feet away from the car.

  • Mazda 3 key battery costs

 The Mazda CR type of batteries are very cheap, and you can buy as many packages as possible with just a little money. Many stalls usually sell the battery types for less than a dollar, that is, one battery.

  •  Mazda 3 Key fob low battery warning signals

The first and foremost indication that your key fob battery is low will be using a dashboard indicator that usually uses a green light on your dashboard. Different cars display it differently depending on their year of manufacture and some other differences. The light might flash on the dashboard or not.

Tips on how to replace Mazda 3 key fob BatteryTips on how to replace Mazda 3 key fob Battery

1. Replacing models between 2010 and 2012

 It would help if you pushed the button on the Fob to flip or overturn out the key. In the gap where the key usually sits, you will be able to see a small tab. With a small screwdriver, penknife, crimp, or another tool whose work is relevant, gently push the tab towards the key. This will open or split the Fob into two parts.

Take the part of the Fob with the buttons and check at the open end of it. You will see two small tabs to release, and then the Fob will open or split in half hence exposing the battery. Then replace the battery and revert the procedure to put the key Fob back together in its position.

2. Replacing models between 2013-2018 Mazda3 with CR2025 battery

  • On the back of the Key Fob, find the small quick release tab.
  • Push the tab down and remove the spare key hidden inside the Fob
  • In the opening created by removing the key, there are two small slots, one on each side.
  • Using a screwdriver, gently separate the two halves of the Fob by inserting and twisting.
  • Now slide the screwdriver down the side of the Fob and gently rotate to separate the two halves.
  • Remove the battery cover and note the rubber seal.
  • Replace the battery and reverse the procedure to rebuild the key Fob.

How to start a Mazda 3 with a dead key

For the keyless Fob, the procedure usually takes a while.

  • Firstly, flip the key fob overlook for the small tab on the back. 
  • Push the tab and pull the end of the Fob. This will release the spare key that is hidden inside the Fob.
  • Use the key to unlock the driver’s door.
  • Put the key back into the key Fob.
  • Put your foot on the brake.
  • Hold the Mazda symbol on your key Fob against the start button. The engine should start.

How to fix a Mazda 3 key fob battery that keeps dyingHow to fix a Mazda 3 key fob battery that keeps dying

  • Firstly, ensure you replace the Mazda 3 key fob battery with a different new one of the same features as the older one. It is rare but possible that there is a problem with the battery.
  • Make sure you are using the correct accumulator by scrutinizing the instruction book.
  • If you still have a complication, then there is something wrong with the Key Fob.

Leaving your key Fob too nearer to the car means it will constantly be functioning. This can significantly shorten the animation of your battery and cause the complications stated above. It is possible that while in your pocket, something can press against the buttons. Again, this will shorten the battery’s life drastically.

Another problem is sweat and moisture if the Fob is in your pocket for long periods. It’s possible that the moisture could damage the circuit board, causing a short circuit. Some technicians specialize in repairing this type of damage if a replacement cost is too high.

Things to check if the Fob isn’t working;

  • Battery voltage. It should be around 3.2 volts.
  • Metal tabs inside the Fob for the buttons. If they are bent, they may not make proper contact when the buttons are pushed.
  • Do you have a spare key fob? If neither of them works with new batteries fitted, it could be a problem with the car.

 Tips to follow if you are unable to solve the problem Tips to follow if you are unable to solve the problem

Solution 1:

It would help if you had the car dealer fix your problem, which tends to be the quickest option, but the most expensive.

Solution 2:

 It would help if you bought a new Mazda 3 key fob from a dealer. If you are sure that the Key Fob is the problem, you can buy a new one from the seller and program it yourself.

Solution 3:  

You can also buy a new Mazda 3 key fob on E-marketing platforms like eBay and Amazon. An aftermarket key fob will be up to 10 times cheaper than buying one from or at the car dealership. You can then program it by yourself.

Solution 4:

Check the owner instruction manual to see if the automaker installed a backup solution for starting the car if the key dies.

Solution 5:

Press the start button with the key itself. Some cars can still detect dead key fobs this way in emergencies or when they fail.


Losing your Mazda 3 key fob or the fob battery dying is inconvenient, but not this does not mean that everything else has to stop. You can replace it, and the issue gets resolved. With the above procedures, you can have it replaced without challenges.

In most cases, you can do it yourself without paying a dealer. The only thing that might distract you from replacing is if you don’t have such skills. Failure to understand the basics in doing a replacement might also affect the process. Follow the above tips, and you will have your Mazda 3 Key replaced in a few minutes.

here is a video showing how to open up the new Mazda 3 key FOB to change the battery. It carries a 2032 battery.

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