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How To Fix Mazda 3 Key Fob Low Battery Problems

We all rely on our cars these days and have become used to excellent reliability. But what happens when your Mazda 3 key fob low battery warning light comes on?

This shouldn’t be a problem as your car should start at least a few more times before the battery is completely dead. But of course, you need to get the battery changed as soon as possible.

There are two versions of the key fob, one with a key built-in, and the other is keyless. This short article describes how to check the battery is the problem and how to change it in both types.

Mazda 3 Key Fob Battery Low Warning

What happens when the key fob battery is low?

The first indication that your key fob battery is low will be a green indicator on your dashboard. How this is displayed may vary depending on your car’s year, so it may flash or not.

Older cars may not have this indicator. In this case, you will probably notice that you have to stand closer for the remote door unlocking to work.

Mazda 3 key fob battery life

According to Mazda, the key fob battery will last between one to two years, which is quite a short time. This will depend on the type of key fob you have.

If it is a keyless engine start key fob, then the extra drain will account for the short life. Key fobs that only operate the remote access and immobilizer will probably last much longer.

If left within range of the car, the keyless type will remain active and drain the battery. You need to be at least 30 feet from the vehicle for it to deactivate.

Mazda Key Fob Battery Replacement

What battery does a Mazda 3 key fob use?

The Mazda 3 key fob uses very standard coin shape CR type batteries. Fobs with a key use the CR2016, while keyless fobs use the CR2025.

The CR2032 is very similar to the CR2025, but it’s slightly thicker, so you shouldn’t use it.

We recommend that you use a well-known brand such as Duracell or Energizer for the most extended life.

How much does a Mazda 3 battery cost?

The CR type of batteries are very inexpensive, and you can buy a pack of ten for just a few dollars. Hardware stores will be able to sell you an individual battery for less than a dollar.

Step by step instruction of changing Mazda 3 key fob battery

For model 2010-2013 (with CR 1620 battery)

  • Push the button on the fob to flip out the key
  • In the gap where the key usually sits, you will be able to see a small tab.
  • With a small screwdriver or another tool, gently push the tab towards the key.
  • This will split the fob into two parts.
  • Take the part of the fob with the buttons and look at the open end.
  • You’ll see two small tabs to release, and then the fob will split in half, exposing the battery.
  • Replace the battery and reverse the procedure to put the key fob back together

This short video shows you how to change the Mazda 3 key fob battery in a couple of minutes.

For models 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, noting the rubber seal.
  • Replace the battery and reverse the procedure to rebuild the key fob

This short video shows you how to change the Mazda 3 keyless fob battery in just a few minutes.

Mazda 3 Key Fob Battery Keeps Dying After Fitting a New Battery

The first thing to try is to replace the battery again. It’s very uncommon for a new battery to fail right away, but it can happen.

If the battery isn’t the problem, then it’s probably time to speak to a mechanic.

How do you start a Mazda 3 with a dead key?

With the key type fob, you use the key instead of the fob buttons to open the door and start the engine as usual.

For the keyless type, it’s a bit more involved:

  • Flip the key fob over
  • Look 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 troubleshoot Mazda 3 key fob battery keeps dying.

# Your replacement battery is bad

First, replace the battery with another new one. It is rare but possible that there is a problem with the battery. Make sure you are using the correct battery by checking the manual.

If you still have a problem, then there is something wrong with the key fob.

#Your fob is too close to the car

Leaving your key fob too close to the car means it will constantly be active. This can drastically shorten the life of your battery and cause the issues described above.

# Putting your keyfob in your pocket

It is possible that while in your pocket, something can push against the buttons. Again, this will shorten the battery’s life significantly.

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.

# Key fob issue or car issue?

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.

# In case you cannot solve the problem, please consider the following solutions

Solution 1: Have the car dealer fix your problem. This is the quickest option, but the most expensive.

Solution 2: Buy a new key fob from a dealer. If you are 100% confident that the key fob is the problem, you can buy a new one from the dealer and program it yourself.

Solution 3: Buy a new Mazda 3 key fob on eBay/ Amazon. An aftermarket key fob will be up to 10 times cheaper than buying one at the car dealership. You can then program it yourself.

This short video has instructions on programming your Mazda 3 key fob. Bear in mind that keyless fobs will have to be programmed using a computer.


Losing your key fob or the battery dying is inconvenient but not the end of the world. The short article above makes it easy to change the battery or program a replacement Mazda 3 key fob.

In most cases, you can do it yourself without paying a dealer. The only exception is the keyless fob, which needs to be programmed using a computer.

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