How to Change the Battery in Your Car’s Key Fob? Step-by-step

how to change battery in key fob

Is the keyless entry system on your car not working? If the latter is the case, this post will show you how to change the battery in your car’s key fob.

In newer cars, the key fob is either a separate piece of equipment that you hang on your keychain and has buttons to lock and unlock your car, or it is a part of the key itself. These keychains are battery-operated and send a wireless signal to your car to control it.

Although batteries can last for two to five years or longer, if the battery in the key fob is low, you might not be able to start the car remotely or get inside.

The good news is that changing the battery in a key fob is straightforward. Here’s a step-by-step tutorial for changing the battery in your key fob.

How to Change the Battery in Your Car’s Key Fob?

You can change the battery in your key fob by following these steps:

Look for the Battery Type Embossed in the Plastic

The type of battery will be printed outside on some key fobs. By doing this, you can choose your battery before having to open the key fob and go to the store. Panasonic, Energizer, and Duracell are three of the most well-known brands of key fob batteries.

Look for the Seam Where the Halves of the Fob Come Together

how to change battery in key fob

The majority of key fobs open by snapping together two halves in a clamshell fashion. There will be a seam where you can separate the two halves; occasionally, there may even be a notch there.

If your car still requires you to insert the key into the ignition switch, be careful not to hang anything else from the keyring than the fob. The weight of your house keys could cause the ignition cylinder to wear out, which could be dangerous.

Gently Pry at the Seam Or Notch

You will only require one tool to change the battery in your key fob. To gently pry apart the two halves and open the fob down the middle, use a small, thin, flat-bladed screwdriver (or, occasionally, a sturdy fingernail).

The majority of vehicles with key fobs and transponder keys won’t let you lock your keys inside the vehicle, but you should be ready in case the worst-case scenario occurs. (By the way, this key finder can be useful if you frequently misplace your keys.

Look at the Battery Orientation (Positive and Negative Ends)

The battery will typically look like a small coin, be labeled with the battery size, and have a plus and minus sign. Keep a close eye on the battery’s orientation. A replacement battery of the same size must be purchased and installed in the same manner.

Pop the Old Battery Out and Place the New Battery In

If you’re having trouble, that flat-bladed screwdriver will help. Usually, the battery will pop out of its place with the press of a finger. Place the new battery in with the plus and minus signs facing in the same directions.

Snap Your Key Fob Shut and Test the Fob Function

The opposite of disassembly is assembly, so snap the fob back together and test the buttons. Everything ought to be like new!

Here is a YouTube video to help you understand the process of changing your car’s key fob:

Do I Need to Reprogram the Key Fob After Changing the Battery?

Typically, you do not need to reprogram the key fob after changing the battery. However, if you’ve changed not only the batteries but also some of the internal wiring and electronics, you might need to reprogram it by re-pairing it with your car.

The usual sequence for reprogramming your car battery is as follows:

  • Put the key into the ignition.
  • Turn the key to the ON position, which turns on the gauges and screens but not the ignition, and then turn it back to the LOCK position.
  • Do this several times until you hear a chiming sound (or some other sound indicating a reset).
  • You can reprogram your key fob by pressing the lock and unlock buttons on it. By doing this, you should make sure that the right settings are saved and that the car will respond the next time you use it.

What Happens When the Key Fob Battery is Low?

Typically, a key fob with a low battery starts exhibiting some or all of the following symptoms:

how to change battery in key fob
  • With time, the fob may start to respond less or not at all.
  • It might be difficult to lock or unlock your car and start losing range. To use the keyless entry feature, you might need to get closer.
  • In vehicles with push-button starts, a weak battery may prevent the vehicle from recognizing a key fob.

Can You Unlock Your Car With a Dead Key Fob?

Yes! Having a dead battery in your car key fob does not mean that you are left stranded. Automakers have included fail-safes to ensure that you can unlock your car even in this situation because they were aware of this scenario.

Here’s what you should do:

  • The mechanical key is a standard feature of all automobile manufacturers. This can be reached by sliding or pressing a tiny button that is typically found on the side of the key fob and removing the fob cover.
  • In order to unlock or lock your car, insert the mechanical key into the key slot after removing it from the key fob.

All major automakers, including Honda, Kia, Toyota, Mercedes, Ford, etc., typically include mechanical keys in their key fobs.


How Much Does a Key Fob Battery Cost?

A button-cell battery pack can cost you between $2-5 depending on the brand and number of batteries you buy. For instance, a Panasonic pack of four costs $3.75 while a pack of two Energizers costs $2.

What Kind of Battery Does My Key Fob Take?

The CR2032 is the button cell that is most frequently utilized in key fobs. The CR2450, CR2025, CR1616, and CR2016 are additional commonly used button cells.

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