How To Change a Key Fob Battery

How To Change a Key Fob Battery

Key fobs are very convenient—until the battery dies. However, although it may seem like a hassle, changing the battery in a key fob is easy and can be done in just a few minutes. Read on for step-by-step instructions on how to change a key fob battery.

How to change the battery in a key fob

A dead key fob doesn’t have to turn your car into an expensive paperweight. Thankfully, changing a key fob battery is easy. However, you need a few things before you get started:

  • A new key fob battery, which you can usually find at your local hardware store or online
  • A small flathead screwdriver
  • A coin or another flat object

Locate your spare fob

It’s typical for cars to have at least two key fobs, and you may have a spare in your desk, bedroom or kitchen drawer. For a quick solution, locate the spare fob, and you can go buy new batteries. If you don’t have one, you may want to consider getting a replacement.

Identify and procure the correct battery type

In most key fobs, the battery is called a button or coin cell battery because of its shape and size. The identification number is etched into the flat side of the battery. This ID number is three to four digits long, and the new battery must have the same number. The battery most commonly used in key fobs is the CR2032 battery, but other widely used button batteries include the CR2450, CR2025, CR1616 and CR2016.

Split open the fob

Because smart keys can take many forms, the first recommendation would be to read the owner’s manual section that explains key fob battery replacement. If you don’t have a manual, many key fobs can be opened using a flathead screwdriver or coin inserted in a notch to pry open the fob. If your key fob has a backup key, remove the key and you may see a notch. Insert your flathead screwdriver into the gap and twist. The key fob will split open at the seams with very little force.

Locate and replace the battery

Once the key fob is open, you should see the battery inside. It may be held in place by a small metal tab. Use your fingers to carefully lift the battery and replace it with the same positive and negative orientation.

Replace the fob and test it

After installing the battery, snap the fob back together, replace your backup key and test out the new battery. If it unlocks and starts your car, the fob is still synched.

Does my fob need to be reprogrammed after replacing the battery?

In general, you do not have to reprogram the key fob. It should still be synched. If you replace the battery and the fob still won’t unlock the doors or start the car, it may need to be reprogrammed. You need to either schedule an appointment at a dealer and use your spare fob to drive there, or call an automotive locksmith who can come to you.


Changing a key fob battery is easy and does not require special tools or mechanical know-how. If your key fob isn’t working after changing the battery, another issue may be at play. In this case, consult your dealer. They can help diagnose the problem and get you back on the road in no time.

Frequently Asked Questions

Can I drive my car with a dead key fob?

If your battery dies while driving, you won't have a problem. If you need to open and start your car and your key fob has a backup key, use the key to open the door. Once inside, place the key fob on or near the start button, key slot or other designated area. Then, while pressing the brake, push the start button.

How long should car key fob batteries last?

Typically, a car fob battery should last between three and four years.

How much does it cost to replace the key fob battery?

A four-pack of typical key fob C2032 batteries can cost less than eight dollars.

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Disclaimer: The above is solely intended for informational purposes and in no way constitutes legal advice or specific recommendations.