Car Key Battery Replacement

When your car key begins to malfunction or not work as it should, it’s not often the fault of the fob but the car key battery itself. Replacing the batteries is a relatively straightforward task that costs very little and takes just minutes to do.

Tweet Pin It
Car Key Battery Replacement
YourCar is reader-supported. When you buy through links on our site, we may earn an affiliate commission. Find out more.

Replacing the batteries in your car key is a fairly common procedure and something that you can easily do yourself. Rather than getting your dealer to change it for you, you can save yourself a sizable amount by doing it yourself.

Symptoms of Faulty Car Key Batteries

The main and most common symptom of a failing car key battery is the central locking not working from a normal distance. If you are needing to go right next to the door to unlock the car, this is a clear sign of the battery becoming weak. General inconsistency of the key fob is another sign and this can become clear when the key works fine during the day but malfunctions on a cold winter morning or night.

What Batteries Do Car Keys Use?

As you can imagine, all car keys are different and require a particular size battery. Some of the popular car key batteries include CR2032, CR2025 and many others but a quick online search or looking at your car’s manual will give you a definitive answer. Considering the small cost of the batteries, we highly recommend buying them in bulk. The last thing you want to happen is being unable to get your hands on the batteries when the car key battery next needs replacing.

How To Replace a Car Key Battery

Depending upon your particular key fob will determine the best method of replacing the battery. However, the majority follow a similar method of replacement, which is as followed:

  1. Pry the fob open using the valet key or screwdriver.
  2. Lift out the circuit board (if batteries aren’t accessible).
  3. Pull out the existing batteries.
  4. Replace with new batteries (ensure positive is showing).
  5. Place the circuit board back into the fob.
  6. Ensure the fob is fully secured.

How To Replace a Car Key Battery

Problems That May Arise

Although relatively straightforward, there may be some problems you come across as you replace your car key battery. The first being that the replacement batteries simply don’t work as they should. Nine times out of ten, this is due to the incorrect positioning of the battery. Most require the positive side of the battery to be showing (as above).

Another issue that may arise is that you simply cannot remove the circuit board or gain access to batteries. It’s important to note that you shouldn’t have to use excessive force gain access to the batteries and if you are, you are probably doing it wrong. If this is the case, we strongly recommend looking at enthusiasts forums or YouTube videos for tutorials of removing the batteries of your particular key fob.


Car keys are progressively getting more complex and require frequent battery replacement for optimum performance. Learning how to change the car key batteries yourself is highly advised because in the long run, it will save you a fortune. To avoid disappointment, ensure that you use the correct battery for the fob. Although the incorrect size may fit into the fob, it may be too powerful or weak, which could cause the key to malfunction even further.

Follow #YourCarUK

Copyright © 2024. All rights reserved.