How To Change a Car Key Battery

Has your car key fob stopped remotely opening your doors? Or does it only unlock the doors some of the time, but not all of the time? This might mean that it’s time to change your car key battery.

In this post we’ll tell you how to replace your car key battery. But first, it’s important to ensure that you are indeed having a problem with your car keys, and that you’re not facing a different underlying problem.

Is It My Car Keys, or Is It My Battery?

If the remote locking on your car key fob isn’t working like it should, then it might be a sign that there’s something wrong with the battery in your car key fob. Or, it might mean that there’s a problem with some other aspect of your car.

Here are some ways you can narrow down the issue:

  • First, try opening your car doors the old-fashioned way – by manually unlocking the doors. If you find you can’t do this, then you may have an issue with the locking mechanism of your car, rather than with your key fob.
  • Next, try starting your car. Does the engine start readily, with just one turn of the key or push of the start button? Or does it only start after a few seconds, or a few tries? If so, there may be an issue with your car’s battery.
  • Did something recently trigger the car alarm, whether it was an accident or an attempted break in? If so, the security system may have disabled remote entry as a safety precaution. The car manual should tell you how to reset the security system.
  • Finally, if you have multiple key fobs for your car, see how you get on with a different fob. If it works without a problem, then you most probably have an issue with the battery of the standard fob.

So you’ve narrowed down the problem, and you’re pretty sure it’s an issue with your car key fob battery. So how do you change the battery? And what sort of battery does your key fob need?

How To Change a Car Key Battery

First, you need to open your car key fob. How you do this will depend on what type of car you drive. For some fobs, you can simply use your fingernails. But you might need to use the car key itself or a screwdriver to gently prise open your fob. And on some fobs, you may need to undo some small screws first.

Once you’ve opened your fob, you should see the battery immediately.

car key battery

What Sort of Battery Do Car Key Fobs Take?

Batteries used in key fobs are usually small, round, silver batteries, that resemble a coin. It’s small, round, silver, and resembles a coin. Take out the battery and look for a code, and a voltage. The code will start with two letters (such as CR), and the voltage should be written below the code (e.g., 3V).

Where to Buy Replacement Car Key Batteries

You can buy replacement batteries at most supermarkets or you can buy them online on websites like Amazon. Just make sure that the replacement you order matches the code and the voltage on the battery you’re replacing. If your replacement battery is too weak, it won’t work like it should. And if it’s too powerful, it could leak, which would permanently damage your fob.

Once you have your replacement battery, simply put it back in your fob, then clip your fob back together. Your car keys should then work like they used to. If they don’t then you may have bought the wrong type of battery, or there’s something else wrong with your car. Take a look at the steps we suggested above to try and narrow down the problem once again or consider booking your car in for a service.

Does Car Insurance Cover Car Keys?

By now, it should be clear that changing the battery in your key fob is a straightforward process that you can do from home.

However, we can give you comprehensive Key Cover as an optional extra on our comprehensive car insurance policies if you are worried about losing or damaging your keys, or if you think they’ve been stolen, we’ll cover you for replacements, for locksmith charges, and for any repairs your locks might need.

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