How To Change The Battery In A Mercedes Key Fob

Are the doors of your Mercedes failing to unlock or lock? That means that the key battery is out of juice. When it comes to the key fob batteries of a Mercedes, you should never undermine the low battery signs. By doing so, you may end up locked out of your car. Luckily, replacing the key battery is easy and can take only a few minutes.

So, how can I change the battery in a Mercedes key fob? You simply need to open the key fob to access the worn-out batteries. After that, you can swap the old batteries for the new ones.

2 Type of Replacing the Mercedes Benz Key Fob Battery

As said earlier, the key fob of your Mercedes is complicated. You can never ignore the signs the fob throws whenever its battery is about to run empty. With the Mercedes models, once the battery is out, there is much you can’t do with the car. You may even find yourself locked out.

However, that shouldn’t bother you because I will continue and give you a detailed guide you ought to follow to perform the replacement like a pro.

Determine Whether the Key Fob is Chrome or Smart

As the Mercedes-Benz vehicles keep advancing, so does their key fob. Therefore, you may have noticed that the newly released models use the chrome fobs as opposed to the smart ones. Both types of fobs look similar.

But, the difference arises when it comes to replacing the batteries in addition to the features. Therefore, you should start by establishing if the fob is smart or chrome because this will determine the procedure you are going to follow, as well as the batteries to use.

When it comes to the latest chrome models, you should spot a red button, triangular in shape. This button is usually the ‘panic button’ and usually has the word panic written in capital letters. If you happen to have this fob, you should buy one CR2025 coin battery for your replacement.

When it comes to the old chrome keys, the panic button is usually circular in shape. For this fob, you will need two CR2025 batteries. The batteries of both the new and the old chrome keys are usually replaced in a similar way.

When it comes to the smart keys, they usually have a plastic casing, black in color. The only difference between the old and the new smart keys is that the new version usually has a red panic button, circular in shape. The old version doesn’t carry this button.

Type1. Chrome Keys

1. Pull the Tab at the Bottom of the Fob

By now, you should be able to distinguish whether your fob is chrome or smart. If you happen to use the chrome key, either a new version or the old one, you should start by pulling on the tab, usually at the bottom of the key. It’s usually small in size square in shape and has a silver ring. Once the tab is pulled, it should release the manual metal key which falls out of its slot.

2. Push the Key Out of the Way

Once the key is out of its slot, it should leave a gap at the bottom of the holder. One end of the gap is usually narrow while the other has a dip. Push the metallic key to the end that is narrow. By doing so, you will be loosening the fob’s cover.

3. Remove the Cover

With the key pushed towards the narrow end, the cover of your fob should reattach from the key holder without any trouble. If it doesn’t, make sure that the key is pushed far enough. Once the cover snaps off, the batteries of your fob should be visible.

4. Remove and Replace the Old Battery(s)

Once the cover is out of your way, you should proceed and remove the old battery(s). Ensure that you note the manner in which the battery is placed to avoid placing the new battery in the wrong direction. Once you are sure, go ahead and swap the battery.

5. Return the Cover and the Key

After the new battery is correctly placed in its holder, you should go ahead and return the cover in its original position. Continue to return the key in its holder in case you don’t want to lose it.

Type2. Smart Keys

1. Pull the Black Clasp

The handle should release the key out of its holder. Hold the key using your other hand as you pull the latch.

2. Push the Metal Key to the Open End

After the clasp is pulled, an empty area will remain beneath the key holder. Push the key into that empty area to help open the cover, revealing the battery compartment.

3. Open the Compartment

Once the key is pushed completely, you should be able to lift the battery compartment out of the holder button, now that the compartment will have to jut out slightly. Continue to pull one end of the compartment out of the key holder.

4. Remove and Replace the Old Batteries

Once the battery compartment is pulled out of the key holder, you should see two batteries. Remove them and replace them with the new CR2025 you just bought.

5. Slide Back the Battery Compartment and the Key into Their Original State

With the newly bought batteries in position, your next step should be to return the battery compartment and the key into their original positions. Slide the battery housing towards the key holder. You should hear a click to tell you that the compartment is in the right position. For the key, go ahead and put it back into the slot, vertically to ensure that it’s secure.

Here is the great YouTube video I found for you below:


Replacing the battery in your Mercedes key fob shouldn’t be a bother. With the guide provided in this article, you should be able to replace the battery regardless of the version of the fob your car uses. Read through the article to understand which procedure you should follow.

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