A Mercedes-Benz key fob is quite the status symbol. It opens some of the most exclusive and luxurious car doors in the world and is quite a statement of your own success and affluence. Unfortunately, the key fob is still subject to the same laws of physics as everything else, and the batteries run out.
As things stand, Mercedes-Benz are yet to invent a special kind of high-end luxury battery that runs 100 times longer than any other pretty typical key fob battery. If you want to replace the Mercedes key fob battery, then you’ll need to know the steps.
Signs That You Need Mercedes Key Fob Battery Replacement
Where some key fobs out there have LCD screens now that tell you when the battery is dying, other more basic ones do not have that luxury. Many Mercedes-Benz key fobs, while beautiful and elegant, are still typically more straightforward and “analog” in their buttons and construction.
If you experience any of the following things, then it’s a sign that it’s time to replace the Mercedes key fob battery.
- Signal strength is weaker, meaning that you are only able to open your car from much closer than usual. Normal range is 50 feet, if it doesn’t work at 40-50 feet at least, then signal strength is weakened.
- You have to press the button multiple times for it to register, send a signal and open/lock the doors.
- It is working quite well in the morning but then in the afternoon not so well, and continues in this inconsistent manner.
How to Replace Mercedes Key Fob Battery
The good news is that changing the battery in your Mercedes-Benz key fob is actually a very simple procedure. It should only take you two minutes and you won’t need any additional components other than what’s in the key fob already.
In order to help more Mercedes-Benz drivers, we’ve prepared two explanations to cover the newer generation of keys and the previous generation of smart keys. The first description below suits Mercedes cars from 2017 to the present. The second description is useful for Mercedes cars from 2016 and earlier with the smart key.
Mercedes Key Fob Battery Replacement (2017-Present Models)
The following simple step-by-step process is all you need to do to replace the battery in these Mercedes-Benz key fobs.
Step 1: Push the small metal button on the back of the key fob and slide the back of the key fob off the casing.
Tip: If you struggle to press the button and slide the back of the casing at the same time, then first press the button to release the valet key. Then, use the valet key in one hand to push the button down while you use your other thumb to slide the fob back away from the rest of the casing.
Step 2: The next thing you have to do is release the battery. It is housed with the inner casing. On the left side of the inner casing, you’ll see a small tab. Use your fingernail or perhaps a small coin or some other flat object to release that tab.
Step 3: Pull on the tab and the battery will come out inside its own case. Pop the battery out of the case and confirm that the replacement battery you have is the right one. It is normally a CR 2032 3-volt battery. It’s a silver-colored disc.
Step 4: Put the new battery in the same place and position in which you found the first one. If you noticed, the side of the battery with the writing (CR 2032…) should be facing down, and the blank side of the battery facing up.
Step 5: Battery now in place, slide the battery back into the key fob slot, making sure to push it all the way back in.
Step 6: Replace the back of the key fob, along with the valet key (if you used it).
Mercedes Key Fob Battery Replacement (2010-2016 Models)
If you have a somewhat older Mercedes-Benz --- still classy of course --- then your key fob will look slightly different to the newer one. You might notice it has more of a polished chrome finish compared to the newer one which is more of a “brushed aluminum” look.
Step 1: Look on the bottom of the key fob and you’ll find a small black button. Push that to release the valet key.
Step 2: Use the ‘bit’ on the end of the valet key to lever off the black backing panel of the key fob. Place the bit of the valet key into the gab between the edge of the black backing panel where it meets the chrome edge by the key slot and then just pop it open.
Step 3: Looking under the backing panel, you’ll see where the battery is. Unlike the newer key fobs, the writing on the battery is facing up. You’ll also notice that the battery designation is different, even though it has the same power rating of 3 volts.
Tip: The older models use the CR 2025 3-volt battery. You can confirm by looking at the writing on the top. It should be a Panasonic battery.
Step 4: Remove the old battery and place the new one inside. Make sure you position it in the same way as the old one.
Step 5: Snap the back panel back into place and restore the valet key by simply sliding it into the key slot.
How Long Does the Mercedes Key Fob Battery Last?
The good news is that you will rarely have to worry about getting a battery and changing it, because those Panasonic batteries last on average between 3 and 4 years. As you can see, the procedure for battery replacement is very simple regardless of whatever model year Mercedes-Benz you are driving.
The 3-volt Panasonic batteries can be purchased both online and at your local Mercedes-Benz dealerships. If you’re struggling with the process in any way, those guys at the dealership will undoubtedly offer their assistance.
What Happens When the Mercedes Key Fob Battery Dies?
When your Mercedes key fob battery is dying or at death’s door, then you will notice a drop in its functionality, for sure. As the battery gets weaker and close to death, you might notice that you have to press on the fob multiple times in order to get it to work. When the battery is dead, then the fob won’t work at all in any of its functions.
I Changed the Mercedes Key Fob Battery but It Still Won’t Work
If you’ve changed the battery for a fresh one but are still experiencing problems with the key fob, then you should contact the dealership and test the key fob for a technical fault. There’s a chance that the key fob has an internal component not working, which is stopping the signal from being sent out properly.