How to Replace Your Mercedes-Benz Key Fob Battery

August 17th, 2022 by

The Mercedes-Benz Key Fob Battery: Everything You Need to Know

The Mercedes-Benz key fob packs an incredible amount of versatility into one sleek little device. You can open and close the windows and sunroof remotely, unlock all the doors or the driver’s only, and with the brand’s KEYLESS GO® technology, unlock the door and start the car without even touching the fob.

What happens when the battery dies? You can still get into the vehicle and drive, but you need a working battery in the key fob to enable proper functionality.

At Ray Catena, we’re always available to help drivers get the most out of their vehicles and are happy to replace your key fob battery. We’ve also put together this guide to understanding how your key fob works and what happens when the battery dies so you know what to expect.

How Do Mercedes-Benz Key Fob Controls Work?

The Mercedes-Benz key fob controls work as long as your device is within a few feet of the vehicle. The key fob acts as a remote control device, which, when activated, can lock and unlock the doors, open the windows and trunk, and more.

When you’re within range of your Mercedes, a short-range radio transmitter in the key fob transmits radio waves, which are picked up by a receiver unit inside the car. Then, when you click on the buttons to trigger an action, the radio waves communicate with the vehicle, activating the systems you want.

What Kind of Battery Does a Mercedes-Benz Key Fob Take?

To power your key fob, you need a working battery. For a Mercedes-Benz key fob, you’ll need a CR 2025 3-volt lithium battery. If you have a Smart Key fob, you’ll require two batteries. The Chrome Key only uses one.

You can find key fob batteries for your Mercedes at your local grocery store or hardware store. Or, stop by one of our Mercedes-Benz dealerships in New Jersey, and we’ll replace the batteries for you.

How Long Does a Mercedes-Benz Key Fob Battery Last?

The battery in your key fob should last for three to four years. However, there are ways to preserve the life of your battery.

  • Keep your key fob out of the cold. If you leave the fob outside or in the garage in the winter, the cold air can drain the charge.
  • Don’t leave your key fob within range of your vehicle when not in use. Because the radio transmitter in the fob will start communicating with the receiver when it’s within range, leaving it near your vehicle could wear out the battery prematurely.

What If I Need to Replace My Mercedes-Benz Key Fob Battery?

If your key fob battery dies, you can still unlock and start your Mercedes-Benz with the mechanical key that’s attached to the fob.

You should use your physical key as a temporary solution until you’re able to replace the battery in your fob. Here’s why: when you don’t lock your Mercedes-Benz with the key fob, the alarm system isn’t activated and the fuel filler cap won’t lock.

Essentially, to enable your vehicle’s electrical systems to function properly, you need to have a working battery.

If your Mercedes-Benz key fob isn’t working properly or it’s time to replace the battery, our expert staff can help. Contact Ray Catena’s service department today or come to our dealership in person – we’re happy to assist.