How to Replace the Battery in a Mercedes-Benz S-Class Key?
2 Answers
To replace the battery in a Mercedes-Benz S-Class key, follow these steps: 1. Remove the mechanical key; 2. Insert a tool into the slightly larger hole at the back of the key slot and gently pry it open; 3. Press lightly on the battery to remove and replace it. Taking the 2021 Mercedes-Benz S-Class as an example, its body dimensions are: length 5290mm, width 1921mm, height 1503mm, with a wheelbase of 3216mm and a fuel tank capacity of 76 liters. The 2021 Mercedes-Benz S-Class is equipped with a 3.0T twin-turbocharged engine, delivering a maximum power of 230kW and a maximum torque of 450Nm, paired with a 9-speed automatic transmission.
Last time when I was driving a Mercedes-Benz S-Class, the key suddenly stopped working. I figured out how to replace the battery myself, and it was super convenient. First step is to check the key—usually there's a small groove on the side. Use your fingernail or a small plastic tool to gently pry it open. Then the casing will separate automatically, revealing a small, round coin-cell battery inside, typically a CR2025 or CR2032 model. Before removing the old battery, make sure to note the positive (+) side, which usually faces outward. Insert the new battery in the same orientation—don’t reverse it, or the remote won’t work. Finally, carefully align the casing clips and press them shut. Test the lock/unlock buttons to confirm it’s working. Simple tools like a business card or plastic card from home will do—avoid metal to prevent scratches. The whole process is quick, easy, and saves you a trip to the dealership. The battery costs just a few bucks at the supermarket, and replacing it every two years prevents malfunctions.
