How to Replace the Battery in a Mercedes-Benz New E Key?
2 Answers
There is a button on the back of the key. Press this button and slide the back cover of the key forward to open it. The battery is located in the slot nearby and can be replaced. During the replacement process, be sure to note the battery model. Most Mercedes-Benz key batteries are of the 3V-CR2025 type. After removing the old battery from the slot, replace it with a new one, then reattach the back cover of the key. More details are as follows: 1. The lifespan of a Mercedes-Benz key battery is generally two years, while the original factory battery can last up to six years. 2. When the key battery is low, the Mercedes-Benz vehicle will provide two types of alerts: one is when you press the ignition switch, the dashboard will display a message prompting you to replace the key battery. 3. The second alert is when you press the lock or unlock button on the key. If the indicator light on the key dims or does not light up, it is time to replace the battery.
I previously replaced the battery for my Mercedes E key myself, and it felt quite simple—anyone can do it. Just find a thin tool, like a small screwdriver or even a coin. Near the bottom of the key's backside, there's a small gap. Gently pry open the casing, but don’t use too much force to avoid damage. Once opened, you’ll see the circuit board with a circular battery compartment in the middle—typically a CR2032 battery. Pay attention to the positive and negative terminals. Carefully remove the old battery, avoiding contact with the metal parts to prevent static discharge. Insert the new battery, ensuring the positive side faces up, then snap the casing back into place. If the key still doesn’t respond, check if the battery is inserted backward or is dead. Generally, the battery lasts about two years, so I recommend checking its charge every six months to avoid remote failure when you’re out. Handling such small tasks yourself saves money and hassle—no need to make a special trip to the shop.
