What is the method for replacing the key battery in the Mercedes-Benz C240 4MATIC?
2 Answers
Mercedes-Benz C240 4MATIC key battery replacement method is: Push the marked switch upward from the tail of the key to remove the mechanical key; Press the marked position on the mechanical key to open the key casing; Use a card to pry the battery from the gaps on both sides and remove it; After replacing the battery, reinstall the casing and put the mechanical key back in place. Taking the 2020 Sport version Mercedes-Benz C240 as an example, its body dimensions are: 4704mm in length, 1810mm in width, 1454mm in height, with a wheelbase of 2840mm, a fuel tank capacity of 66 liters, and a curb weight of 1620kg.
I remember when my Mercedes key needed a battery change, I first checked the key fob for small notches or buttons. Usually, I use a small tool, like a fingernail or a thin screwdriver, to gently pry open the casing—being careful not to apply too much force to avoid damaging the plastic. Remove the old battery, paying attention to the positive and negative markings; the battery type is typically CR2032, which can be easily found at supermarkets. Insert the new battery, ensuring it's placed with the correct polarity. Then, snap the casing back together, making sure the clips are securely in place. Test the remote lock/unlock function; if it doesn't work, you might need to re-pair the key. It's recommended to check the battery life every two years to maintain stable signal performance—safety first. Taking photos to document the original positions before starting is also a smart approach.
