What is the tutorial for replacing the battery in an old Mercedes-Benz E230 key?

[MelanieMarie]

Here is the method for replacing the battery in an old Mercedes-Benz E230 key: 1. There is a small switch in the upper middle part of the back of the key. Gently press it to remove the mechanical key, then press the key back cover release button to remove the back cover. 2. The battery is located in the battery compartment on the left side of the key. Remove the old battery and insert a new one, ensuring the "+" side faces upward. 3. Reinstall the key cover and mechanical key, then operate the key's lock and unlock buttons to check and confirm that the doors can be locked/unlocked. 4. Note: The replacement battery must be of the same specifications. Only use a new battery with the same rated voltage, size, and specifications to replace the old one.