Replacing the key battery
DANGER Serious damage to health caused by swallowing batteries
Batteries contain toxic and corrosive substances. Swallowing batteries may cause serious damage to health.
There is a risk of fatal injury.
Keep batteries out of the reach of children.
If batteries are swallowed, seek medical attention immediately.
ENVIRONMENTAL NOTE Environmental damage due to improper disposal of batteries
Batteries contain pollutants. It is illegal to dispose of them with the household rubbish.
Dispose of batteries of in an environmentally responsible manner. Take discharged batteries to a qualified specialist workshop or to a collection point for used batteries. Requirements:
you require a CR 2025 3 V cell battery
Checking the battery
Press the 
or 
button.
or button. The battery is discharged if indicator lamp 
does not light up briefly.
If the key battery is checked within the reception range of the vehicle, pressing the or button locks or unlocks the vehicle accordingly.
Changing the battery
Mercedes-Benz recommends that you have the battery replaced by a qualified specialist workshop.
Remove the emergency key More.
Press emergency key 
into the opening in the key in the direction of the arrow until battery compartment cover opens. When doing so, do not hold battery compartment cover shut.
into the opening in the key in the direction of the arrow until battery compartment cover opens. When doing so, do not hold battery compartment cover shut. Tap the key against the palm of your hand so that battery 
falls out of the battery compartment.
falls out of the battery compartment. Insert the new battery into the battery tray with the positive pole facing upwards. Use a lint-free cloth to do so.
Fit battery compartment cover to the key casing with the front lugs first and push it closed.
to the key casing with the front lugs first and push it closed. Slide emergency key back into the key More.
back into the key More.