Mercedes-Benz M-Class 2012 Owners Manual - Manual (Page 78)

Checking the battery
X Press the & or % button.
The battery is working properly if battery
check lamp : lights up briefly
If battery check lamp : does not light up
briefly during the test, the battery is
discharged.
X Changing the battery (
Y
page 76)
i You can obtain the battery at a qualified
specialist workshop.
i If the SmartKey battery is checked within
the signal reception range of the vehicle,
pressing the & or % button locks or
unlocks the vehicle.
Changing the battery
You require a CR 2025 3 V cell battery.
X Take the mechanical key out of the
SmartKey (
Y
page 75).
X Press mechanical key ; into the opening
in the SmartKey in the direction of the
arrow until battery tray cover : opens.
When doing so, do not hold cover : shut.
X Remove battery tray cover :.
X Repeatedly tap the SmartKey against your
palm until battery = falls out.
X Insert the new battery with the positive
terminal facing upwards. Use a lint-free
cloth to do so.
X Make sure that the surface of the battery is
free from lint, grease and all other forms of
contamination.
X Insert the front tabs of battery tray
cover : and then press to close it.
X Insert the mechanical key into the
SmartKey.
X
Check the function of all SmartKey buttons
on the vehicle.
76
SmartKey
Opening/c
losing