Mercedes-Benz M-Class 2012 Owners Manual - Manual (Page 82)

X To deactivate: press and hold button :
for about five seconds until a tone sounds.
X
To activate: press and hold button ; for
about five seconds until a tone sounds.
i If you press one of the two buttons and
do not hear a tone, the relevant setting has
already been selected.
You can also switch the automatic locking
function on and off using the on-board
computer (
Y
page 235).
Unlocking the driver's door
(mechanical key)
If the vehicle can no longer be unlocked with
the SmartKey, use the mechanical key.
If you use the mechanical key to unlock and
open the driver's door, the anti-theft alarm
system will be triggered (
Y
page 68).
X Take the mechanical key out of the
SmartKey (
Y
page 75).
X
Insert the mechanical key into the lock of
the driver's door as far as it will go.
X Turn the mechanical key counterclockwise
to position 1.
The door is unlocked.
X
Turn the mechanical key back and remove
it.
X Insert the mechanical key into the
SmartKey.
Locking the vehicle (mechanical key)
If the vehicle can no longer be locked with the
SmartKey, use the mechanical key.
X
Open the driver's door.
X
Close the front-passenger door, the rear
doors and the tailgate.
X Press the locking button (
Y
page 79).
X Check whether the locking knobs on the
front-passenger door and the rear doors
are still visible. Press down the locking
knobs by hand, if necessary.
X Close the driver's door.
X Take the mechanical key out of the
SmartKey (
Y
page 75).
X Insert the mechanical key into the lock of
the driver's door as far as it will go.
X Turn the mechanical key clockwise as far
as it will go to position 1.
X Turn the mechanical key back and remove
it.
X Make sure that the doors and the tailgate
are locked.
X Insert the mechanical key into the
SmartKey.
80
Doors
Opening/closing