page 98 MERCEDES-BENZ R-Class 2012 W251 Owner's Guide

Removing the mechanical keyXPush release catch : in the direction of
the arrow and at the same time, remove
mechanical key ; from the SmartKey.
SmartKey battery
Important safety notes
It is advisable to have batteries replaced at a
qualified specialist workshop, e.g. at an
authorized Mercedes-Benz Center.
GWARNING
Batteries contain toxic and caustic
substances. For this reason, keep batteries
out of the reach of children.
If a battery has been swallowed, seek medical
help immediately.
GWARNING
The SmartKey batteries contain perchlorate
material, which may require special handling
and regard for the environment. Observe
government disposal guidelines. California
residents, see www.dtsc.ca.gov/
HazardousWaste/Perchlorate/
index.cfm .
Checking the batteryXPress the & or % button.
The SmartKey battery is working properly if
battery check lamp : lights up briefly.
If battery check lamp : does not light up
briefly during the test, the SmartKey battery
is discharged.
XChanging the battery ( Y page 76)
i
The battery can be obtained from any
authorized Mercedes-Benz Center.
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.
XTake the mechanical key out of the
SmartKey ( Y page 75).XPress mechanical key ; into the opening
in the SmartKey in the direction of the76SmartKeyOpening/closing

Problems with the SmartKeyProblemPossible causes/consequences and M SolutionsYou cannot lock or
unlock the vehicle
using the SmartKey.The SmartKey battery is discharged or nearly discharged.XTry again to lock/unlock the vehicle using the remote control
function of the SmartKey. Point the tip of the SmartKey at the
driver's door handle from close range and press the %/
& button.
If this does not work:
XCheck the SmartKey battery and replace it if necessary
( Y page 76).XLock ( Y page 81) or unlock ( Y page 81) the vehicle using
the mechanical key.The SmartKey is faulty.XLock ( Y page 81) or unlock ( Y page 81) the vehicle using
the mechanical key.XHave the SmartKey checked at a qualified specialist workshop.You can no longer lock
or unlock the vehicle
using KEYLESS-GO.KEYLESS-GO is in standby mode because the vehicle has not been
unlocked for an extended period.XPull the door handle twice and then insert the SmartKey into the
ignition lock.There is interference from a powerful source of radio waves.XLock/unlock the vehicle using the remote control function of
the SmartKey. Point the tip of the SmartKey at the driver's door
handle from close range and press the %/& button.There is a malfunction with KEYLESS-GO.XLock/unlock the vehicle using the remote control function of
the SmartKey. Point the tip of the SmartKey at the driver's door
handle from close range and press the %/& button.XHave KEYLESS-GO checked at a qualified specialist workshop.
If this does not work:
XCheck the SmartKey battery and replace it if necessary
( Y page 76).XLock ( Y page 81) or unlock ( Y page 81) the vehicle using
the mechanical key.You have lost a
SmartKey.XHave the SmartKey canceled at an authorized Mercedes-Benz
Center.XReport the loss immediately to the vehicle insurers.XIf necessary, have the locks changed as well.78SmartKeyOpening/closing

ProblemPossible causes/consequences and M SolutionsYou have lost the
mechanical key.XReport the loss immediately to the vehicle insurers.XIf necessary, have the locks changed as well.The engine cannot be
started using the
SmartKey.The on-board voltage is too low.XSwitch off non-essential consumers, e.g. seat heating or interior
lighting, and try to start the engine again.
If this does not work:
XCheck the starter battery and charge it if necessary
( Y page 310).
or
XJump-start the vehicle ( Y page 313).
or
XConsult a qualified specialist workshop.The engine cannot be
started using KEYLESS-
GO. The SmartKey is in
the vehicle.A door is open. Therefore, the SmartKey cannot be detected as
easily.XClose the door and try to start the vehicle again.There is interference from a powerful source of radio waves.XStart your vehicle with the SmartKey in the ignition lock.Doors
Important safety notes
GWARNING
When leaving the vehicle, always remove the
SmartKey from the ignition lock. Always take
the SmartKey with you and lock the vehicle.
Do not leave children unsupervised in the
vehicle, even if they are secured in a child
restraint system, and do not give them access
to an unlocked vehicle. A child's unsupervised
access to a vehicle could result in an accident
and/or serious personal injury. They could:
R injure themselves on vehicle parts
R be seriously or fatally injured by extreme
heat or cold
R injure themselves or have an accident with
vehicle equipment that may still be in
operation even after the SmartKey has
been removed from the ignition, such as the
seat adjustment, steering wheel
adjustment or memory function.
If children open a door, they could cause
severe or even fatal injury to other persons; if
they get out of the vehicle, they could injure
themselves when doing so or be seriously or
even fatally injured by any passing traffic.
Do not expose the child restraint system to
direct sunlight. The child restraint system's
metal parts, for example, could become very
hot, and a child could be burned on these
parts.GWARNING
Do not carry heavy or hard objects in the
passenger compartment or cargo
compartment unless they are firmly secured
in place.
Doors79Opening/closingZ

Unsecured or improperly positioned cargo
increases a child's risk of injury in the event
of
R strong braking maneuvers
R sudden changes of direction
R an accident
Unlocking and opening doors from
the inside
You can open a door from inside the vehicle
even if it has been locked. You can only open
the rear doors from inside the vehicle if they
are not secured by the child-proof locks
( Y page 63).
Only open the door when the traffic situation
permits.
If the vehicle was previously locked with the
SmartKey or with KEYLESS-GO, opening the
vehicle from the inside will activate the anti-
theft alarm system. Switch off the alarm
( Y page 69).
XPull door handle ;.
If the door is locked, locking knob : pops
up. The door is unlocked and can be
opened.
Centrally locking and unlocking the
vehicle from the inside
You can centrally lock or unlock the vehicle
from the inside.
The central locking/unlocking button does
not lock or unlock the fuel filler flap.
The buttons are located on both front doors.
i You cannot unlock the vehicle centrally
from the inside if the vehicle has been
locked with the SmartKey or KEYLESS-GO.
i It is only possible to lock the vehicle
centrally if the front-passenger door is
closed.XTo unlock: press button :.XTo lock: press button ;.
If all the doors and the tailgate are closed,
the vehicle locks.
You can open a front door from inside the
vehicle even if it has been locked. Only open
the door when the traffic situation permits.
If the vehicle has been locked with the central
locking button:
R and the SmartKey is set to its factory
setting, the entire vehicle is unlocked if a
front door is opened from the inside
R and the SmartKey is set to an individual
setting, only the front door that is opened
from inside the vehicle is unlocked.
If the vehicle has been locked centrally with
the SmartKey or with KEYLESS-GO, it is not
unlocked when the release button for the
central locking is used.
Automatic locking feature
The vehicle locks automatically when the
ignition is switched on and the wheels of the
80DoorsOpening/closing

vehicle are turning at a speed of more than
9 mph (15 km/h).
You could therefore be locked out when:
R the vehicle is being pushed.
R the vehicle is being towed.
R the vehicle is being tested on a
dynamometer.
You can switch the automatic locking
function on and off using the on-board
computer ( Y page 208).
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 69).
XTake the mechanical key out of the
SmartKey ( Y page 75).XInsert the mechanical key into the lock of
the driver's door as far as it will go.XTurn the mechanical key counter-clockwise
as far as it will go to position 1 and hold
it in this position.XPull the door handle beyond the first
resistance.
The locking knob pops up.
The door is unlocked.XTurn the mechanical key back and remove
it.XPull the door handle again.XInsert the mechanical key into the
SmartKey.
Locking the vehicle
If the vehicle can no longer be locked with the
SmartKey, you can lock it by taking the
following steps.
XClose the front-passenger door, the rear
door on the front-passenger side and the
tailgate.XOpen the driver’s door and the rear door on
the driver’s side.XPress the locking button on the driver’s
door ( Y page 80).
The locking knobs in the front-passenger
door and in the rear doors drop down.XPress down the locking knobs in the front-
passenger and rear doors manually, if
necessary.XClose the driver's door from the outside.XPress down the locking knob of the driver's
door by reaching in through the open rear
door.
i Make sure that you have the SmartKey on
your person and that it has not been left in
the vehicle.
XClose the rear door on the driver’s side.XMake sure that the doors and the tailgate
are locked.
i If you lock the vehicle as described above,
the fuel filler flap is not locked. The anti-
theft alarm system is not armed.
Cargo compartment
Important safety notes
Do not leave the SmartKey in the cargo
compartment. You could otherwise lock
yourself out.
Cargo compartment81Opening/closingZ

compartment opening when closing the
tailgate. Be especially careful when small
children are around.XPull the tailgate down using recess :.XPush the tailgate closed from outside the
vehicle.XIf necessary, lock the vehicle with
the & button on the SmartKey
( Y page 72) or with KEYLESS-GO
( Y page 73).
i
If a KEYLESS-GO key is detected in the
cargo compartment, the tailgate will not
lock.
Opening/closing automatically from
outside
Important safety notes
GWARNING
Make sure the tailgate is closed when the
engine is running and while driving. Among
other dangers, deadly carbon monoxide (CO)
gases may enter vehicle interior resulting in
unconsciousness and death.
! The tailgate swings upwards and to the
rear when opened. Therefore, make sure
that there is sufficient clearance above and
behind the tailgate.
To open the tailgate completely, a minimum
clearance of 7.20 ft (2.20 m) above the
ground is necessary.
Opening
You can open the tailgate automatically using
the SmartKey or the handle in the tailgate.
XPress and hold the F button on the
SmartKey until the tailgate opens.
or
XWhen the tailgate is unlocked, pull the
handle and let it go again immediately.
Closing
GWARNING
Monitor the closing procedure carefully to
make sure no one is in danger of being
injured. To prevent possible personal injury,
always keep hands and fingers away from the
cargo compartment opening when closing the
tailgate. Be especially careful when small
children are around. To stop the closing
procedure, do one of the following:
R Press or pull the remote tailgate opening/
closing switch on the driver's door.
R Press the tailgate closing switch.
R Press the KEYLESS-GO locking/closing
switch.
R Pull outside handle on the tailgate.
R When no SmartKey is inserted in the starter
switch (vehicles with KEYLESS-GO: Make
sure the vehicle's on-board electronics
have status 0): Press button F on the
SmartKey.
You can close the tailgate automatically using
the SmartKey, the closing button 5
or the
locking button 6
.
5 For vehicles with the EASY-PACK tailgate only.
6 For vehicles with the EASY-PACK tailgate and KEYLESS-GO only.Cargo compartment83Opening/closingZ

XTo open: pull remote operating switch :
for the tailgate until the tailgate opens.XTo close: turn the SmartKey to position 1
or 2 in the ignition lock.XPress remote operating switch for
tailgate : until the tailgate is closed.
If the tailgate comes into contact with an
object, the closing procedure is interrupted
and the tailgate reopens.
XTo interrupt the closing procedure: push
or pull remote operating switch for the
tailgate :.
Opening the tailgate from inside the
vehicle
GWARNING
Do not leave children unattended in the
vehicle. Children could open the tailgate from
the inside, which could result in an accident
and/or serious personal injury.
! Always make sure there is sufficient
space when opening.
You can unlock and open the tailgate from
inside the vehicle.
The handle is on the lower part of the tailgate
window on the right-hand side when viewed
in the direction of travel.
XPress handle : in the direction of
arrow ; as far as it will go and hold it there.XFrom this position, pull handle : in the
direction of arrow = as far as it will go and
hold it there.XSwing the tailgate upwards.
i Vehicles with the EASY-PACK tailgate:
If you do not open the tailgate after
unlocking, it will lock again automatically
after a few seconds.
Limiting the opening angle of the
tailgate
Important safety notes
You can limit the opening angle of the tailgate
in the top half of its opening range. This could
be useful, for example, if there is insufficient
space above the tailgate.
! Make sure there is sufficient clearance to
open the tailgate fully when setting the
opening angle. The tailgate could otherwise
be damaged. Ideally, set the opening angle
outside.
Activating
XTo open the tailgate: pull the handle on
the tailgate.XTo stop the opening procedure at the
desired position: press the closing button
( Y page 83) in the tailgate or pull the handle
on the outside of the tailgate again.XTo store the position: press and hold the
closing button in the tailgate until you hear
a short tone.
The opening angle limiter is activated. The
tailgate will now stop in the stored position
when opening.Cargo compartment85Opening/closingZ

DeactivatingXPress and hold the closing button
( Y page 83) in the tailgate until you hear
two short tones.
Side windows
Important safety notes
GWARNING
When opening or closing the windows, make
sure there is no danger of anyone being
harmed by the opening/closing procedure.
The door windows are equipped with the
express operation and automatic reversal
function. If in express operation mode a door
window encounters an obstruction that
blocks its path, the automatic reversal
function will stop the door window and open
it slightly.
The door windows operate differently when
the switch is pulled and held. See the "Closing
when a door window is blocked" section in
this chapter for details.
The closing of a door window can be
immediately halted by releasing the switch or,
if the switch was pulled past the resistance
point and released, by either pressing or
pulling the respective switch.
The closing of the hinged quarter windows can
be immediately halted by pressing or pulling
the switch.
If a window encounters an obstruction that
blocks its path in a circumstance where you
are closing the windows by pressing and
holding button & on the SmartKey or by
pressing and holding the lock button (vehicles
with KEYLESS-GO) on an outside door handle,
the automatic reversal function will not
operate.
Activate the override switch when children
are riding in the back seats of the vehicle. The
children may otherwise injure themselves,
e.g. by becoming trapped in the window
opening.
GWARNING
Do not keep any part of your body up against
the window pane when opening a window. The
downward motion of the pane may pull that
part of your body down between the window
pane and the door frame and trap it there. If
there is a risk of entrapment, release the
switch and pull it to close the window.
Opening and closing the side
windows
:Front left;Front right=Rear right?Rear left
The switches for all side windows are located
on the driver's door. There is also a switch on
each door for the corresponding side window.
The switches on the driver's door take
precedence.
i The side windows cannot be operated
from the rear when the override feature for
the side windows is activated ( Y page 63).
XTurn the SmartKey to position 1 or 2 in the
ignition lock.XTo open: press the corresponding switch.XTo close: pull the corresponding switch.
i
If you press the switch beyond the point
of resistance, an automatic opening/
closing process is started in the
corresponding direction. You can stop
86Side windowsOpening/closing

Resetting the side windows
You must reset each side window if:
R the battery has been disconnected or has
become discharged.
R the side window opens again slightly after
being closed fully.
R the side window can no longer be fully
opened or closed.XClose all the doors.XTurn the SmartKey to position 1 or 2 in the
ignition lock.XPull the corresponding switch on the door
control panel until the side window is
completely closed. ( Y page 86)XHold the switch for an additional second.
If the side window opens again slightly:
XImmediately pull the corresponding switch
on the door control panel until the side
window is completely closed ( Y page 86).XHold the switch for an additional second.XIf the corresponding side window remains
closed after the button has been released,
the side window has been reset correctly.
If this is not the case, repeat the steps
above again.
Problems with the side windows
Problem: a side window cannot be closed
because it is blocked by objects, e.g.
leaves in the window guide.
XRemove the objects.XClose the side window.
Problem: a side window cannot be closed
and you cannot see the cause.
GWARNING
Closing the side windows with increased force
or without the anti-entrapment feature could
lead to serious or even fatal injury. Make sure
that nobody can become trapped when
closing the side windows.
If a side window is obstructed during closing
and reopens again slightly:XImmediately after the window blocks, pull
the corresponding switch again until the
side window has closed.
The side window is closed with increased
force.
If a side window is obstructed again during
closing and reopens again slightly:
XImmediately after the window blocks, pull
the corresponding switch again until the
side window has closed.
The side window is closed without the anti-
entrapment feature.GWARNING
Pulling and holding the switch to close the
door window immediately after it had been
blocked two times will cause the door window
to close without the anti-entrapment feature
for as long as you hold the switch.
Sliding sunroof
Important safety notes
Your vehicle may be equipped with a sliding
sunroof or a panorama roof with power tilt/
sliding panel. In the following section, the
term "sliding sunroof" refers to both types of
sliding sunroof.
GWARNING
When opening or closing the sliding sunroof,
make sure that there is no danger of anyone
being harmed by the opening/closing
procedure.
The sliding sunroof is equipped with
automatic operation and the anti-entrapment
feature. If the movement of the sliding sunroof
is blocked during the closing procedure, the
sliding sunroof will stop and open slightly.
The sliding sunroof operates differently when
the sliding sunroof switch is pressed and held.
See the "Problems with the sliding sunroof"
section for more details.
Sliding sunroof89Opening/closingZ

The opening/closing procedure of the sliding
sunroof can be immediately halted by
releasing the sliding sunroof switch or, if the
sliding sunroof switch was moved past the
resistance point and released, by moving the
sliding sunroof switch in any direction.GWARNING
The sliding sunroof is made out of glass. In the
event of an accident, the glass may shatter.
This may result in an opening in the roof.
In a vehicle rollover, occupants not wearing
their seat belts or not wearing them properly
may be thrown out of the opening. Such an
opening also presents a potential for injury for
occupants wearing their seat belts properly,
as entire body parts or portions of them may
protrude from the passenger compartment.
! Only open the sliding sunroof if it is free
of snow and ice. Otherwise, malfunctions
may occur.
Do not allow anything to protrude from the
sliding sunroof. Otherwise, the seals could
be damaged.
! The weather can change abruptly. It could
start to rain or snow. Make sure that the
sliding sunroof is closed when you leave the
vehicle. The vehicle electronics can be
damaged if water enters the vehicle
interior.
i Resonance noises can occur in addition
to the usual airflow noises when the sliding
sunroof is open. They are caused by minor
pressure fluctuations in the vehicle interior.
Change the position of the sliding sunroof
or open a side window slightly to reduce or
eliminate these noises.
Operating the sliding sunroof
Opening and closing
i You can continue to operate the sliding
sunroof after switching off the engine or
removing the SmartKey from the ignition
lock. This function is available for up to five
minutes or until the driver's or front-
passenger door is opened.
Overhead control panel
:To raise;To open=To close/lowerXTurn the SmartKey to position 1 or 2 in the
ignition lock.XPress or pull the 2 switch in the
corresponding direction.
i If you press the 2 switch beyond the
point of resistance, an automatic opening/
closing process is started in the
corresponding direction. You can stop
automatic operation by operating the
switch again.
The sun protection cover automatically opens
along with the sliding sunroof. You can open
or close the sun protection cover manually
when the sliding sunroof is raised or closed.
Resetting
Reset the sliding sunroof if it does not move
smoothly, or if the battery has been
disconnected or has become discharged.
XRemove the SmartKey from the ignition
lock or select position 0 (KEYLESS-GO).XRemove the fuse for the sliding sunroof
from the fuse box. To find out where the
fuse is located, refer to the fuse allocation
chart in the vehicle tool kit ( Y page 296).XReinsert the fuse.90Sliding sunroofOpening/closing