Page 97 of 502

Problems with the SmartKey
Problem
Possible causes/consequences and
M
MSolutions You can no longer lock
or unlock the vehicle
using the SmartKey. The SmartKey battery is discharged or nearly discharged.
X Check the SmartKey battery (Y page 94) and replace it if nec-
essary (Y page 94).
If this does not work:
X Unlock (Y page 98) or lock (Y page 99) the vehicle using the
mechanical key. There is interference from a powerful source of radio waves.
X Unlock (Y page 98) or lock (Y page 99) the vehicle using the
mechanical key. The SmartKey is faulty.
X Unlock (Y page 98) or lock (Y page 99) the vehicle using the
mechanical key.
X Have the SmartKey checked at a qualified specialist workshop. You can no longer lock
or unlock the vehicle
using KEYLESS-GO. KEYLESS-GO was deactivated.
X Reactivate KEYLESS-GO (Y page 91). The SmartKey battery is discharged or nearly discharged.
X Check the SmartKey battery (Y page 94) and replace it if nec-
essary (Y page 94).
If this does not work:
X Unlock (Y page 98) or lock (Y page 99) the vehicle using the
mechanical key. There is interference from a powerful source of radio waves.
X Unlock (Y page 98) or lock (Y page 99) the vehicle using the
mechanical key. KEYLESS-GO is malfunctioning.
X Lock/unlock the vehicle using the remote control function of
the SmartKey.
X Have the vehicle and SmartKey checked at a qualified specialist
workshop.
If the vehicle can also not be locked/unlocked using the remote
control function:
X Lock (Y page 98) or unlock (Y page 99) the vehicle using the
mechanical key.
X Have the vehicle and SmartKey checked at a qualified specialist
workshop. SmartKey
95Opening and closing Z
Page 98 of 502

Problem
Possible causes/consequences and
M
MSolutions The engine cannot be
started using the
SmartKey. The on-board voltage is too low.
X Switch off non-essential consumers, e.g. seat heating or interior
lighting, and try to start the engine again.
If this does not work:
X Check the starter battery and charge it if necessary
(Y page 430).
or
X Jump-start the vehicle (Y page 432).
or
X Consult a qualified specialist workshop. The engine cannot be
started using the Start/
Stop button. The
SmartKey is in the vehi-
cle. The vehicle is locked.
X Unlock the vehicle and try to start the vehicle again. The SmartKey battery is discharged or nearly discharged.
X Check the SmartKey battery (Y page 94) and replace it if nec-
essary (Y page 94).
If this does not work:
X Start your vehicle with the SmartKey in the ignition lock. There is interference from a powerful source of radio waves.
X Start your vehicle with the SmartKey in the ignition lock. You have lost a Smart-
Key. X
Have the SmartKey deactivated at a qualified specialist work-
shop.
X Report the loss immediately to the vehicle insurers.
X If necessary, have the locks changed as well. You have lost the
mechanical key. X
Report the loss immediately to the vehicle insurers.
X If necessary, have the locks changed as well. 96
SmartKeyOpening and closing
Page 99 of 502

Doors
Important safety notes
G
WARNING
If children are left unsupervised in the vehicle, they could:
R open the doors, thus endangering other
people or road users.
R get out and disrupt traffic.
R operate the vehicle's equipment.
Additionally, children could set the vehicle in
motion if, for example, they:
R release the parking brake.
R shifting the automatic transmission out of
park position P
R Start the engine.
There is a risk of an accident and injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children or animals unattended in the
vehicle. Always keep the SmartKey out of
reach of children.
You should preferably place luggage or loads in the trunk. Observe the loading guidelines
(Y page 372). 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 75). If the vehicle has been locked
with the SmartKey or with KEYLESS-GO,
opening a door from the inside will trigger the
anti-theft alarm system. Switch off the alarm
(Y page 86). X
To unlock and open a front door: pull
door handle ;.
If the door is locked, locking knob :pops
up. The door is unlocked and opens.
X To unlock a rear door: pull door han-
dle ;.
Locking knob :pops up and the door
unlocks.
X To open a rear door: pull door handle;
again.
The door opens. Centrally locking and unlocking the
vehicle from the inside
You can centrally lock and unlock the vehicle from the inside. The buttons are located on
both front doors. X
To unlock: press button :.
X To lock: press button ;.
If the front-passenger door is closed, the
vehicle locks. Doors
97Opening and closing Z
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If the driver's door is open, the door stays
unlocked.
Meanwhile, the fuel filler flap will not be
locked or unlocked.
You cannot unlock the vehicle centrally from
the inside if the vehicle has been locked with the SmartKey or KEYLESS-GO.
The doors can be opened from the inside. You
can only open the rear doors from inside the
vehicle if they are not secured by the child-
proof locks (Y page 75).
If the vehicle has been locked with the Smart-
Key or with KEYLESS-GO, opening a door from the inside will trigger the anti-theft alarm sys-
tem. Switch off the alarm (Y page 86).
i If a locked door is opened from the inside,
the previous unlock status of the vehicle
will be taken into consideration if:
R the vehicle was locked using the locking
button for the central locking, or
R if the vehicle was locked automatically
The vehicle will be fully unlocked if it had
previously been fully unlocked. If only the
driver's door had been previously
unlocked, only the door which has been
opened from the inside is unlocked. Automatic locking feature
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.
The vehicle is locked automatically when the
ignition is switched on and the wheels are
turning.
You could therefore be locked out if:
R the vehicle is being pushed.
R the vehicle is being towed.
R the vehicle is on a roller dynamometer.
i You can switch the automatic locking
function on and off using COMAND (see the
separate operating instructions). Power closing
Power closing pulls the doors and trunk lid
into their locks automatically even if they are only partly closed.
X To power close a door: push the door into
the lock up to the first detent position.
Power closing will pull the door fully closed.
X To power close the trunk lid: lightly push
the trunk lid closed.
The power closing function pulls the trunk
lid closed. Unlocking the driver's door (mechan-
ical key)
If the vehicle can no longer be locked or
unlocked with the SmartKey or KEYLESS-GO,
use the mechanical key.
X Take the mechanical key out of the Smart-
Key (Y page 93). 98
DoorsOpening and closing
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X
Insert the mechanical key as far as it will go
into opening :in the protective cap.
X Pull and hold the door handle.
X Pull the protective cap on the mechanical
key as straight as possible away from the
vehicle until it releases.
X Release the door handle. X
Insert the mechanical key into the lock of
the driver's door as far as it will go.
X Turn the mechanical key counter-clockwise
as far as it will go to position 1.
The locking knob pops up and the door
unlocks.
X Turn the mechanical key back and remove
it.
X Insert the mechanical key into the Smart-
Key (Y page 93).
X Carefully press the protective cap onto the
lock cylinder until it engages and is seated firmly. Do not pull the door handle when
doing so.
If you use the mechanical key to unlock and
open the driver's door, the anti-theft alarm system will be triggered. Switch off the alarm
(Y page 86). Locking the vehicle (mechanical key)
If the vehicle can no longer be locked with the SmartKey or KEYLESS-GO, use the mechani-
cal key.
X Open the driver's door.
X Close the front-passenger door, the rear
doors and the trunk lid.
X Press the locking button (Y page 97).
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 Smart-
Key (Y page 93). X
Insert the mechanical key as far as it will go
into opening :in the protective cap.
X Pull and hold the door handle.
X Pull the protective cap on the mechanical
key as straight as possible away from the
vehicle until it releases.
X Release the door handle. Doors
99Opening and closing Z
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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.
The locking knob drops down and the driv- er's door is locked.
X Turn the mechanical key back and remove
it.
X Make sure that the doors and the trunk lid
are locked.
X Insert the mechanical key into the Smart-
Key (Y page 93).
X Carefully press the protective cap onto the
lock cylinder until it engages and is seated
firmly. Do not pull the door handle when
doing so.
i If you lock the vehicle as described above,
the fuel filler flap is not locked. The anti-
theft alarm system is not armed. Trunk
Important safety notes
G
WARNING
If objects, luggage or loads are not secured or not secured sufficiently, they could slip, tip
over or be flung around and thereby hit vehicle
occupants. There is a risk of injury, particu-
larly in the event of sudden braking or a sud-
den change in direction.
Always store objects so that they cannot be
flung around. Secure objects, luggage or loads against slipping or tipping before the
journey.
! The trunk lid swings upwards when
opened. Therefore, make sure that there is
sufficient clearance above the trunk lid.
i You can limit the opening angle of the
trunk lid in COMAND; see the separate
operating instructions.
i The opening dimensions of the trunk lid
can be found in the "Vehicle data" section
(Y page 495).
Do not leave the SmartKey in the trunk. You
could otherwise lock yourself out.
You should preferably place luggage or loads
in the trunk. Observe the loading guidelines
(Y page 372). Obstacle recognition with trunk lid
reversing feature
On vehicles with trunk lid remote closing fea-
ture, the trunk lid is equipped with automatic obstacle recognition with reversing feature. If a solid object blocks or restricts the trunk lid
when automatically opening or closing, this
procedure is stopped. If the trunk lid is stop-
ped during the closing procedure, it will open
again automatically. The automatic obstacle
recognition with reversing feature is only an
aid. It is not a substitute for your attentive-
ness when opening and closing the trunk lid. G
WARNING
The reversing feature does not react:
R to soft, light and thin objects, e.g. small fin-
gers
R over the last 1/3 in (8 mm) of the closing
movement
This means that the reversing feature cannot
prevent someone being trapped in these sit-
uations. There is a risk of injury.
Make sure that no body parts are in close
proximity during the closing procedure. 100
TrunkOpening and closing
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If somebody becomes trapped:
R press the Fbutton on the SmartKey, or
R pull or press the remote operating switch
on the driver's door or
R press the closing or locking button on the
trunk lid, or
R pull on the trunk lid handle Opening and closing manually
Opening X
Press the Fbutton on the SmartKey.
or X Pull handle :.
The trunk lid opens.
Closing X
Pull the trunk lid down using recess :.
Vehicles with trunk lid remote closing
feature or power closing: X
Lightly push the trunk lid closed.
The power closing function pulls the trunk
lid closed.
X Lock the vehicle if necessary with the &
button on the SmartKey or with KEYLESS-
GO (Y page 91).
i If KEYLESS-GO detects a SmartKey in the
trunk, the trunk lid cannot be locked. It then opens again. Opening/closing automatically from
outside
Important safety notes G
WARNING
Parts of the body could become trapped dur-
ing automatic closing of the trunk lid. More-
over, people, e.g. children, may be standing in the closing area or may enter the closing area
during the closing process. There is a risk of
injury.
Make sure that nobody is in the vicinity of the closing area during the closing process.
Use one of the following options to stop the
closing process:
R press the Fbutton on the SmartKey.
R pull or press the remote operating switch
on the driver's door.
R press the closing or locking button on the
trunk lid.
R pull the trunk lid handle. G
WARNING
Combustion engines emit poisonous exhaust
gases such as carbon monoxide. Exhaust
gases can enter the vehicle interior if the
trunk lid is open when the engine is running,
especially if the vehicle is in motion. There is a risk of poisoning.
Always switch off the engine before opening
the trunk lid. Never drive with the trunk lid
open. Trunk
101Opening and closing Z
Page 104 of 502

!
The trunk lid swings upwards when
opened. Therefore, make sure that there is sufficient clearance above the trunk lid.
i The opening dimensions of the trunk lid
can be found in the "Vehicle data" section
(Y page 495).
Opening You can open the trunk lid automatically
using the SmartKey or the handle in the trunk
lid.
X Press and hold the Fbutton on the
SmartKey until the trunk lid opens.
or
X If the trunk lid is unlocked, pull the trunk lid
handle and let it go again immediately.
Closing You can close the trunk lid automatically
using the SmartKey or the closing button in
the trunk lid. X
Press and release closing button :on the
trunk lid.
or X If the SmartKey is located in the immediate
vicinity of the vehicle: press the Fbut-
ton on the SmartKey.
You can release the button as soon as the
trunk lid starts to close.
X To stop the closing process:
R Press the Fbutton on the SmartKey,
or
R Pull the trunk lid handle, or R
Press closing button :or locking but-
ton ;on the trunk lid, or
R Press the remote operating switch on the
driver's door, or
R In vehicles with HANDS-FREE ACCESS:
kick into the sensor detection range
under the bumper with your foot.
i If the
F button on the SmartKey is
pressed or HANDS-FREE ACCESS is initi-
ated after the closing process is stopped,
the trunk lid opens.
Vehicles with trunk lid remote closing
feature and KEYLESS-GO: when all the
doors are closed, you can simultaneously
close the trunk lid and lock the vehicle. The
key must be located to the rear of the vehicle.
X Press and release locking button ;on the
trunk lid.
If a KEYLESS-GO key is detected outside
the vehicle, the trunk lid closes and the
vehicle locks.
i If KEYLESS-GO detects a SmartKey in the
trunk, the trunk lid opens again after it is
closed.
If KEYLESS-GO detects a second SmartKey outside the vehicle, the trunk lid remains
closed. HANDS-FREE ACCESS
Important safety notes G
WARNING
The vehicle's exhaust system may be very hot. You could burn yourself by touching the
exhaust system if you use HANDS-FREE
ACCESS. There is a risk of injury. Always
ensure that you only make the kicking move-
ment within the detection range of sensors. 102
TrunkOpening and closing