Problem
Possible causes/consequences and
0050
0050Solutions 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 343).
or
X Jump-start the vehicle (Y page 345).
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 82) and replace it if nec-
essary (Y page 82).
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. 84
SmartKeyOpening and closing
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 294). Unlocking and opening doors from
the inside
i When a door is opened, the side window
on that side opens slightly. When the door
is closed, the side window closes again.
! The side windows will not open/close if
the battery is discharged or if the side win- dows have iced up. It will then not be pos-
sible to close the door. Do not attempt to
force the door closed. You could otherwise
damage the door or the side window.
You can open a door from inside the vehicle
even if it has been locked. If the vehicle has
been locked with the SmartKey or with KEY-
LESS-GO, opening a door from the inside will trigger the anti-theft alarm system. Switch off
the alarm (Y page 76). X
Pull door handle 0044.
If the door is locked, locking knob 0043pops
up. The door is unlocked and opens. Centrally locking and unlocking the
vehicle from the inside
You can centrally lock and unlock the vehicle from the inside. The buttons are on both
doors. X
To unlock: press button 0043.
X To lock: press button 0044.
If the front-passenger door is closed, the
vehicle locks.
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. Doors
85Opening and closing Z
The doors can be opened from the inside.
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 76).
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 0043
for about five seconds until a tone sounds.
X To activate: press and hold button 0044for
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 81). X
Insert the mechanical key into opening 0043
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. 86
DoorsOpening and closing
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 0047.
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 81).
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 76). 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 and the
trunk lid.
X Press the locking button (Y page 85).
X Check whether the locking knob on the
front-passenger door is still visible. Press
the locking knob down by hand, if neces-
sary. X
Close the driver's door.
X Take the mechanical key out of the Smart-
Key (Y page 81). X
Insert the mechanical key into opening 0043
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 clockwise as far as
it will go to position 0047.
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. Doors
87Opening and closing Z
X
Insert the mechanical key into the Smart-
Key (Y page 81).
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 397).
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 294). 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.
If somebody becomes trapped:
R press the 0054button 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 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. 88
TrunkOpening and closing
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 0054button 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. 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.
! 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 397).
Opening You can open the trunk lid automatically
using the SmartKey.
X Press and hold the 0054button on the
SmartKey until the trunk lid opens.
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 0043on the
trunk lid.
or X If the SmartKey is located in the immediate
vicinity of the vehicle: press the 0054but-
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 0054button on the SmartKey,
or
R Press closing button 0043or locking but-
ton 0044on 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
0054 button on the SmartKey is
pressed or HANDS-FREE ACCESS is initi-
ated after the closing process is stopped,
the trunk lid opens. Trunk
89Opening and closing Z
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 0044on 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.
! If the SmartKey is within the rear detec-
tion range of KEYLESS-GO, the following
situations, for example, could lead to the
unintentional opening of the trunk:
R using a car wash
R using a power washer
Make sure that the SmartKey is at least
10 ft (3 m) away from the vehicle.
General notes With KEYLESS-GO and HANDS-FREE
ACCESS, you can open or close the trunk lid
or stop the procedure without using your
hands. This is useful if you have your hands
full. To do this, make a kicking movement
under the bumper with your foot. Observe the following points:
R Carry your KEYLESS-GO key about your
person. The KEYLESS-GO key must be in
the rear detection range of the vehicle.
R When making the kicking movement, make
sure that you are standing firmly on the
ground and that there is sufficient clear-
ance to the rear of the vehicle. You could
otherwise lose your balance e.g. on ice. R
Always ensure that you only make the kick-
ing movement within the detection range of
sensors 0043.
R Stand at least 12 in (30 cm) away from the
rear area while doing so.
R Do not come into contact with the bumper
while making the kicking movement. Oth-
erwise, the sensors may not function cor-
rectly.
R HANDS-FREE ACCESS does not function
when the engine is started.
R If a KEYLESS-GO key is within the rear
detection range of KEYLESS-GO, HAND-
FREE ACCESS could be triggered. The trunk
lid could thus be opened or closed unin-
tentionally, for example, if you:
- sit on the edge of the trunk.
- set something down or lift something up
behind the vehicle.
- polish the rear of the vehicle.
Do not carry the KEYLESS-GO key about
your person in these situations or in situa-
tions similar to these. This will prevent the
unintentional opening/closing of the trunk. 90
TrunkOpening and closing
R
Dirt caused by road salt around sensors 0043
may restrict functionality.
R Using the HANDS-FREE ACCESS with a
prosthetic leg may restrict functionality.
Operation X
To open/close: kick into sensor detection
range 0043under the bumper with your foot.
You will hear a warning tone while the trunk lid is opening or closing.
X If the trunk lid does not open after sev-
eral attempts: wait at least ten seconds
then move your leg under the bumper once
again.
i If you hold your foot under the bumper for
too long, the trunk lid does not open or
close. Repeat the leg movement more
quickly if this occurs.
To stop the opening or closing procedure:
R kick with your leg in the sensor detection
range 0043under the bumper or
R press the closing button in the trunk lid or
R press the 0054button on the SmartKey
If the trunk lid closing procedure has been
stopped:
R move your foot under the bumper again and
the trunk lid will open.
If the trunk lid opening procedure has been
stopped:
R move your foot under the bumper again and
the trunk lid will close. Opening/closing automatically from
inside
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 0054button 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. 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.
! 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 397). Trunk
91Opening and closing Z