
2. this device must accep
tany interference
received, including interference tha tmay
cause undesired operatio nofthe device.
Removal, tampering, or altering of the
device will void any warranties, and is not
permitted. Do not tamper with, alter, or use
the device in any non-approved way.
Any unauthorized modification to this
device could void the user's authority to
operate the equipment. Theft deterrent locking system
Immobilizer
The immobilizer prevents your vehicle from
being started without the correct SmartKey.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. The
engine can be started by anyone with a valid
SmartKey that is left inside the vehicle.
X To activate with the SmartKey: remove
the SmartKey from the ignition lock.
X To activate with KEYLESS-GO: switch the
ignition off and open the driver's door.
X To deactivate: switch on the ignition.
i The immobilizer is always deactivated
when you start the engine. ATA (anti-theft alarm system)
Av isual and audible alarm is triggered if the
alarm system is armed and you open:
R a door
R the vehicle with the mechanical key
R the trunk lid
R the hood
The alarm is not switched off, even if you
close the open door that has triggered it, for
example. i
If the alarm stays on for more than
30 seconds, the mbrace (USA only) or TELE
AI D( Canada only) emergency call system
initiates a call to the Custome rAssistance
Center automatically. The emergency call
system initiates the call provided that:
R you have subscribed to the mbrace/
TELE AID service.
R the mbrace/TELE AID service has been
activated properly.
R the required mobile phone, power supply
and GPS are available. X
To arm: lock the vehicle with the SmartKey
or KEYLESS-GO.
Indicator lamp 0002flashes. The alarm
system is armed after approximately
30 seconds.
X To disarm: unlock the vehicle with the
SmartKey or KEYLESS-GO.
X To stop the alarm using the SmartKey:
insert the SmartKey into the ignition lock.
The alarm is switched off.
or
X Press the 000Bor0009 button on the
SmartKey.
The alarm is switched off. Theft deterrent locking system
79Safety Z 

Useful information
i This Operator's Manual describes all
models and all standard and optional
equipment of your vehicle available at the
time of publication of the Operator's
Manual. Country-specific differences are
possible. Please note that your vehicle may
not be equipped with all features
described. This also applies to safety-
related systems and functions.
i Please read the information on qualified
specialist workshops (Y page 31).SmartKey
Important safety notes
G
WARNING
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. Achild'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.
G
WARNING
If a key ring is too heavy or too large, the
weight acting on the key could cause it to turn
in the ignition lock or catch on the steering
wheel. This could cause the engine to be
switched off suddenly. You may lose control
of the vehicle and cause an accident. Do not
attach any heavy or large key rings to the key
that is inserted in the ignition. General notes
If you cannot lock or unlock the vehicle with
the SmartKey, either the battery in the
SmartKey is discharged, the SmartKey is
faulty or the starter battery is discharged.
X Check the battery in the SmartKey and
replace it if necessary (Y page 85).
X Unlock the driver's door using the
mechanical key (Y page 90).
X Lock the vehicle (Y page 91).
X Have the starter battery and the battery
contacts checked at a qualified specialist
workshop.
If the SmartKey is faulty, contact Roadside
Assistance or a qualified specialist workshop. SmartKey functions
The SmartKey centrally locks/unlocks:
R the doors
R the trunk lid
R the fuel filler flap 82
SmartKeyOpening/closing 

0002
0009 Locks the vehicle
0003 0004 Unlocks the trunk lid
0026 000B Unlocks the vehicle
When unlocking, the turn signals flash once.
When locking, they flash three times.
When it is dark, the surround lighting also
comes on if it is activated in COMAND
(Y page 268).
If you activate the acoustic locking
confirmation function you will hear the
following, depending on the date of
production of the vehicle:
R an acoustic signal when locking
or
R one acoustic signal when unlocking and
three when locking.
The audible signal can be activated and
deactivated using the on-board computer
(Y page 388).
X To unlockc entrally:press the000B
button.
If you do not open th evehicle within
approximately 40 seconds of unlocking:
R the vehicle is locked again.
R the thef tdeterrent locking system is armed
again.
X To lock centrally: press the0009button. KEYLESS-GO
Important notes on the use of KEYLESS-
GO R
Do not keep the KEYLESS-GO key together
with:
- electronic devices, e.g. a mobile phone
or another key
- metallic objects, e.g. coins or metal foil.
This can affect the functionality of
KEYLESS-GO.
R Bear in mind that the engine can be started
by any of the vehicle occupants if there is
a KEYLESS-GO key in the vehicle.
Locking and unlocking centrally You can start, lock or unlock the vehicle using
KEYLESS-GO. To do this, you only need carry
the SmartKey with you. You can combine the
KEYLESS-GO functions with those of a
conventional key, e.g. using KEYLESS-GO to
unlock and pressing the
0009button to lock.
When locking and unlocking using KEYLESS-
GO, the distance between the SmartKey and
the corresponding door handle must not
exceed 3 ft (1 m).
KEYLESS-GO checks whether a valid key is in
the vehicle by periodically establishing a radio
connection between the vehicle and the key.
This happens:
R when the external door handles are
touched
R when starting the engine
R while the vehicle is in motion SmartKey
83Opening/closing Z 

Problem Possible causes/consequences and
0004 Solutions
You have lost the
mechanical key. X
Report the loss immediately to the vehicle insurers.
X If necessary, have the locks changed as well. The engine cannot be
started using the
SmartKey. The on-board voltage is too low.
X
Remove the SmartKey and reinsert it into the ignition lock.
X Start the engine within 30 seconds of inserting the SmartKey
into the ignition lock.
X Repeatifn ecessary.
If the engine does not start after several attempts:
X Check the starter battery and charge it if necessary
(Y page 484).
or
X Jump-start the vehicle (Y page 488).
or
X Consult a qualified specialist workshop. The engine cannot be
started using KEYLESS-
GO. The SmartKey is in
the vehicle. Ad
oor is open. Therefore, the SmartKey cannot be detected as
easily.
X Close the door and try to start the vehicle again. There is interference from a powerful source of radio waves.
X
Start your vehicle with the SmartKey in the ignition lock. Doors
Important safety notes
G
WARNING
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. Achild'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. 88
DoorsOpening/closing 

of more than 9 mph (15 km/h), the vehicle
locks automatically.
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 off the automatic locking
function via COMAND (Y page 269).Power closing feature
The power closing feature pulls the doors and
trunk lid into their locks automatically even if
they are only partly closed. G
WARNING
To prevent possible personal injury, always
keep hands and fingers away from the door or
trunk opening when closing a door or the
trunk lid. Be especially careful when small
children are around.
If danger threatens, pull the inside or outside
door handle, or pull the trunk lid handle.
To prevent personal injury, never activate the
closing assist mechanism by tampering with
the door or trunk lid latch. G
WARNING
Only drive with the doors closed. Otherwise,
one or more of the doors could open while the
vehicle is in motion, putting you and/or
others at risk. G
WARNING
Make sure the trunk lid is closed when the
engine is running and while driving. Among
other dangers, deadly carbon monoxide (CO)
gases may enter the vehicle interior resulting
in unconsciousness and death. X
Power closing feature (doors): push the
door past the first detent position of the
lock.
The power closing feature will pull the door
fully closed.
X Power closing feature (trunk lid): lightly
push the trunk lid closed.
The power closing feature will pull the trunk
lid fully closed. 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 79).
X Take the mechanical key out of the
SmartKey (Y page 84).
X Insert the mechanical key into the lock of
the driver's door as far as it will go. X
Firmly turn the mechanical key
counterclockwise as far as it will go to
position 0005and hold it in this position.
X Pull the door handle quickly.
The locking knob pops up.
The door is unlocked.
X Turn the mechanical key back and remove
it.
X Pull the door handle again.
X Insert the mechanical key into the
SmartKey. 90
DoorsOpening/closing 

Locking the vehicle
If the vehicle can no longer be locked with the
SmartKey, you can lock it by taking the
following steps. If the central locking in the
vehicle is malfunctioning, you canno tlock the
trunk.
X Press down the locking knobs on the open
rear doors.
X Close the rear doors.
X Open the front-passenger door.
X Close the driver's door and the trunk lid.
X Press down the locking knob of the driver's
door inside the vehicle.
X Press down the locking knob of the open
front-passenger door.
i Make sure that you have the SmartKey on
your person and that it has not been left in
the vehicle.
X Close the front-passenger door.
X Make sure that the doors and the trunk 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. Trunk
Important safety notes
Do not leave the SmartKey in the trunk. You
could otherwise lock yourself out. G
WARNING
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. Achild'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. G
WARNING
Do not carry heavy or hard objects in the
passenger compartmentort runk unless they
are firmly secured in place.
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 G
WARNING
Make sure the trunk lid is closed when the
engine is running and while driving. Among
other dangers, deadly carbon monoxide (CO) Trunk
91Opening/closing
Z 

Opening/closing automatically from
outside
Important safety notes G
WARNING
Make sure the trun klid is closed when the
engine is running and while driving. Among
other dangers, deadly carbo nmonoxide (CO)
gases may enter the vehicle interior resulting
in unconsciousness and death.
! The trunk lid swings upwards when
opened. Therefore, make sure that there is
sufficient clearance above the trunk lid.
To open the trunk lid completely, a minimum
clearance of 5.90 ft (1.80 m) above the
ground is necessary.
Opening You can open the trunk lid using the
SmartKey.
X
Press and hold the 0004button on the
SmartKey until the trunk lid opens.
Closing G
WARNING
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
trunk opening when closing the trunk lid. Be
especially careful when small children are
around. To stop the closing procedure, do one
of the following:
R Press button 0004on the SmartKey.
R Press the remote trunk opening/closing
switch (on the driver's door).
R Press the trunk closing switch.
R Press the KEYLESS-GO locking/closing
switch.
R Pull the trunk lid handle. Even with the SmartKey removed from the
starter switch or the SmartKey with KEYLESS-
GO removed from the vehicle, the remote
trunk opening/closing switch can be
operated. Therefore, do not leave children
unattended in the vehicle, or with access to
an unlocked vehicle.
Achild's unsupervised
access to a vehicle could result in an accident
and/or serious personal injury.
You can close the trunk lid automatically by
using the closing button 3
or locking button 4
. X
To close: press closing button 0002in the
trunk lid.
X To close and lock simultaneously:
Press locking button 0003in the trunk lid.
i If you leave a KEYLESS-GO key in the
trunk, the trunk lid will not lock. Opening/closing automatically from
inside
G
WARNING
Maintain sight of the area around the rear of
the vehicle while operating the trunk lid with
the door mounted switch. Monitor the closing
procedure carefully to make sure no one is in
danger of being injured.
To interrupt the closing procedure, release
the door mounted remote trunk opening/
closing switch again.
3 For vehicles with the trunk lid remote closing feature only.
4 For vehicles with the trunk lid remote closing feature and KEYLESS-GO only. Trunk
93Opening/closing
Z 

Even with the SmartKey removed from the
starter switch or the SmartKe
ywith KEYLESS-
GO removed from the vehicle, the remote
trunk opening/closing switch can be
operated. Therefore, do not leave children
unattended in the vehicle, or with access to
an unlocked vehicle. Achild's unsupervised
access to a vehicle could result in an accident
and/or serious personal injury. G
WARNING
Make sure the trunk lid is closed when the
engine is running and while driving. Among
other dangers, deadly carbon monoxide (CO)
gases may enter the vehicle interior resulting
in unconsciousness and death.
You can open and close the trunk lid from the
driver's seat when the vehicle is stationary
and unlocked. X
To open: press remote operating switch for
trunk lid 0002until the trunk lid opens.
X To close: press remote operating switch
for trunk lid 0002until the trunk lid is closed. Locking the trunk separately
You can lock the trunk separately.Ify ou then
unlock the vehicle centrally, the trunk
remains locked and cannot be opened.
X Close the trunk lid.
X Take the mechanical key out of the
SmartKey (Y page 84). X
Insert the mechanical key into the trunk lid
lock as far as the stop.
X Turn the mechanical key clockwise from
position 0005to position 0006.
X Remove the mechanical key.
X Insert the mechanical key into the
SmartKey. Unlocking the trunk (mechanical key)
! The trunk lid swings upwards when
opened. Therefore, make sure that there is
sufficient clearance above the trunk lid.
If the trunk cannot be unlocked with the
SmartKey or KEYLESS-GO, use the
mechanical key.
If you use the mechanical key to unlock and
open the trunk lid, the anti-theft alarm system
will be triggered (Y page 79).
X Take the mechanical key out of the
SmartKey (Y page 84).
X Insert the mechanical key into the trunk lid
lock as far as the stop. 94
TrunkOpening/closing