
XTo activate/deactivate: activate or
deactivate PRE-SAFE ®
Brake in the on-
board computer ( Y page 207).
The Ä symbol appears in the
multifunction display as long as the HOLD
function is not activated ( Y page 166).
On vehicles with Active Parking Assist, the
Ä symbol is displayed when
transmission position P is selected or if you
drive faster than 22 mph(35 km/h).
For PRE-SAFE ®
Brake to assist you when
driving, the radar sensor system must be
switched on ( Y page 211) and operational.
Following damage to the front end of the
vehicle, have the configuration and operation
of the radar sensors checked at a qualified
specialist workshop. This also applies to
collisions at slow speeds where there is no
visible damage to the front of the vehicle.
Theft deterrent locking systems
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.
XTo activate with the SmartKey: remove
the SmartKey from the ignition lock.XTo activate with KEYLESS-GO: switch the
ignition off and open the driver's door.XTo deactivate: switch on the ignition.
i
The immobilizer is always deactivated
when you start the engine.
In the event that the engine cannot be
started when the starter battery is fully
charged, the immobilizer may be faulty.
Contact an authorized Mercedes-Benz
Center or call 1-800-FOR-MERCedes (in
USA) or 1-800-387-0100 (in Canada).
ATA (Anti-Theft Alarm system)
A visual 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 emergency call system
mbrace (USA only) or TELE AID (Canada
only) initiates a call to the Customer
Assistance 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.XTo arm: lock the vehicle with the SmartKey
or KEYLESS-GO.
Indicator lamp : flashes. The alarm
system is armed after approximately 15
seconds.XTo deactivate: unlock the vehicle with the
SmartKey or KEYLESS-GO.Theft deterrent locking systems69SafetyZ

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 You can find information on qualified
specialist workshops here ( Y page 22).
SmartKey
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
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 could 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 information
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.
XCheck the battery in the SmartKey and
replace it if necessary ( Y page 76).XUnlock the driver's door using the
mechanical key ( Y page 81).XLock the vehicle using the mechanical key
( Y page 81).XHave the starter battery and battery
contacts checked at an authorized
Mercedes-Benz Center.
If the SmartKey is faulty, contact Roadside
Assistance or an authorized Mercedes-Benz
Center.
SmartKey functions
General notes
i USA only:
This device complies with Part 15 of the
FCC Rules. Operation is subject to the
following two conditions:
1. This device may not cause harmful
interference, and
2. this device must accept any interference
received, including interference that may
cause undesired operation.
72SmartKeyOpening/closing

Any unauthorized modification to this
device could void the user’s authority to
operate the equipment.
The Product label with FCC ID and IC
certification number can be found in the
battery case of the SmartKey.
i Canada only:
This device complies with RSS-210 of
Industry Canada. Operation is subject to
the following two conditions:
1. This device may not cause interference,
and
2. this device must accept any interference
received, including interference that may
cause undesired operation of the device.
Any unauthorized modification to this
device could void the user’s authority to
operate the equipment.
The Product label with FCC ID and IC
certification number can be found in the
battery case of the SmartKey.
Locking and unlocking centrally
The SmartKey centrally locks/unlocks:
R the doors
R the trunk lid
R the fuel filler flap
:& To lock the vehicle;F To unlock the trunk lid=% To unlock 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 the on-board
computer ( Y page 210).
You can also set an audible signal to confirm
that the vehicle has been locked or unlocked.
The audible signal can be activated and
deactivated using the on-board computer
( Y page 211).XTo unlock centrally: press the %
button.
If you do not open the vehicle within
approximately 40 seconds of unlocking:
R the vehicle is locked again.
R the theft deterrent locking system is armed
again.
XTo lock centrally: press the & button.
KEYLESS-GO
General notes
i USA only:
This device complies with Part 15 of the
FCC Rules. Operation is subject to the
following two conditions:
1. This device may not cause harmful
interference, and
2. this device must accept any interference
received, including interference that may
cause undesired operation.
Any unauthorized modification to this
device could void the user’s authority to
operate the equipment.
The product label with FCC ID and IC
certification number can be found in the
battery case of the SmartKey.
i Canada only:
This device complies with RSS-210 of
Industry Canada. Operation is subject to
the following two conditions:
1. This device may not cause interference,
and
SmartKey73Opening/closingZ

2. this device must accept any interference
received, including interference that may
cause undesired operation of the device.
Any unauthorized modification to this
device could void the user’s authority to
operate the equipment.
The product label with FCC ID and IC
certification number can be found in the
battery case of the SmartKey.
Important notes on the use of KEYLESS-
GO
R The KEYLESS-GO key can be used like a
conventional key.
R You can combine KEYLESS-GO functions
with those of a conventional key, e.g.
unlock with KEYLESS-GO and lock with the
& button.
R Always carry your KEYLESS-GO key on your
person.
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 When locking and unlocking using
KEYLESS-GO, the distance between the
SmartKey and the corresponding door
handle must not exceed 3 ft (1 m).
R If the KEYLESS-GO key is removed from the
vehicle, it is possible that the system may
not recognize the SmartKey. The vehicle
can then not be locked or started using
KEYLESS-GO.
R If the KEYLESS-GO key has been removed
from the vehicle, e.g. if a passenger leaves
the vehicle with a KEYLESS-GO key:
- if the Start/Stop button is pressed or if
an attempt is made to lock the vehicle
using the outer door handle, the Key
Not Detected message will appear in
the multifunction display.
- while the engine is running, the red Key
Not Detected message will appear in
the multifunction display as you pull
away. Find the KEYLESS-GO key and
change its position in the vehicle. Carry
the KEYLESS-GO key in your shirt pocket,
for example.
R If you have started the engine with the
Start/Stop button, you can switch it off
again by:
- pressing the Start/Stop button again
- inserting the KEYLESS-GO key into the
ignition lock if the vehicle is stationary
and the automatic transmission is in park
position P.
R You could unlock the vehicle by mistake if
the distance between the KEYLESS-GO key
and the vehicle is less than 3 ft (1 m) and:
- an exterior door handle is hit by a water
jet
or
- you clean an exterior door handle.
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.X To unlock the vehicle: touch the inner
surface of the door handle.XTo lock the vehicle: touch sensor
surface :.XConvenience closing feature: touch
recessed sensor surface ; for an
extended period ( Y page 87).74SmartKeyOpening/closing

If you pull on the handle of the trunk lid, only
the trunk of the vehicle is unlocked.
Changing the settings of the locking
system
You can change the setting of the locking
system in such a way that only the driver's
door and the fuel filler flap are unlocked. This
is useful if you frequently travel on your own.
XTo change the setting: press and hold
down the % and & buttons
simultaneously for approximately six
seconds until the battery check lamp
( Y page 76) flashes twice.
i
If the setting of the locking system is
changed within the signal range of the
vehicle, pressing the & or % button
locks or unlocks the vehicle.
The SmartKey now functions as follows:
XTo unlock the driver's door: press the
% button once.XTo unlock centrally: press the %
button twice.XTo lock centrally: press the & button.
The KEYLESS-GO function is changed as
follows:
XTo unlock the driver's door: touch the
inner surface of the door handle on the
driver's door.XTo unlock centrally: touch the inner
surface of the door handle on the front-
passenger door or the rear door.XTo lock centrally: touch the outer sensor
surface on one of the door handles.
Restoring the factory settings
XPress the % and & buttons
simultaneously for approximately six
seconds until the battery check lamp
flashes twice.Mechanical key
General notes
If the vehicle can no longer be locked or
unlocked with the SmartKey, use the
mechanical key.
If you use the mechanical key to unlock and
open the driver's door or the trunk lid, the
anti-theft alarm system will be triggered
( Y page 69).
There are several ways to turn off the alarm:
XTo turn the alarm off with the
SmartKey: press the % or & button
on the SmartKey.
or
XInsert the SmartKey into the ignition lock.
or
XTo deactivate the alarm with KEYLESS-
GO: press the Start/Stop button in the
ignition lock. The SmartKey must be in the
vehicle.
or
XLock or unlock the vehicle using KEYLESS-
GO. The SmartKey must be outside the
vehicle.
If you unlock the vehicle using the mechanical
key, the fuel filler flap will not be unlocked
automatically.
XTo unlock the fuel filler flap: insert the
SmartKey in the ignition lock.
Removing the mechanical key
SmartKey75Opening/closingZ

ProblemPossible causes/consequences and M SolutionsThe 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 302).
or
XJump-start the vehicle ( Y page 305).
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 trunk 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
Doors79Opening/closingZ

XTo deactivate: press and hold button :
for about five seconds until a tone sounds.XTo 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 211).
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
to position 1.
The door is unlocked.XTurn the mechanical key back and remove
it.XInsert 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.
XOpen the driver's door.XClose the front-passenger door and the
trunk lid.XPress the locking button ( Y page 80).XCheck 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.XClose the driver's door.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 clockwise as far
as it will go to position 1.XTurn the mechanical key back and remove
it.XMake sure that the doors and the trunk lid
are locked.XInsert the mechanical key into the
SmartKey.Doors81Opening/closingZ

iIf 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.
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 trunk 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 accidentGWARNING
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.
! 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 5.41 ft (1.65 m) above the
ground is necessary.
The trunk lid can be:
R opened and closed manually from outside
R opened and closed automatically from
outside
R opened automatically from inside
R locked separately
R unlocked with the mechanical key
R opened with the emergency release button
Opening and closing manually
Opening
XPress the % button on the SmartKey.82TrunkOpening/closing