
Rwhen the external door handles are
touched
Rduring convenience closing
XTo unlock the vehicle:touch the inner
surface of the door handle.
XTo lock the vehicle: touch sensor sur-
face :or;.
Make sure that you do not touch the inner
surface of the door handle.
XConvenience closing feature: touch
recessed sensor surface ;for an exten-
ded period.
Further information on the convenience
closing feature (
Ypage 99).
XTo unlock the tailgate: pull the tailgate
handle.
Deactivating and activating
If you do not intend to use a SmartKey for an
extended period of time, you can deactivate
the KEYLESS-GO function of the SmartKey.
The SmartKey will then use very little power,
thereby conserving battery power. For the
purposes of activation/deactivation, the
vehicle must not be nearby.
XTo deactivate: press the&button on
the SmartKey twice in rapid succession.
The battery check lamp of the SmartKey
flashes twice briefly and lights up once, then KEYLESS-GO is deactivated
(
Ypage 86).
XTo activate:
press any button on the
SmartKey.
or
XInsert the SmartKey into the ignition lock.
KEYLESS-GO and all of its associated fea-
tures are available again.
KEYLESS-GO start function
Bear in mind that the engine can be started by
any of the vehicle occupants if there is a
SmartKey in the vehicle.
Changing the settings of the locking
system
You can change the settings of the locking
system. This means that only the driver's door
and the fuel filler flap are unlocked when the
vehicle is unlocked. This is useful if you fre-
quently travel on your own.
XTo change the setting: press and hold the
% and& buttons simultaneously for
approximately six seconds until the battery
indicator lamp flashes twice (
Ypage 86).
If the setting of the locking system is changed
within the signal range of the vehicle, press-
ing the &or% button:
Rlocks or
Runlocks the vehicle
The SmartKey now functions as follows:
XTo unlock: press the%button once.
XTo unlock centrally: press the%but-
ton twice.
XTo lock: press the &button.
84SmartKey
Opening and closing

The KEYLESS-GO function is changed as fol-
lows:
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 sur-
face 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.
XTo restore the factory settings: press
and hold the %and& buttons simul-
taneously for approximately six seconds
until the battery check lamp flashes twice
(
Ypage 86).
Mechanical key
General notes
If the vehicle can no longer be locked or
unlocked with the SmartKey or KEYLESS-GO,
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. Switch off the alarm
(
Ypage 78).
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 into the ignition lock.
Removing the mechanical key
XPush release catch :in the direction of
the arrow and at the same time remove
mechanical key ;from the SmartKey.
Further information:
RUnlocking the driver's door (Ypage 90)
RUnlocking the cargo compartment
(
Ypage 97)
RLocking the vehicle (Ypage 91)
Inserting the mechanical key
XPush mechanical key ;completely into
the SmartKey until it engages and release
catch :is back in its basic position.
SmartKey battery
Important safety notes
GWARNING
Batteries contain toxic and corrosive substan- ces. If batteries are swallowed, it can result in
severe health problems. There is a risk of fatalinjury.
Keep batteries out of the reach of children. If
a battery is swallowed, seek medical attention
immediately.
HEnvironmental note
Batteries contain dangerous
substances. It is against the
law to dispose of them with
the household rubbish. They
must be collected separately and recycled to protect the
environment.
Dispose of batteries in an
environmentally friendly
manner. Take discharged
batteries to a qualified spe-
cialist workshop or a special
collection point for used bat-
teries.
The SmartKey batteries contain perchlorate
material, which may require special handling
SmartKey85
Opening and closing
Z

and regard for the environment. National
guidelines must be observed during disposal.
In California, seewww.dtsc.ca.gov/
HazardousWaste/Perchlorate/
index.cfm.
Mercedes-Benz recommends that you have
the batteries replaced at a qualified specialist
workshop.
Checking the battery
XPress the &or% button.
The battery is working properly if battery
check lamp :lights up briefly.
The battery is discharged if battery check
lamp :does not light up briefly.
XChange the battery (Ypage 86).
If the SmartKey battery is checked within the
signal reception range of the vehicle, pressing
the & or% button:
Rlocks or
Runlocks the vehicle
iYou can get a battery at any qualified spe-
cialist workshop.
Replacing the battery
You require a CR 2025 3 V cell battery.
XTake the mechanical key out of the Smart-
Key (
Ypage 85).
XPress mechanical key ;into the SmartKey
opening in the direction of the arrow until
battery compartment cover :opens. Do
not hold battery compartment cover :
closed while doing so.
XRemove battery compartment cover :.
XRepeatedly tap the SmartKey against your
palm until battery=falls out.
XInsert the new battery with the positive ter-
minal facing upwards. Use a lint-free cloth
to do so.
XMake sure that the surface of the battery is
free of lint, grease and other contaminants.
XInsert the front tabs of battery compart-
ment cover :into the housing first and
then press to close it.
XInsert mechanical key ;into the Smart-
Key.
XCheck the function of all SmartKey buttons
on the vehicle.
86SmartKey
Opening and closing

ProblemPossible causes/consequences andMSolutions
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
(
Ypage 363).
or
XJump-start the vehicle (Ypage 365).
or
XConsult 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.
XUnlock the vehicle and try to start the vehicle again.
The SmartKey battery is discharged or nearly discharged.
XCheck the SmartKey battery (Ypage 86) and replace it if nec-
essary (
Ypage 86).
If this does not work:
XStart your vehicle with the SmartKey in the ignition lock.
There is interference from a powerful source of radio waves.
XStart your vehicle with the SmartKey in the ignition lock.
You have lost a Smart-
Key.XHave the SmartKey deactivated at a qualified specialist work-
shop.
XReport the loss immediately to the vehicle insurers.
XIf necessary, have the locks changed as well.
You have lost the
mechanical key.XReport the loss immediately to the vehicle insurers.
XIf necessary, have the locks changed as well.
88SmartKey
Opening and closing

The synchronization function deactivates if
the settings for the front-passenger side are
changed.
Defrosting the windshield
General notes
You can use this function to defrost the wind-
shield or to clear a fogged up windshield or
front side windows on the inside.
Switch off the "Windshield defrosting" func-
tion as soon as the windshield is clear again.
Switching the "Windshield defrosting"
function on or off
XTurn the SmartKey to position 2in the igni-
tion lock (
Ypage 153).
XTo activate: press the¬rocker switch
on the front control unit up or down.
The indicator lamp above the ¬rocker
switch lights up. The current climate con-
trol settings are deactivated.
The climate control system switches to the
following functions:
Rhigh airflow
Rhigh temperature
Rair distribution to the windshield and
front side windows
Rair-recirculation mode off
iIf necessary, the "Cooling with air dehu-
midification" function is activated. In this
case, the indicator lamp above the
¿ rocker switch remains switched off.
XTo deactivate: press the¬rocker
switch up or down.
The indicator lamp above the ¬rocker
switch goes out. The previously selected
settings are restored. Air-recirculation
mode remains deactivated.
or
XPress the top or bottom section of the Ã
rocker switch.
Defrosting the windows
Windows fogged up on the inside
XActivate the cooling with air dehumidifica-
tion function with the ¿rocker switch.
or
XActivate the cooling with air dehumidifica-
tion function via Audio 20 or COMAND (see
the separate operating instructions).
XSwitch on automatic mode using the Ã
rocker switch.
XIf the windows continue to fog up, activate
the "Windshield defrosting" function using
the ¬ rocker switch.
iYou should only select this setting until
the windshield is clear again.
Windows fogged up on the outside
XActivate the windshield wipers.
XSwitch on automatic mode using the Ã
rocker switch.
iIf you clean the windows regularly, they
do not fog up so quickly.
Rear window defroster
General notes
The rear window defroster has a high current draw. You should therefore switch it off as
soon as the rear window is clear. Otherwise,
the rear window defroster switches off auto-
matically after several minutes.
If the battery voltage is too low, the rear win-
dow defroster may switch off.
Switching on/off
XTurn the SmartKey to position 2in the igni-
tion lock (
Ypage 153).
XPress the ¤rocker switch up or down.
The indicator lamp above the ¤rocker
switch lights up or goes out.
146Operating the climate control systems
Climate control

SmartKey
Display messagesPossible causes/consequences andMSolutions
Â
Key Does Not
Belong to Vehicle
You have put the wrong SmartKey in the ignition lock.
XUse the correct SmartKey.
Â
TakeYourKeyfrom
Ignition
The SmartKey is in the ignition lock.
XRemove the SmartKey.
Â
Obtain a New Key
The SmartKey needs to be replaced.
XVisit a qualified specialist workshop.
Â
ReplaceKeyBattery
The SmartKey battery is discharged.
XChange the batteries (Ypage 86).
Â
Don't Forget Your
Key
The SmartKey is not in the ignition lock. You have opened the
driver's door with the engine switched off.
This display message is displayed for a maximum of 60 seconds
and is simply a reminder.
XTake the SmartKey with you when you leave the vehicle.
Â
Key Not Detected
(white display mes-
sage)
The SmartKey is currently undetected.
XChange the location of the SmartKey in the vehicle.
If the SmartKey still cannot be detected:
XInsert the SmartKey into the ignition lock and turn it to the
desired position.
Â
Key Not Detected
(red display message)
The SmartKey is not in the vehicle.
A warning tone also sounds.
If the engine is switched off, you can no longer lock the vehicle
centrally or start the engine.
XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
XSecure the vehicle against rolling away (Ypage 172).
XLocate the SmartKey.
XPress aon the steering wheel to confirm the display mes-
sage.
290Display messages
On-board computer and displays