change key battery MERCEDES-BENZ S-Class 2011 W221 Owner's Manual

Vehicle equipment
i This manual describes all the standard
and optional equipment of your vehicle
which was available at the time of
purchase. Country-specific differences are
possible. Bear in mind that your vehicle
may not feature all functions described
here. This also refers to safety-related
systems and functions.
SmartKey
Important safety notes
GWarning!
When leaving the vehicle, always remove the
SmartKey from the starter switch. Always
take the SmartKey with you and lock the
vehicle. Do not leave children unattended in
the vehicle, even if they are secured in a child
restraint system, or with access to an
unlocked vehicle. A child's unsupervised
access to a vehicle could result in an accident
and/or serious personal injury. The children
could
R injure themselves on parts of the vehicle
R be seriously or fatally injured through
excessive exposure to extreme heat or cold
R injure themselves or cause an accident with
vehicle equipment that can be operated
even if the SmartKey is removed from the
starter switch or removed from the vehicle,
such as seat adjustment, steering wheel
adjustment, or the memory function
If children open a door, they could injure other
persons or get out of the vehicle and injure
themselves or be injured by following 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 the child could be burned by these
parts.
GWarning
Do not carry heavy or hard objects in the
passenger compartment 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
General information
If you cannot open or lock the vehicle with the
SmartKey, either the battery in the SmartKey
is empty, the SmartKey is faulty, or the starter
battery is discharged.
XCheck the battery in the SmartKey and
replace it if necessary ( Y page 80).XUnlock the driver's door with the
mechanical key ( Y page 84).XLock the vehicle ( Y page 84).XHave the starter battery and battery
contacts checked by 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 regulations. Operation is subject to
the following conditions:
1. This device must not cause any harmful
interference, and
2. This device must be able to
accommodate interference that is
received, including interference which
could cause unwanted functions.
76SmartKeyOpening and closing

X To unlock the vehicle: pull the door
handle.XTo lock the vehicle: touch sensor
surface :.
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 80) flashes twice.
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 : pull the door
handle on the driver's door.XTo unlock centrally: pull the door handle
on the front-passenger door or on the rear
doors.XTo lock centrally: touch 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 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 73).
There are several ways to turn off the alarm:
XPress the % or & button on the
SmartKey.
or
XInsert the SmartKey into the ignition lock.
or
XPress 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.
Removing the mechanical key
XPush release catch : in the direction of
the arrow and at the same time, remove
mechanical key ; from the SmartKey.
SmartKey battery
Important safety notes
It is advisable to have batteries replaced at a
qualified specialist workshop, e.g. at an
authorized Mercedes-Benz Center.
SmartKey79Opening and closingZ

Problems with the SmartKeyProblemPossible causes/consequences and M SolutionsYou cannot lock or
unlock the vehicle
using the SmartKey.The SmartKey battery is discharged or nearly discharged.XPoint the tip of the SmartKey at the driver's door handle from a
distance of approximately 1.5 ft (50 cm) and try to unlock or
lock the vehicle again.
If this does not work:
XCheck the SmartKey battery and replace it if necessary
( Y page 80).XLock ( Y page 84) or unlock ( Y page 84) the vehicle using
the mechanical key.The SmartKey is faulty.XLock ( Y page 84) or unlock ( Y page 84) the vehicle using
the mechanical key.XHave the SmartKey checked at a qualified specialist workshop.You can no longer lock
or unlock the vehicle
using KEYLESS-GO.KEYLESS-GO is in standby mode because the vehicle has not been
unlocked for an extended period.XPull the door handle twice and then insert the SmartKey into the
ignition lock.There is a malfunction with KEYLESS-GO.XLock/unlock the vehicle using the remote control function of
the SmartKey. Point the tip of the SmartKey at the driver's door
handle from close range and press the %/& button.XHave the SmartKey checked at a qualified specialist workshop.There is interference from a powerful source of radio waves.XLock/unlock the vehicle using the remote control function of
the SmartKey. Point the tip of the SmartKey at the driver's door
handle from close range and press the %/& button.You have lost the
SmartKey.XHave the SmartKey canceled at an authorized Mercedes-Benz
Center.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.SmartKey81Opening and closingZ

ProblemPossible causes/consequences and M SolutionsThe engine cannot be
started using the
SmartKey.The on-board voltage is too low.XRemove the SmartKey and reinsert it into the ignition lock.XStart the engine within 30 seconds of inserting the SmartKey
into the ignition lock.XRepeat if necessary.
If the engine does not start after several attempts:
XCheck the starter battery and charge it if necessary
( Y page 468).
or
XJump-start the vehicle ( Y page 471).
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 starter switch. Always
take the SmartKey with you and lock the
vehicle. Do not leave children unattended in
the vehicle, even if they are secured in a child
restraint system, or with access to an
unlocked vehicle. A child's unsupervised
access to a vehicle could result in an accident
and/or serious personal injury. The children
could
R injure themselves on parts of the vehicle
R be seriously or fatally injured through
excessive exposure to extreme heat or cold
R injure themselves or cause an accident with
vehicle equipment that can be operated
even if the SmartKey is removed from the
starter switch or removed from the vehicle,
such as seat adjustment, steering wheel
adjustment, or the memory function
If children open a door, they could injure other
persons or get out of the vehicle and injure
themselves or be injured by following 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 the child could be burned by these
parts.GWarning
Do not carry heavy or hard objects in the
passenger compartment 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
82DoorsOpening and closing

ECOMAND: e.g. to select a station from
presets, select a track, enter directly,
enter a phone number. Rear Seat
Entertainment System: to select a
track, enter directlyFTo leave the menu (back)XPoint the remote control at the
corresponding screen and execute the
functions by pressing the corresponding
button.
i The remote control's function may be
restricted depending on the angle at which
it is pointed at the respective screen.
Selecting the screen for the remote
control
XTurn thumbwheel = until the desired
display is highlighted in the window.
Switching the screen on/off (Rear Seat
Entertainment System only)
If the key is in position 0 or 1 in the ignition
lock (see vehicle Operator's Manual), or the
key is not inserted, the screens in the rear will
switch off after 30 minutes. Before the
screens switch off, they show a message to
this effect.
You can switch the screens back on,
However, this will discharge the starter
battery.
XPoint the remote control at the rear-
compartment screen which has been
selected for remote operation.XPress button : on the remote control.
The respective rear screen switches on or
off.
i You can only switch the screens on using
the remote control if the ignition is
switched on.
Switching button lighting on/offXPress button ; on the remote control.
Depending on the previous status, the
button lighting is switched on or off.
i If you do not use the remote control for
about 15 seconds, the button lighting
switches off automatically.
Mute
XPress button B on the remote control.
The sound is switched on/off.
Adjusting the volume
This function is available for COMAND and for
the Rear Seat Entertainment System in
conjunction with corded headphones.
XPress one of buttons C on the remote
control.
The volume of the currently selected audio
or video source changes.
For COMAND, you can also adjust the
volume for phone calls and navigation
announcements.
Selecting a menu/menu item and
confirming your selection
XSelect a menu/menu item using the
=;9: buttons and press
the 9 button to confirm.124At a glanceCOMAND

Switch the reading lamp off=Interior lighting
Interior lighting control
Important notes
In order to prevent the vehicle's battery from
discharging, the interior lighting functions are
automatically deactivated after some time
except for when the key is in position 2 in the
ignition lock.
Automatic interior lighting control
XTo switch on/off: press the | button.
The OFF indicator lamp shows whether the
automatic interior lighting control is
deactivated (indicator lamp on) or
activated (indicator lamp off).
The interior lighting automatically switches
on if you:
R unlock the vehicle
R open a door
R remove the key from the ignition lock
The interior light is activated for a short while
when the key is removed from the ignition
lock. You can activate this delayed switch-off
using COMAND ( Y page 259).
Manual interior lighting control
XTo switch the front interior lighting on/
off: press the c button.XTo switch the rear interior lighting on/
off: press the u button.XTo switch the reading lamps on/off:
press the p button.Changing bulbs
Important safety notes
Xenon bulbs
If your vehicle is equipped with Xenon bulbs,
you can recognize this by the following: the
cone of light from the Xenon bulbs moves
from the top to the bottom and back again
when you start the engine. For this to be
observed, the lights must be switched on
before starting the engine.
GWarning
Xenon bulbs carry a high voltage. You could
get an electric shock and be seriously or even
fatally injured if you touch the electric
contacts on Xenon bulbs. Therefore, never
remove the cover from Xenon bulbs.
Do not change Xenon bulbs yourself, but have
them replaced at a qualified specialist
workshop which has the necessary specialist
knowledge and tools to carry out the work
required.
Mercedes-Benz recommends that you use an
authorized Mercedes-Benz Center for this
purpose. In particular, work relevant to safety
or on safety-related systems must be carried
out at a qualified specialist workshop.
Bulbs and lamps are an important aspect of
vehicle safety. You must therefore make sure
that these function correctly at all times.
Have the headlamp setting checked regularly.
Other bulbs
GWarning!
Bulbs and lamps can be very hot. You should
therefore allow them to cool down before you
change them. Otherwise, you could be burned
if you touch them.
Keep bulbs out of the reach of children.
Otherwise, they could damage the bulbs, for
example, and injure themselves.
278Changing bulbsLights and windshield wipers

SmartKeyDisplay messagesPossible causes/consequences and M SolutionsÂ
Key Does Not
Belong to VehicleYou have put the wrong SmartKey in the ignition lock.XUse the correct SmartKey.Â
Take Your Key From
IgnitionThe 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
Replace Key BatteryThe batteries of the KEYLESS-GO key are discharged.XChange the batteries ( Y page 79).Â
Don't Forget Your
KeyThe display message is displayed for a maximum of 60 seconds
and is just a reminder.
You have opened the driver's door with the engine switched off.
The KEYLESS-GO key is not in the ignition lock.XTake the KEYLESS-GO key with you when leaving the vehicle.Â
Key Not Detected
(red display message)The KEYLESS-GO key 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.XEngage the parking brake.XLocate the KEYLESS-GO key.The KEYLESS-GO key is not detected while the engine is running
because there is interference from a strong source of radio waves.
A warning tone also sounds.XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.XEngage the parking brake.XOperate the vehicle with the KEYLESS-GO key in the ignition
lock if necessary.Display messages411On-board computer and displaysZ