2012 MERCEDES-BENZ C-Class SEDAN key

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 298).
or
XJump-start the vehicle ( Y page 301).
or
XConsult a qualified specialist workshop.The engine cannot be
started using the
SmartKey.The steering lock is mechanically blocked.XRemove the SmartKey and reinsert it into the ignition lock. While
doing this, turn the steering wheel in both directions.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.
Doors77Opening/closingZ

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
Unlocking and opening doors from
inside
You can open a door from inside the vehicle
even if it has been locked. You can only open
the rear doors from inside the vehicle if they
are not secured by the child-proof locks
( Y page 57).
Only open the door when the traffic situation
permits.
If the vehicle was previously locked with the
SmartKey or with KEYLESS-GO, opening the
vehicle from the inside will activate the anti-
theft alarm system. Switch off the alarm
( Y page 67).
XPull door handle ;.
If the door is locked, locking knob : pops
up. The door is unlocked and can be
opened.
Centrally locking and unlocking the
vehicle from the inside
You can centrally lock or unlock the vehicle
from the inside.
The central locking/unlocking button does
not lock or unlock the fuel filler flap.
i You cannot unlock the vehicle centrally
from the inside if the vehicle has been
locked with the SmartKey or KEYLESS-GO.
i It is only possible to lock the vehicle
centrally if the front-passenger door is
closed.XTo unlock: press button :.XTo lock: press button ;.
If the front-passenger door is closed, the
vehicle locks.
You can open a front door from inside the
vehicle even if it has been locked. Only open
the door when the traffic situation permits.
If the vehicle has been locked with the central
locking button:
R and the SmartKey is set to its factory
setting, the entire vehicle is unlocked if a
front door is opened from the inside
R and the SmartKey is set to an individual
setting, only the front door that is opened
from inside the vehicle is unlocked.
If the vehicle has been locked centrally with
the SmartKey or with KEYLESS-GO, it is not
unlocked when the release button for the
central locking is used.
Automatic locking feature
The vehicle locks automatically when the
ignition is switched on and the wheels of the
78DoorsOpening/closing

vehicle are turning at a speed of more than
9 mph (15 km/h).
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.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 208).
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 67).
XTake the mechanical key out of the
SmartKey ( Y page 73).XInsert the mechanical key into the lock of
the driver's door as far as it will go.XTurn the mechanical key counterclockwise
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, the rear
doors and the trunk lid.XPress the locking button ( Y page 78).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 73).XInsert the mechanical key into the lock of
the driver's door as far as it will go.Doors79Opening/closingZ

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.
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.
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
GWARNING
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 5.90 ft (1.80 m) above the
ground is necessary.
The trunk lid can be:
R opened and closed manually from outside
R opened automatically from outside
R opened automatically from inside
R locked separately
80TrunkOpening/closing

Runlocked with the mechanical key
R opened with the emergency release button
Opening and closing manually
Opening
XPress the % button on the SmartKey.XPull handle :.XRaise the trunk lid.
Closing
GWARNING
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.
XPull the trunk lid down using recess :.XIf necessary, lock the vehicle with
the & button on the SmartKey(Y page 70) or with KEYLESS-GO
( Y page 71).
i
If a KEYLESS-GO key is detected in the
trunk, the trunk lid cannot be locked and
then opens again.
Opening automatically from outside
Important safety notes
GWARNING
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 5.90 ft (1.80 m) above the
ground is necessary.
Opening
You can open the trunk lid automatically
using the SmartKey or the handle in the trunk
lid.
XPress and hold the F button on the
SmartKey until the trunk lid opens.
or
XWhen the trunk is unlocked, pull the trunk
lid handle and let it go again immediately.
Closing
Opening automatically from the
inside
GWARNING
Make sure the trunk lid is closed when the
engine is running and while driving. Among
other dangers, deadly carbon monoxide (CO)
Trunk81Opening/closingZ

gases may enter the vehicle interior resulting
in unconsciousness and death.
You can open the trunk lid from the driver's
seat when the vehicle is stationary and
unlocked.XTo open: press the upper section of remote
operating switch for trunk lid : until the
trunk lid opens.
Locking the trunk separately
You can lock the trunk separately. If you then
unlock the vehicle centrally, the trunk
remains locked and cannot be opened.
XClose the trunk lid.XTake the mechanical key out of the
SmartKey ( Y page 73).XInsert the mechanical key into the trunk lid
lock as far as the stop.XTurn the mechanical key clockwise from
position 1 to position 2.XRemove the mechanical key.XInsert 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 67).
XTake the mechanical key out of the
SmartKey ( Y page 73).XInsert the mechanical key into the trunk lid
lock as far as the stop.XTurn the mechanical key counter-clockwise
from position 1 as far as it will go to
position 2.
The trunk is unlocked.XTurn the mechanical key back to position
1 and remove it.XInsert the mechanical key into the
SmartKey.
Trunk emergency release
You can open the trunk lid from inside the
vehicle with the emergency release button.
82TrunkOpening/closing

XBriefly press emergency release
button :.
The trunk lid unlocks and opens.
The trunk lid can be unlocked and opened
with the trunk lid emergency release when
the vehicle is stationary or while driving.
Trunk lid emergency release light:
R emergency release button : flashes for
30 minutes after the trunk lid is opened.
R emergency release button : flashes for
60 minutes after the trunk lid is closed.
The trunk lid emergency release does not
open the trunk lid if the battery is
disconnected or discharged.
Side windows
Important safety notes
GWARNING
When opening or closing the door windows,
make sure that there is no danger of anyone
being harmed by the opening/closing
procedure.
The door windows are equipped with
automatic operation and the anti-entrapment
feature. If in automatic mode a door window
encounters an obstruction that blocks its
path, the anti-entrapment feature will stop the
door window and open it slightly.
The door windows operate differently when
the switch is pulled. See the "Problems with
door windows" section for details.
The closing of the door windows can be
immediately halted by releasing the switch or,
if the switch was pulled past the resistance
point and released, by either pressing or
pulling the respective switch.
If a door window encounters an obstruction
that blocks its path in a circumstance where
you are closing the windows by pressing and
holding the & button on the SmartKey or
by pressing and holding the lock button
(vehicles with KEYLESS-GO) on an outside
door handle, the anti-entrapment feature will
not operate.
Activate the override switch when children
are riding in the back seats of the vehicle. The
children may otherwise injure themselves,
e.g. by becoming trapped in the door window
opening.GWARNING
Do not keep any part of your body up against
the window pane when opening a window. The
downward motion of the pane may pull that
part of your body down between the window
pane and the door frame and trap it there. If
there is a risk of entrapment, release the
switch and pull it to close the window.
Opening and closing the side
windows
:Front left;Front right=Rear right?Rear leftSide windows83Opening/closingZ

The switches for all side windows are located
on the driver's door. There is also a switch on
each door for the corresponding side window.
The switches on the driver's door take
precedence.
i The side windows cannot be operated
from the rear when the override feature for
the side windows is activated ( Y page 57).XTurn the SmartKey to position 1 or 2 in the
ignition lock.XTo open: press the corresponding switch.XTo close: pull the corresponding switch.
i
If you press the switch beyond the point
of resistance, an automatic opening/
closing process is started in the
corresponding direction. You can stop
automatic operation by operating the
switch again.
i You can continue to operate the side
windows after you switch off the engine or
remove the SmartKey. This function is
available for up to five minutes or until the
driver's or front-passenger door is opened.
Convenience opening feature
You can ventilate the vehicle before you start
driving. To do this, the key is used to carry out
the following functions simultaneously:
R unlock the vehicle
R open the side windows
R open the sliding sunroof or the panorama
roof with power tilt/sliding panel and the
roller sunblinds
i The convenience opening feature can
only be operated using the SmartKey. The
SmartKey must be close to the driver's
door handle.
XPoint the tip of the SmartKey at the driver's
door handle.XPress and hold the % button until the
side windows and the sliding sunroof or thepanorama roof with power tilt/sliding
panel are in the desired position.
If the roller sunblinds of the panorama roof
with power tilt/sliding panel are closed, the
roller sunblinds are opened first.
XPress and hold the % button again until
the panorama roof with power tilt/sliding
panel is in the desired position.XTo interrupt convenience opening:
release the % button.
Convenience closing
General notes
When you lock the vehicle, you can
simultaneously:
R close the side windows
R close the sliding sunroof or the panorama
roof with power tilt/sliding panel
On vehicles with a panorama roof with power
tilt/sliding panel, you can then close the
roller sunblinds.
GWARNING
When closing the door windows and the
sliding sunroof or panorama roof with power
tilt/sliding panel, make sure that there is no
danger of anyone being harmed by the closing
procedure.
If potential danger exists, proceed as follows:
R Release the & button to stop the closing
procedure. To open, press and hold the
% button. To continue the closing
procedure after making sure that there is
no danger of anyone being harmed by the
closing procedure, press and hold the
& button.
Vehicles with KEYLESS-GO:
R Release the sensor surface on the outside
door handle to stop the closing procedure.
R Immediately pull on the same outside door
handle and hold firmly. The door windows
and the sliding sunroof or panorama roof
84Side windowsOpening/closing