trunk MERCEDES-BENZ C-Class SEDAN 2012 W204 User Guide

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

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

High-beam headlamps (halogen
headlamps)XSwitch off the lights.XOpen the hood.XTurn housing cover : counter-clockwise
and pull it out.XTurn bulb holder ; counter-clockwise and
pull it out.XTake the bulb out of bulb holder ;.XInsert the new bulb into bulb holder ;.XInsert bulb holder ; into the lamp and turn
it clockwise.XAlign housing cover : and turn it
clockwise until it engages.
Parking lamps/standing lamps
(halogen headlamps)
XSwitch off the lights.XOpen the hood.XTurn housing cover : counter-clockwise
and pull it out.XPull out bulb holder ;.XTake the bulb out of bulb holder ;.XInsert the new bulb into bulb holder ;.XInsert bulb holder ;.XAlign housing cover : and turn it
clockwise until it engages.
Cornering light function (Bi-Xenon
headlamps)
XSwitch off the lights.XOpen the hood.XTurn housing cover : counter-clockwise
and pull it out.XTurn bulb holder ; counter-clockwise and
pull it out.XTake the bulb out of bulb holder ;.XInsert the new bulb into bulb holder ;.XInsert bulb holder ; into the lamp and turn
it clockwise.XAlign housing cover : and turn it
clockwise until it engages.
Changing the rear bulbs
Opening and closing the side trim
panels
You must open the side trim panel in the trunk
and remove the first-aid kit before you can
change the bulbs in the tail lamps.
Replacing bulbs115Lights and windshield wipersZ

Left-hand side trim panel
Right-hand side trim panel
XTo open: turn rotary catch :90° in the
direction of the arrow and remove side trim
panel ;.XTo close: insert side trim panel ; and turn
release knob : 90° in the opposite
direction to the arrow.
Tail lamp
XSwitch off the lights.XOpen the trunk.XOpen the side trim panel ( Y page 115).XRemove the tail lamp connectorXSimultaneously press retaining lugs : in
the direction of the arrow and slightly pull
out the bulb holder with the bulbs.XRemove the connector for LED light
functions from the top of the bulb holder.XPull the bulb holder out with the bulbs.:Backup lamp;Brake lamp=Parking lamp/brake lampXPress the respective bulb :, ; or = back
and turn it counter-clockwise to remove it
from the bulb holder.XInsert the new bulb into the bulb holder and
turn it clockwise.XReinsert the connector for LED light
functions in the bulb holder.XInsert the bulb holder again and lock it in
place.XInsert the tail lamp connector.XClose the side trim panel ( Y page 115).
Windshield wipers
Switching the windshield wipers on/
off
GWARNING
Wiper blades are components that are subject
to wear and tear. Replace the wiper blades
twice a year, preferably in the spring and fall.
Otherwise the windshield will not be wiped
properly. As a result, you may not be able to
116Windshield wipersLights and windshield wipers

The emergency release is located in the trunk
behind the side trim on the right-hand side,
when viewed in the direction of travel.XOpen the trunk lid.XOpen the right-hand side trim panel
( Y page 306).XPull emergency release : in the direction
of the arrow.
The fuel filler flap is unlocked.XOpen the fuel filler flap.152RefuelingDriving and parking

Problems with fuel and the fuel tankProblemPossible causes/consequences and M SolutionsFuel is leaking from the
vehicle.GRisk of explosion or fire
The fuel line or the fuel tank is defective.
XTurn the SmartKey to position 0(Y page 137) in the ignition lock
immediately and remove it.XDo not restart the engine under any circumstances.XConsult a qualified specialist workshop.The fuel filler flap
cannot be opened.The fuel filler flap is not unlocked.
or
The SmartKey battery is discharged.XUnlock the vehicle using the mechanical key ( Y page 73).XOpen the trunk lid.XManually unlock the fuel filler flap using the emergency release
( Y page 151).The fuel filler flap is unlocked, but the opening mechanism is
jammed.XConsult a qualified specialist workshop.Parking
Important safety notes
GWARNING
Do not park this vehicle in areas where
combustible materials can come into contact
with the hot exhaust system. Do not park the
vehicle on dry grassland or harvested grain
fields. Combustible materials, such as grass,
hay or leaves could be ignited by the hot
exhaust system and cause a vehicle fire.
Unintended vehicle movement can cause
serious personal injury or damage to the
vehicle or the vehicle drivetrain. To reduce
such risks, always do the following before
turning off the engine and leaving the vehicle:
R keep your right foot on the brake pedal.
R engage the parking brake.
R shift the automatic transmission to park
position P.
R
slowly release the brake pedal.
R when parked on an incline, always turn the
front wheels towards the road curb.
R turn the SmartKey in the ignition lock to
position 0 and remove the SmartKey from
the ignition lock, or press the KEYLESS-GO
Start/Stop button.
R take the SmartKey with you and lock the
vehicle when leaving.
Switching off the engine
Important safety notes
GWARNING
Do not turn off the engine before the vehicle
has come to a complete stop. With the engine
not running, there is no power assistance for
the brake and steering systems. In this case,
it is important to keep in mind that a
Parking153Driving and parkingZ