2012 MERCEDES-BENZ C-Class COUPE key battery

Illustration: light switch with the c symbol for
the automatic headlamp mode/daytime running
lamps
1 WLeft-hand standing lamps2XRight-hand standing lamps3TParking lamps, license plate and
instrument cluster lighting4 cAutomatic headlamp mode/daytime
running lamps5 LLow-beam/high-beam headlampsBRRear fog lampCNFront fog lamps 4
The turn signals, high-beam headlamps and
the high-beam flasher are operated using the
combination switch ( Y page 103).
! Switch off the parking lamps and standing
lamps when you leave the vehicle. This
prevents the battery from discharging.
The exterior lighting (except the parking/
standing lamps) switches off automatically if
you:
R remove the SmartKey from the ignition lock
R open the driver's door with the SmartKey
in position 0
If you hear a warning tone when you leave the
vehicle, the lights may still be switched on.
XTurn the light switch to c or à .Low-beam headlampsXTo switch on the low-beam headlamps:
turn the SmartKey in the ignition lock to
position 2 or start the engine.XTurn the light switch to L.
The L indicator lamp in the instrument
cluster lights up.
Daytime running lamps
Daytime running lamps in Canada
The daytime running lamps function is
required by law in Canada. It cannot therefore
be deactivated.
XTurn the light switch to c or à .
With the engine running: depending on the
ambient light, the daytime running lamps or
the low-beam headlamps are switched on.
When the low-beam headlamps are
switched on, the L indicator lamp in the
instrument cluster lights up.
When the engine is running and the vehicle is
stationary: if you move the selector lever from
a drive position to P (vehicles with automatic
transmission) or if the parking brake is
applied, the low-beam headlamps go out after
three minutes.
When the engine is running, the vehicle is
stationary and in high ambient light
brightness: if you turn the light switch
to T , the daytime running lamps and the
parking lamps are switched on.
If the engine is running and you turn the light
switch to L, the manual settings take
precedence over the daytime running lamps.
Daytime running lamps in the USA
In the USA, the daytime running lamps are
deactivated upon delivery from the factory.
XTo activate the daytime running lamps
(vehicles with a luxury multifunction
steering wheel): you can activate the4
Only vehicles with front fog lamps have the fog lamps function.Exterior lighting101Lights and windshield wipers

XDrive with the headlamps switched on.
The level of moisture diminishes,
depending on the length of the journey and
the weather conditions (humidity and
temperature).
If the level of moisture does not diminish:
XHave the headlamps checked at a qualified
specialist workshop.
Interior lighting
Overview of interior lighting
:u Switches the rear interior lighting
on/off;| Switches the automatic interior
lighting control on/off=p Switches the right-hand front
reading lamp on/off?c Switches the front interior lighting
on/offAp Switches the left-hand front reading
lamp on/off
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 SmartKey is in position
2 in the ignition lock.
Automatic interior lighting controlXTo switch on/off: press the | button.
When the automatic interior lighting
control is activated, the button is flush with
the overhead control panel.
The interior lighting automatically switches
on if you:
R unlock the vehicle
R open a door
R remove the SmartKey from the ignition lock
The interior light is activated for a short while
when the SmartKey is removed from the
ignition lock. You can activate this delayed
switch-off using the on-board computer
( Y page 196).
Manual interior lighting control
XTo switch the interior lighting on/off:
press the c button.XTo switch the reading lamps on/off:
press the p button.
Crash-responsive emergency lighting
The interior lighting is activated automatically
if the vehicle is involved in an accident.
XTo switch off the crash-responsive
emergency lighting: press the hazard
warning lamp button.
or
XLock and then unlock the vehicle using the
SmartKey.
Replacing 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
106Replacing bulbsLights and windshield wipers

iYou should only select this setting until
the windshield is clear again.
Windows fogged up on the outsideXSwitch on the windshield wipers.XPress the _ button repeatedly until the
O or P symbol appears in the
display.
i You should only select this setting until
the windshield is clear again.
Rear window defroster
Activating/deactivating
GWARNING
Any accumulation of snow and ice should be
removed from the rear window before driving.
Visibility could otherwise be impaired,
endangering you and others.
The rear window defroster has a high current
draw. You should therefore switch it off as
soon as the window is clear as it only switches
off automatically after several minutes.
If the battery voltage is too low, the rear
window defroster may switch off.
XTurn the SmartKey to position 2 in the
ignition lock.XPress the ¤ button.
The indicator lamp in the ¤ button lights
up or goes out.
Problems with the rear window
defroster
The rear window defroster has deactivated
itself prematurely or cannot be activated.
XSwitch off any consumers that are not
required, e.g. reading lamps or interior
lighting.
When the battery is sufficiently charged,
the rear window defroster is activated
again automatically.Activating/deactivating air-
recirculation mode
You can deactivate the flow of fresh air if
unpleasant odors are entering the vehicle
from outside. The air already inside the
vehicle will then be recirculated.GWARNING
Fogged windows impair visibility,
endangering you and others. If the windows
begin to fog on the inside, switching off the
air recirculation mode immediately should
clear interior window fogging. If interior
window fogging persists, make sure the air
conditioning is activated, or press the ¬
button.
XTurn the SmartKey to position 2 in the
ignition lock.XTo activate: press the g button.
The indicator lamp in the g button lights
up.
i In the event of high pollution levels or at
high outside temperatures, air-
recirculation mode is automatically
activated. When air-recirculation mode is
activated automatically, the indicator lamp
in the g button is not lit.
Outside air is added after about 30
minutes.
XTo switch off: press the g button.
The indicator lamp in the g button goes
out.
Setting the air vents
Important safety notes
GWARNING
When operating the climate control, the air
that enters the passenger compartment
through the air vents can be very hot or very
cold (depending on the set temperature). This
could cause burns or frostbite to unprotected
skin in the immediate area of the air vents.
120Setting the air ventsClimate control

Problems with the engineProblemPossible causes/consequences and M SolutionsThe engine does not
start. The starter motor
can be heard.R There is a malfunction in the engine electronics.
R There is a malfunction in the fuel supply.XBefore attempting to start the engine again, turn the SmartKey
in the ignition back to position 0 or press the Start/Stop button
repeatedly until all indicator lamps in the instrument cluster go
out.XTry to start the engine again ( Y page 126). Avoid excessively
long and frequent attempts to start the engine as these will drain
the battery.
If the engine does not start after several attempts:
XConsult a qualified specialist workshop, e.g. an authorized
Mercedes-Benz Center.The engine does not
start. You cannot hear
the starter motor.The on-board voltage is too low because the battery is too weak
or discharged.XJump-start the vehicle ( Y page 287).
If the engine does not start despite attempts to jump-start it:
XConsult a qualified specialist workshop, e.g. an authorized
Mercedes-Benz Center.The starter motor was exposed to a thermal load that was too high.XAllow the starter motor to cool down for approximately two
minutes.XTry to start the engine again.
If the engine still does not start:
XConsult a qualified specialist workshop, e.g. an authorized
Mercedes-Benz Center.Driving129Driving and parkingZ

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 125) 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 71).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
considerably higher degree of effort is
necessary to brake and steer the vehicle.
Vehicles with automatic transmission
XApply the parking brake firmly.XShift the transmission to position P.140ParkingDriving and parking

Using the SmartKeyXTurn the SmartKey to position 0 in the
ignition lock and remove it.
The immobilizer is activated.
i The SmartKey can only be removed if the
transmission is in position P.
Using KEYLESS-GO
XPress the Start/Stop button (Y page 125).
The engine stops and all the indicator
lamps in the instrument cluster go out.
i When the driver's door is closed, this
corresponds to SmartKey position 1. When
the driver's door is open, it corresponds to
SmartKey position 0 or "SmartKey
removed".
If you attempt to switch off the engine while
the selector lever is in a position other than
P , a message appears in the multifunction
display and you hear a tone.
Parking brake
GWARNING
Engaging the parking brake while the vehicle
is in motion can cause the rear wheels to lock
up. You could lose control of the vehicle and
cause an accident. In addition, the vehicle's
brake lights do not light up when the parking
brake is engaged.
GWARNING
When leaving the vehicle, always remove the
SmartKey from the starter switch, take it with
you, and lock the vehicle. Do not leave
children unattended in the vehicle, or with
access to an unlocked vehicle. Children could
release the parking brake and/or shift the
automatic transmission out of park position
P , either of which could result in an accident
and/or serious personal injury.
XTo apply: depress parking brake ; firmly.
When the engine is running, the $ (USA
only) or J (Canada only) indicator lamp
lights up in the instrument cluster.XTo release: depress the brake pedal and
keep it depressed.XPull release handle :.
When the ignition is switched on or the
engine is running, the $ (USA only) or
J (Canada only) indicator lamp goes out
in the instrument cluster.
Parking the vehicle for a long period
If you leave the vehicle parked for longer than
four weeks, the battery may be damaged by
exhaustive discharge.
XConnect a trickle charger.
i You can obtain information about trickle
chargers from a qualified specialist
workshop, e.g. an authorized Mercedes-
Benz Center.
If you leave the vehicle parked for longer than
six weeks, the vehicle may suffer damage as
a result of lack of use.
XVisit a qualified specialist workshop and
seek advice.Parking141Driving and parkingZ

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 KeyThe 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 72).Â
Don't Forget Your
KeyThe display message is shown for a maximum of 60 seconds and
is only a reminder.
You have opened the driver's door with the engine switched off.
The KEYLESS-GO key is not in the ignition lock.XRemember to take the KEYLESS-GO key with you when you
leave 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.XApply 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 SmartKey in the ignition lock.226Display messagesOn-board computer and displays

even if the SmartKey is removed from the
ignition lock 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 on these
parts.GWARNING
Never touch the heating element or sides of
the lighter; they are extremely hot. Hold the
knob only.
Make sure any children traveling with you do
not injure themselves or start a fire with the
hot cigarette lighter.
XTurn the SmartKey to position 2 in the
ignition lock.XTo open: slide cover : forwards until it
engages.XPress in cigarette lighter ;.
Cigarette lighter ; will pop out
automatically when the heating element is
red-hot.XTo close: press cover : briefly at the
front.
The cover moves back.12 V sockets
Points to observe before use
The sockets can be used for accessories, e.g.
lamps or mobile phone chargers with a
maximum current draw of 180 W (15 A).
If you use the sockets for long periods when
the engine is switched off, the battery may
discharge.
XTurn the SmartKey to position 1 in the
ignition lock.
i An emergency cut-out ensures that the
on-board voltage does not drop too low. If
the on-board voltage is too low, the power
to the sockets is automatically cut. This
ensures that there is sufficient power to
start the engine.
Socket in the rear-compartment center
console
XPull cover ; out by its top edge.XLift up the cover of socket :.
115 V socket
GWARNING
The 115V AC socket operates at high voltage.
Use the 115V AC socket in the vehicle with
the same caution and prudence that you
exercise when using power outlets at home.
Keep any fluids away from the 115V AC
socket. Do not clean the socket with fluids or
tapered objects. Keep the 115V AC socket
Features249Stowing and featuresZ