engine MERCEDES-BENZ C-Class SEDAN 2012 W204 Service Manual

orXPress the K or I button.
MAX COOL maximum cooling
The MAX COOL function is only available in
vehicles for the USA.
MAX COOL is only operational when the
engine is running.
When you activate MAX COOL, climate
control switches to the following functions:
R maximum cooling
R maximum airflow
R air-recirculation mode on
XTo activate: press the Ù button.
The indicator lamp in the button lights up.XTo deactivate: press the Ù button
again.
The indicator lamp goes out. The previously
selected settings come into effect again.
Defrosting the windows
Windows fogged up on the inside
XActivate the cooling with air
dehumidification function ¿.XActivate automatic mode Ã.XIf the windows continue to fog up, activate
the defrosting function ( Y page 129).
i
You should only select this setting until
the windshield is clear again.
Windows fogged up on the outside
XSwitch 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/deactivatingGWARNING
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.
The operation of air-recirculation mode is the
same for all control panels.
GWARNING
Fogged windows impair visibility,
endangering you and others. If the windows
130Operating the climate control systemClimate control

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 14
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.
i Air-recirculation mode deactivates
automatically:
R after approximately five minutes if
outside temperatures are less than about
41 ‡ (5 †)
R after approximately five minutes if
cooling with air dehumidification is
deactivated
R after approximately 30 minutes if outside
temperatures are over about
41 ‡ (5 †)
Activating/deactivating the residual
heat function
The residual heat function is only available in
vehicles for Canada with automatic climate
control.
It is possible to make use of the residual heat
of the engine to continue heating the
stationary vehicle for up to 30 minutes after
the engine has been switched off. The heating
time depends on the temperature that has
been set.
i The blower will run at a low speed
regardless of the airflow setting.
i If you activate the residual heat function
at high temperatures, only the ventilation
will be activated. The blower runs at
medium speed.XTurn the SmartKey to position 0 in the
ignition lock or remove it.XTo activate: press the Ì button.
The indicator lamp in the Ì button lights
up.XTo switch off: press the Ì button.
The indicator lamp in the Ì button goes
out.
i Residual heat is deactivated
automatically:
R after about 30 minutes
R when the ignition is switched on
R if the battery voltage drops
R if the coolant temperature is too low
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.
Always keep sufficient distance between
unprotected parts of the body and the air
vents. If necessary, use the air distribution
adjustment to direct the air to air vents in the
14 Automatic climate control only.Setting the air vents131Climate controlZ

Useful information
i This Operator's Manual describes all
models and all standard and optional
equipment of your vehicle available at the
time of publication of the Operator's
Manual. Country-specific differences are
possible. Please note that your vehicle may
not be equipped with all features
described. This also applies to safety-
related systems and functions.
i Please read the information on qualified
specialist workshops ( Y page 24).
Breaking-in notes
The first 1000 miles (1500 km)
The more you look after the engine when it is
new, the more satisfied you will be with its
performance in the future.
R Drive at varying vehicle speeds and engine
speeds for the first 1000 miles (1500 km)
for this reason.
R Avoid overstraining the vehicle during this
period, e.g. driving at full throttle.
R Change gear in good time, at the latest
when the tachometer needle is 2
/ 3 of the
way to the red area in the tachometer
display.
R If possible, drive in drive program E (in AMG
vehicles in drive program C) for the first
1000 miles (1500 km).
R Do not manually shift to a lower gear to
brake the vehicle.
R If possible, do not depress the accelerator
pedal past the point of resistance
(kickdown).
R Only select shift ranges 3, 2 or 1 when
driving slowly, e.g. in mountainous terrain.
After 1000 miles (1500 km), you can increase
the engine speed gradually and bring the
vehicle up to full speed.
Additional breaking-in notes for AMG
vehicles:
R do not drive faster than 85 mph
(140 km/h) in the first 1000 miles
(1500 km).
R only allow the engine to reach a maximum
engine speed of 4500 rpm briefly.
R change gear in good time.
i You should also observe these notes on
running in if the engine or parts of the drive
train on your vehicle have been replaced.
i Always observe the respective speed
restrictions.
AMG vehicles with rear axle locking
differential
Your vehicle is equipped with a self-locking
differential on the rear axle. For better
protection of the differential on the rear axle,
carry out an oil change after a breaking-in
phase of 2000 miles (3000 km). This oil
change extends the service life of the
differential. Have the oil change carried out
at a qualified specialist workshop. Mercedes-
Benz recommends that you use an authorized
Mercedes-Benz Center for this purpose.
Driving
Important safety notes
GWARNING
Make sure absolutely no objects are
obstructing the pedals' range of movement.
Keep the driver's footwell clear of all
obstacles. If there are any floormats or
carpets in the footwell, make sure the pedals
still have sufficient clearance.
During sudden driving or braking maneuvers
the objects could get caught between the
pedals. You could then no longer brake or
accelerate. This could lead to accidents and
injury.
136DrivingDriving and parking

GWARNING
On slippery road surfaces, never downshift in
order to obtain braking action. This could
result in drive wheel slip and reduced vehicle
control. Your vehicle's ABS will not prevent
this type of loss of control.
GWARNING
It is dangerous to shift the automatic
transmission out of parking position P or
neutral position N if the engine speed is
higher than idle speed. If your foot is not firmly
on the brake pedal, the vehicle could
accelerate quickly forward or in reverse. You
could lose control of the vehicle and hit
someone or something. Only shift into gear
when the engine is idling normally and when
your right foot is firmly on the brake pedal.
! Warm up the engine quickly. Do not use
the engine's full performance until it has
reached operating temperature.
Only shift the automatic transmission to
the desired drive position when the vehicle
is stationary.
Where possible, avoid spinning the drive
wheels when pulling away on slippery
roads. You could otherwise damage the
drive train.
! AMG vehicles: at low engine oil
temperatures (below 68 ‡ (+20 †), the
maximum engine speed is restricted in
order to protect the engine. To protect the
engine and maintain smooth engine
operation, avoid driving at full throttle when
the engine is cold.
SmartKey positions
SmartKeygTo remove the SmartKeyVehicles with automatic transmission:
shift the transmission to position P1Power supply for some consumers, such
as the windshield wipers2Ignition (power supply for all consumers)
and drive position3To start the engine
If the SmartKey is in position 0 in the ignition
lock for an extended period of time, it can no
longer be turned in the ignition lock. The
steering is then locked. To unlock, remove the
SmartKey and reinsert it into the ignition lock.
The steering is locked when you remove the
SmartKey from the ignition lock.
i The SmartKey can be turned in the
ignition lock even if it is not the correct
SmartKey for the vehicle. The ignition is not
switched on. The engine cannot be started.
KEYLESS-GO
General information
Vehicles with KEYLESS-GO are equipped with
a SmartKey featuring an integrated KEYLESS-
GO function and a detachable Start/Stop
button.
The Start/Stop button must be inserted into
the ignition lock and the SmartKey must be in
the vehicle.
Driving137Driving and parkingZ

Pressing the Start/Stop button several times
in succession corresponds to the different
SmartKey positions in the ignition lock. This
is only the case if you are not depressing the
brake pedal.
If you depress the brake pedal and press the
Start/Stop button, the engine starts
immediately.
The Start/Stop button can be removed from
the ignition lock. Then, you can insert the
SmartKey into the ignition lock.
i You do not have to remove the Start/Stop
button from the ignition lock when you
leave the vehicle. However, you should
always take the SmartKey with you when
leaving the vehicle. The vehicle can be
started with the Start/Stop button if the
SmartKey is in the vehicle.:Start/Stop button;Ignition lockXInsert Start/Stop button : into ignition
lock ;.
i
When you insert Start/Stop button :
into ignition lock ;, the system requires a
detection time of approximately two
seconds before you can use Start/Stop
button :.
Start/Stop button
=USA only?Canada onlyXPosition 0: if Start/Stop button : has not
yet been pressed, this corresponds to the
SmartKey being removed from the ignition.XPosition 1: press Start/Stop button :.
You can now activate the windshield
wipers, for example.
i If you then open the driver's door when in
this position, the power supply is
deactivated.
XPosition 2 (ignition): press Start/Stop
button : twice.
i
If you press Start/Stop button : once
when in this position and the driver's door
is open, the power supply is deactivated
again.
As soon as the ignition is switched on, all the
indicator lamps in the instrument cluster light
up. If an indicator lamp does not go out after
the engine is started or if it lights up while the
vehicle is in motion, see ( Y page 241).
Starting the engine
Important safety notes
GWARNING
Inhalation of exhaust gas is hazardous to your
health. All exhaust gas contains carbon
monoxide (CO), and inhaling it can cause
unconsciousness and possible death.
138DrivingDriving and parking

Do not run the engine in confined areas (such
as a garage) which are not properly ventilated.
If you think that exhaust gas fumes are
entering the vehicle while driving, have the
cause determined and corrected
immediately. If you must drive under these
conditions, drive only with at least one
window fully open at all times.
! Do not depress the accelerator pedal
when starting the engine.
i The catalytic converter preheats for up to
30 seconds after a cold start. The sound of
the engine may change during this time.
Automatic transmissionXShift the transmission to position P.
The transmission position display in the
multifunction display shows P.
i
You can also start the engine when the
transmission is in position N.
Starting procedure with the SmartKey
i To start the engine using the SmartKey
instead of KEYLESS-GO, pull the Start/
Stop button out of the ignition lock.
XTurn the SmartKey to position 3 in the
ignition lock (Y page 137) and release it as
soon as the engine is running.
Using KEYLESS-GO to start the engine
GWARNING
As long as the SmartKey is in your vehicle, the
vehicle can be started. Therefore, never leave
children unattended in the vehicle, as they
could otherwise accidentally start the engine.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Do
not leave children unattended in the vehicle,
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.
i The Start/Stop button can be used to
start the vehicle without inserting the
SmartKey into the ignition lock. The Start/
Stop button must be inserted into the
ignition lock and the SmartKey must be in
the vehicle.XDepress the brake pedal and keep it
depressed.XPress the Start/Stop button ( Y page 137)
once.
The engine starts.
Pulling away
Automatic transmission
GWARNING
It is dangerous to shift the automatic
transmission out of parking position P or
neutral position N if the engine speed is
higher than idle speed. If your foot is not firmly
on the brake pedal, the vehicle could
accelerate quickly forward or in reverse. You
could lose control of the vehicle and hit
someone or something. Only shift into gear
when the engine is idling normally and when
your right foot is firmly on the brake pedal.
i It is only possible to shift the transmission
from position P to the desired position if
you depress the brake pedal. Only then is
the selector lever lock released.
XDepress the brake pedal and keep it
depressed.XShift the transmission to position D or R.XRelease the parking brake ( Y page 154).XRelease the brake pedal.XCarefully depress the accelerator pedal.
!
If a warning tone sounds and the
Release Park. Brake message appears
in the multifunction display, the parking
brake is still applied. Release the parking
brake.
Driving139Driving and parkingZ

iThe vehicle locks centrally once you have
pulled away. The locking knobs in the doors
drop down.
You can open the doors from the inside at
any time.
You can also deactivate the automatic
locking feature ( Y page 208).
i Upshifts take place at higher engine
speeds after a cold start. This helps the
catalytic converter to reach its operating
temperature more quickly.
Hill start assist
Hill start assist helps you when pulling away
forwards or in reverse on an uphill gradient.
It holds the vehicle for a short time after you
have removed your foot from the brake pedal.
This gives you enough time to move your foot
from the brake pedal to the accelerator pedal
and depress it before the vehicle begins to
roll.
GWARNING
Never leave the vehicle when it is held by hill
start assist. After approximately one second,
hill start assist will no longer brake your
vehicle and it could roll away.
XTake your foot off the brake pedal.
i Once you have taken your foot off the
brake pedal, the vehicle is held for around
one second.
XPull away.
Hill start assist will not function if:
R you are pulling away on a level road or a
downhill gradient.
R the transmission is in position N.
R the parking brake is applied.
R ESP ®
is malfunctioning.
140DrivingDriving and parking

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 138). 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 301).
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.Driving141Driving and parkingZ

ProblemPossible causes/consequences and M SolutionsThe engine is not
running smoothly and
is misfiring.There is a malfunction in the engine electronics or a mechanical
component of the engine management system.XOnly depress the accelerator pedal slightly.XHave the cause rectified immediately at a qualified specialist
workshop, e.g. an authorized Mercedes-Benz Center.
Otherwise, non-combusted fuel may get into the catalytic
converter and damage it.The coolant
temperature gauge
shows a value above
248 ‡ (120 †).The coolant level is too low. The coolant is too hot and the engine
is no longer being cooled sufficiently.XStop as soon as possible and allow the engine and the coolant
to cool down.XCheck the coolant level ( Y page 280). Observe the warning
notes as you do so and add coolant if necessary.Automatic transmission
Important safety notes
GWARNING
It is dangerous to shift the automatic
transmission out of parking position P or
neutral position N if the engine speed is
higher than idle speed. If your foot is not firmly
on the brake pedal, the vehicle could
accelerate quickly forward or in reverse. You
could lose control of the vehicle and hit
someone or something. Only shift into gear
when the engine is idling normally and when
your right foot is firmly on the brake pedal.
GWARNING
Keep in mind that turning off the engine alone
only will shift the automatic transmission into
neutral position N automatically.
Always shift the automatic transmission into
park position P before turning off the engine.
Otherwise the vehicle could roll away which
could result in an accident and/or serious
personal injury.
Selector lever
Overview of transmission positions
Example: selector lever
PPark position with selector lever lockRReverse gearNNeutralDDrive142Automatic transmissionDriving and parking

ANeutral
Do not shift the transmission to N
while driving. The transmission
could otherwise be damaged.
No power is transmitted from the
engine to the drive wheels.
Releasing the brakes will allow you
to move the vehicle freely, e.g. to
push it or tow it.
If ESP ®
is deactivated or faulty:
only shift the transmission to
position N if the vehicle is in danger
of skidding, e.g. on icy roads.
! Rolling in neutral N can damage
the drive train.7Drive
The automatic transmission
changes gear automatically. All
forward gears are available.
Changing gear
The automatic transmission shifts to the
individual gears automatically when it is in
transmission position D. This automatic
gearshifting behavior is determined by:
R a shift range restriction, if selected
R the selected drive program ( Y page 144)
R the position of the accelerator pedal
R the road speed
Driving tips
AMG vehicles
When shifting down, the double-clutch
function is active regardless of the currently
selected drive program. The double-clutch
function reduces load change reactions and
is conducive to a sporty driving style. The
sound generated by the double-clutch
function depends on the drive program
selected.
Kickdown
Use kickdown for maximum acceleration.
XVehicles for USA (except AMG
vehicles): fully depress the accelerator
pedal.
The transmission shifts to a lower gear
depending on the engine speed.XVehicles for Canada and AMG vehicles:
depress the accelerator pedal beyond the
pressure point.
The transmission shifts to a lower gear
depending on the engine speed.
Working on the vehicle
GWARNING
When working on the vehicle, engage the
parking brake and shift the automatic
transmission into park position P. Otherwise
the vehicle could roll away which could result
in an accident and/or serious personal injury.
Program selector button
General information
The program selector button allows you to
choose between different driving
characteristics.
Example: program selector button
144Automatic transmissionDriving and parking