
dehumidification function remains on. Air-
recirculation mode remains deactivated.
or
XPress the ^ button.
or
XPress the à button.
or
XTurn the temperature control clockwise or
counter-clockwise.
or
XPress the K or I button.
Defrosting the windows
Windows fogged up on the inside
XActivate the "cooling with air
dehumidification" function Á.XActivate automatic mode Ã.XIf the windows continue to fog up, activate
the defrosting function ( Y page 142).
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 P/\ 21
or O /c 21
air distribution button.
i You should only select this setting until
the windshield is clear again.
Rear window heating
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 heating 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 heating may switch off.XTurn the SmartKey to position 2 in the
ignition lock.XPress the ª button.
The indicator lamp in the ª button lights
up or goes out.
Problems with the rear window heating
If the indicator lamp in the ª rear window
heating button flashes, the on-board voltage
is too low or the roof is open. The rear window
heating 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 heating 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 the air-recirculation mode is
the same for all control panels.
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.
21 Canada only.Operating climate control systems143Climate controlBA 251 USA, CA Edition A 2011; 1; 3, en-USd2sboikeVersion: 3.0.3.52010-04-16T14:31:55+02:00 - Seite 143Z

XTurn the SmartKey to position 2 in the
ignition lock.XTo activate: press the d button.
The indicator lamp in the d button lights
up.
i Air-recirculation mode is activated
automatically at high outside
temperatures. When air-recirculation mode
is activated automatically, the indicator
lamp in the d button is not lit.
Outside air is added after about 30
minutes.
XTo deactivate: press the d button.
The indicator lamp in the d button goes
out.
i Air-recirculation mode switches off
automatically:
R after approximately five minutes if
outside temperatures are under 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 †)
i The air-recirculation mode does not
switch off automatically if outside
temperatures exceed 79 ‡ (26 †). After
about 30 minutes, outside air will be
added. 22
Switching the residual heat on/off
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 switch on: press the Á button.
The indicator lamp in the Á button lights
up.XTo switch off: press the Á button.
The indicator lamp in the Á 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 guidelines
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
vehicle interior that are not in the immediate
area of unprotected skin.
22 Vehicles with multi-zone automatic climate control.144Setting the air ventsClimate control
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SmartKey positions
SmartKeygTo remove the SmartKey1Power supply for some consumers, such
as the windshield wipers2Ignition (power supply for all consumers)
and drive position3To start the engine
As soon as the ignition is switched on, all the
indicator lamps in the instrument cluster light
up. The indicator lamps of the low-beam
headlamps, high-beam headlamps or the turn
signal lamps only light up if the low-beam
headlamps, high-beam headlamps or turn
signal lamps are switched on. If an indicator
lamp does not light up when the ignition is
switched on, check it and replace it if
necessary. 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 236).
XRemove the SmartKey when the engine is
switched off.
The battery may otherwise discharge.
If you cannot turn the SmartKey in the ignition
lock, the vehicle battery may not be charged
sufficiently.
XCheck the vehicle battery and charge if
necessary ( Y page 310).
or
XJump-start the vehicle ( Y page 311).
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
Vehicles with KEYLESS-GO are equipped with
a SmartKey with an integrated KEYLESS-GO
function and a detachable Start/Stop button.
The Start/Stop button must be inserted in the
ignition lock and the SmartKey must be in the
vehicle.
Pressing the Start/Stop button several times
in succession corresponds to the different
key 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 in 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 and the
electrical equipment can be operated while
the SmartKey is in the vehicle.
:Start/Stop button;Ignition lockXInsert Start/Stop button : into ignition
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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.XTurn the SmartKey back to position 0 in the ignition lock before
the next attempt to start with the SmartKey.XBefore the next starting attempt with KEYLESS-GO: shut all open
vehicle doors so that the signals from the SmartKey may be
better received.
or
XPull the Start/Stop button out of the ignition.XUse the SmartKey to start the engine, (Y page 150) as external
radio signals cause KEYLESS-GO to malfunction. 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.The engine does not
start. You cannot hear
the starter motor.The on-board voltage is too low because the starter battery is too
weak or discharged.XJump-start the vehicle ( Y page 311).
If the engine does not start despite attempts to jump-start it:
XConsult a qualified specialist workshop.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.154DrivingDriving and parking
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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 up the vehicle
If you leave the vehicle parked up for longer
than four weeks, the battery may be damaged
by exhaustive discharge.
XDisconnect the battery or connect it to 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 up 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.Driving tips
General driving tips
Important safety instructions
GWarning!
Please do not forget that your primary
responsibility is to drive the vehicle. A driver’s
attention to the road must always be his/her
primary focus when driving. For your safety
and the safety of others, we recommend that
you pull over to a safe location and stop
before placing or taking a telephone call.
If you choose to use the telephone 25
while
driving, please use the hands-free device and
only use the telephone when road, weather
and traffic conditions permit. Some
jurisdictions prohibit the driver from using a
mobile telephone while driving a vehicle.
Only operate the COMAND 25
(Cockpit
Management and Data System) if road,
weather and traffic conditions permit.
Otherwise, you may not be able to observe
traffic conditions and could endanger yourself
and others.
Bear in mind that at a speed of just 30 mph
(approximately 50 km/h), your vehicle is
covering a distance of 44 feet (approximately
14 m) every second.
Drive sensibly – save fuel
To save fuel, observe the following notes:
XKeep tires at the recommended inflation
pressures.XRemove unnecessary cargo.XRemove the roof carrier when not in use.XMaintain a low engine speed until the
engine is warm.XAvoid frequent acceleration and
deceleration.XHave all maintenance work performed at
the service intervals specified in the25 Observe all legal requirements.168Driving tipsDriving and parking
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Display messagesPossible causes/consequences and M Solutions?The engine fan is faulty.XAt coolant temperatures under 248 ‡(120 †), drive to the next
qualified specialist workshop.XAvoid subjecting the engine to heavy loads, e.g. driving in
mountainous terrain, and stop-start driving.#The battery is not being charged.
Possible causes are:
R a faulty alternator
R a torn poly-V-belt
R a malfunction in the electronicsXPull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions.XOpen the hood.XCheck whether the poly-V-belt is torn.
If the poly-V-belt is torn:
! Do not continue driving. The engine could otherwise overheat.
XConsult a qualified specialist workshop.
If the poly-V-belt is OK:
XVisit a qualified specialist workshop.#
Battery/
Alternator Stop
VehicleThe battery is faulty.XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions. Do not continue driving
under any circumstances.XEngage the parking brake.XConsult a qualified specialist workshop.4
Check engine oil
level at next
refuelingThe oil level is too low.XCheck the oil level ( Y page 279).XIf necessary, add the engine oil ( Y page 280).XHave the engine checked for leaks if engine oil has to be added
more often than usual.
Information on approved engine oils can be obtained from any qualified specialist workshop
or on the Internet at http://www.mbusa.com (USA only).
! The oil level is too low. Avoid long journeys with too little engine oil. There is a risk of
engine damage.
The display messages and the corresponding symbol that indicate that the oil level is too
low must not be ignored.
226Display messagesOn-board computer and displays
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Display messagesPossible causes/consequences and M Solutionsh
Tire Pressure
Check TiresGRisk of accident
The tire pressure in one or more tires has dropped significantly.
XStop the vehicle without making any sudden steering or braking
maneuvers. Pay attention to the traffic conditions as you do so.XIf necessary, change the wheel ( Y page 336).XCheck the tire pressure. If necessary, correct the tire pressure
( Y page 327).h
Please correct the
tire pressuresThe tire pressure is insufficient in at least one of the tires or the
tire pressure difference between the wheels is too great.XCheck the tire pressures at the next opportunity. If necessary,
correct the tire pressure ( Y page 327).
Vehicle
Display messagesPossible causes/consequences and M SolutionsShift to P or N
to start engineYou have attempted to start the engine with the transmission in
position R or D. XShift the transmission to position P or N.Auxiliary Battery
MalfunctionThe auxiliary battery for the automatic transmission is no longer
being charged.XVisit a qualified specialist workshop.Depress brake
to shift out of PYou have attempted to move the transmission selector lever to
position D, R or N without depressing the brake pedal.XDepress the brake pedal.Door Open
Vehicle Not In ParkThe driver's door is open and the transmission is in position R, N
or D.XShift the transmission to position P.XEngage the parking brake.Drive to workshop
without shifting
gearsYou cannot change the transmission position due to a malfunction.
If transmission position D is selected:XDrive to a qualified specialist workshop without shifting the
transmission from position D.
If transmission position R, N or P is selected:
XNotify a qualified specialist workshop or breakdown service.Display messages233On-board computer and displaysBA 251 USA, CA Edition A 2011; 1; 3, en-USd2sboikeVersion: 3.0.3.52010-04-16T14:31:55+02:00 - Seite 233Z

Safety systemsProblemPossible causes/consequences and M Solutions!
The yellow ABS warning
lamp is lit while the
engine is running. GRisk of accident
ABS (Anti-lock Brake System) is deactivated due to a malfunction.
Therefore, BAS (Brake Assist), ESP ®
(Electronic Stability Program),
EBD (Electronic Brake-force Distribution) and PRE-SAFE ®
are also
deactivated.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
XObserve the additional display messages in the multifunction
display.XDrive on carefully.XVisit a qualified specialist workshop.
If the ABS control unit is faulty, there is also a possibility that other
systems, such as the navigation system or the automatic
transmission, will not be available.
!
The yellow ABS warning
lamp is lit while the
engine is running.GRisk of accident
The on-board voltage is too low. ABS has been deactivated due to
undervoltage.
Therefore, ESP ®
, BAS and PRE-SAFE ®
are also deactivated.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
XSwitch off consumers that are not required, e.g. the rear window
defroster or interior lighting.
ABS will be available again as soon as the vehicle's on-board
electrical system voltage increases.
If the warning lamp is still on:
XHave the battery and alternator checked at a qualified specialist
workshop.!
The yellow ABS warning
lamp is lit while the
engine is running.Self diagnosis is not yet complete.XCarefully drive a suitable distance making slight steering
movements at a speed above 12 mph (20 km/h).Warning and indicator lamps in the instrument cluster239On-board computer and displaysBA 251 USA, CA Edition A 2011; 1; 3, en-USd2sboikeVersion: 3.0.3.52010-04-16T14:31:55+02:00 - Seite 239Z