Engine MERCEDES-BENZ R-Class 2012 W251 Owner's Guide

XTurn the light switch to $ or à .
or
XIf the rear fog lamp is switched on: press
the light switch in to the stop.
Low-beam headlamps
XTo 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.XTo switch off the low-beam
headlamps: turn the light switch to $.
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 $ 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
activated, the T indicator lamp on the
light switch and the L indicator lamp in
the instrument cluster light up.
If the light switch is set to $ or à , you
cannot activate the high-beam headlamps.
Turn the light switch to L when driving at
night. You can switch on the high-beam
headlamps in this position.
When the engine is running and the vehicle is
stationary: if you move the selector lever from
a driving position to N or P, the low-beam
headlamps go out after three minutes.
When the engine is running and the vehicle is
stationary: if you turn the light switch
to T , the parking lamps and the low-beam
headlamps are switched on.
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: activate the daytime running lamps
function in the on-board computer
( Y page 206).XTurn the light switch to $ or à .
With the engine running: the low-beam
headlamps are switched on. The T
indicator lamp on the light switch and the
L indicator lamp in the instrument
cluster light up.
It is only possible to activate the high-beam
headlamps if the brightness of the ambient
light is at a low level.
However, the high-beam flasher can always
be used.
If the engine is running and you turn the light
switch to T or L , the manual settings
take precedence over the daytime running
lamps.
Automatic headlamp mode
XTo switch on automatic headlamp
mode: turn the light switch to Ã.
SmartKey in position 1 in the ignition lock:
the parking lamps are switched on or off
automatically depending on the brightness
of the ambient light.
With the engine running: depending on the
brightness of the ambient light, the daytime
running lamps 10
or the low-beam
headlamps are switched on or off
automatically.
When the low-beam headlamps are
switched on, the L indicator lamp in the
instrument cluster lights up.GWARNING
If the light switch is set to Ã, the low-beam
headlamps will not come on automatically if
it is foggy. This could endanger you and
10 Only if daytime running lamps have been activated via the on-board computer.Exterior lighting115Lights and windshield wipersZ

others. Therefore, turn the light switch to
L in fog.
The automatic headlamp feature is only an
aid. The driver is responsible for the vehicle's
lighting at all times.GWARNING
In low ambient lighting or foggy conditions,
only switch from position à to L with
the vehicle at a standstill in a safe location.
Switching from à to L will briefly
switch off the headlamps. Doing so while
driving in low ambient lighting conditions may
result in an accident.
Front fog lamps and rear fog lamp
Front fog lamps
Only vehicles with front fog lamps have the
"fog lamps" function.
GWARNING
If you suspect that driving conditions will be
foggy, turn the light switch to L before you
start your journey. Otherwise, your vehicle
may not be visible and you could endanger
yourself and others.
GWARNING
In low ambient lighting or foggy conditions,
only switch from position à to L with
the vehicle at a standstill in a safe location.
Switching from à to L will briefly
switch off the headlamps. Doing so while
driving in low ambient lighting conditions may
result in an accident.
XTo switch on the front fog lamps: turn
the SmartKey in the ignition lock to position
2 or start the engine.XTurn the light switch to L or T . If the
light switch is set to Ã, you cannot
switch on the fog lamps.XPull the light switch out to the first detent.
The green N indicator lamp on the light
switch lights up.XTo switch off the front fog lamps: press
the light switch in as far as it will go.
The green N indicator lamp on the light
switch goes out.
Rear fog lamp
XTo switch on (vehicles with front fog
lamps): turn the SmartKey in the ignition
lock to position 2 or start the engine.XTurn the light switch to L or T . When
the light switch is set to Ã, you cannot
switch on the rear fog lamp.XTurn the light switch to L. When the
light switch is set to T, you cannot
switch on the rear fog lamp.XPull the light switch out to the second stop.
The yellow R indicator lamp on the light
switch lights up.XTo switch off the rear fog lamp: press the
light switch in as far as it will go.
The yellow R indicator lamp on the light
switch goes out.XTo switch on (vehicles without front fog
lamps): turn the SmartKey in the ignition
lock to position 2 or start the engine.XTurn the light switch to L. When the
light switch is set to Ã, you cannot
switch on the rear fog lamp.XTurn the light switch to L. When the
light switch is set to c, you cannot
switch on the rear fog lamp.XPull the light switch out to the stop.
The yellow R indicator lamp on the light
switch lights up.XPull the light switch out to the stop.
The yellow R indicator lamp in the
instrument cluster lights up.116Exterior lightingLights and windshield wipers

XTo switch off the rear fog lamp: press the
light switch in as far as it will go.
The yellow R indicator lamp on the light
switch goes out.XTo switch off the rear fog lamp: press the
light switch in as far as it will go.
The yellow R indicator lamp in the
instrument cluster goes out.
Headlamp cleaning system
The headlamps are cleaned automatically if
the "Wipe with washer fluid" function is
operated ten times while the lights are on and
the engine is running (Y page 124). When you
switch off the ignition, the automatic
headlamp cleaning system is reset and
counting is resumed from 0.
Combination switch
Turn signals
:High-beam headlamps;Right turn signal=High-beam flasher?Left turn signalXTo indicate briefly: press the combination
switch briefly to the pressure point in the
direction of arrow ; or ?.
The corresponding turn signal flashes three
times.XTo indicate: press the combination switch
beyond the pressure point in the direction
of arrow ; or ?.High-beam headlampsXTo switch on the high-beam headlamps:
turn the SmartKey in the ignition lock to
position 2 or start the engine.XTurn the light switch to L.XPress the combination switch beyond the
pressure point in the direction of
arrow :.
The K indicator lamp in the instrument
cluster lights up.XTo switch off the high-beam
headlamps: move the combination switch
back to its normal position.
The K indicator lamp in the instrument
cluster goes out.
High-beam flasher
XTo switch on: turn the SmartKey in the
ignition lock to position 1 or 2 or start the
engine.XPull the combination switch in the direction
of arrow =.
Hazard warning lamps
The hazard warning lamps automatically
switch on if:
R an air bag is deployed.
R the vehicle is slowed down severely from a
speed of over 45 mph (70 km/h) and comes
to a halt.
Exterior lighting117Lights and windshield wipersZ

Rear overhead control panel (second row of seats)
:Switches the reading lamp on/off
Rear overhead control panel (third row of seats)
:p Switches the left-hand reading lamp
on/off;p Switches the right-hand 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 control
XTo 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 208).
Manual interior lighting controlXTo switch the front interior lighting on/
off: press the c button.XTo switch the rear interior lighting on/
off: press the v 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
key.
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
observed, the lights must be switched on
before starting the engine.
Replacing bulbs119Lights and windshield wipersZ

XFor safety reasons, you should remove the
SmartKey from the ignition lock.
or
XSwitch off the engine using the Start/Stop
button and open the driver's door.XRemove the cause of the obstruction.XSwitch the windshield wipers back on.
The windshield wipers are inoperative
The windshield wiper drive is malfunctioning.
XSelect another wiper speed on the
combination switch.XHave the windshield wipers checked at a
qualified specialist workshop.
The spray nozzles are misaligned
The windshield washer fluid from the spray
nozzles no longer hits the center of the
windshield. The spray nozzles are misaligned.
XHave the spray nozzles adjusted at a
qualified specialist workshop.Windshield wipers127Lights and windshield wipersZ

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).
Overview of climate control systems
Important safety notes
GWARNING
Severe conditions (e.g. strong air pollution)
may require replacement of the filter before
its scheduled replacement interval. A clogged
filter will reduce the air volume to the interior
and the windows could fog up, impairing
visibility and endangering you and others.
Have a blocked filter replaced at a Mercedes-
Benz Center as soon as possible.
GWARNING
Follow the recommended settings for heating
and cooling given on the following pages.
Otherwise, the windows could fog up,
impairing visibility and endangering you and
others.
The automatic climate control 13
adjusts the
temperature and the humidity of the vehicle
interior and filters undesired substances from
the air.
The automatic climate control 13
is only
operational when the engine is running. 14
Optimum operation is only achieved if you
drive with the side windows and sliding
sunroof/panorama roof with power tilt/
sliding panel closed.
i Ventilate the vehicle for a brief period
during warm weather, e.g. using the
convenience opening feature ( Y page 87).
This will speed up the cooling process and
the desired vehicle interior temperature
will be reached more quickly.
i The integrated filter can filter out most
particles of dust and completely filters out
pollen. A clogged filter reduces the amount
of air supplied to the vehicle interior. For
this reason, you should always observe the
interval for replacing the filter, which is
specified in the Service Booklet. As it
depends on environmental conditions, e.g.
heavy air pollution, the interval may be
shorter than stated in the Service Booklet.13 Canada only.
14 Automatic climate control: the residual heat function can only be activated/deactivated when the ignition
is switched off.130Overview of climate control systemsClimate control

Switching the front climate control on/
off using the front control panelXTurn the SmartKey to position 2 in the
ignition lock.XTo switch on: press the à button.
The indicator lamp in the à button lights
up. Airflow and air distribution are set to
automatic mode.
or
XPress the ^ button.
The indicator lamp in the ^ button goes
out. The previously selected settings come
into effect again.XTo switch off: press the ^ button.
The indicator lamp in the ^ button lights
up.
Switching the rear-compartment
climate control on/off using the front
control panel
2-zone automatic climate control
XTurn the SmartKey to position 2 in the
ignition lock.XTo switch on/off: press the ± button.
The indicator lamp in the ± button lights
up or goes out.
3-zone automatic climate control
USA only:
XTurn the SmartKey to position 2 in the
ignition lock.XTo switch on/off: press the ± button.
The indicator lamp in the ± button lights
up or goes out.
Canada only:
XTurn the SmartKey to position 2 in the
ignition lock.XTo switch on: press the Y button.
ON and MODE are shown in the automatic
climate control display behind the Y
symbol. The MODE display goes out after
three seconds. The display switches back
to the standard display.XTo switch off: press the Y button.
MODE is shown in the display behind the
Y symbol.XPress button ^.
OFF is shown in the display behind the
Y symbol.
Switching the rear-compartment
climate control on/off using the rear
control panel
3-zone automatic climate control
XTurn the SmartKey to position 2 in the
ignition lock.XSwitch on automatic climate control using
the front control panel.XTo switch on: press the à button.
The indicator lamp in the à button lights
up.XTo switch off: press the ^ button.
The indicator lamp in the ^ button lights
up.
Activating/deactivating the cooling
with air dehumidification function
Important information
The cooling with air dehumidification function
is only available when the engine is running.
The air inside the vehicle is cooled and
dehumidified according to the temperature
selected.
GWARNING
If you switch off the cooling function, the
vehicle will not be cooled when weather
conditions are warm. The windows can fog up
more quickly. Window fogging may impair
visibility and endanger you and others.
Condensation may drip from the underside of
the vehicle when it is in cooling mode. This is
normal and not a sign that there is a
malfunction.
Operating the climate control system135Climate controlZ

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
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 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 switch off: press the d button.
The indicator lamp in the d 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 †)
i The air-recirculation mode is not
deactivated automatically at outside
temperatures above 79 ‡ (26 †). After
approximately 30 minutes, outside air is
added. 21
Activating/deactivating the residual
heat function
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 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.21 Vehicles with automatic climate control140Operating the climate control systemClimate control

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 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.
R If possible, drive in drive program E for the
first 1000 miles (1500 km).
After 1000 miles (1500 km), you can increase
the engine speed gradually and bring the
vehicle up to full speed.
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.
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.
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.
144DrivingDriving and parking

Where possible, avoid spinning the drive
wheels when pulling away on slippery
roads. You could otherwise damage the
drive train.
SmartKey positions
SmartKey
gTo remove the SmartKey1Power supply for some consumers, such
as the windshield wipers2Ignition (power supply for all consumers)
and drive position3To start the engine
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.
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 and the
electrical equipment can be operated while
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 :.
Driving145Driving and parkingZ