air condition MERCEDES-BENZ R-Class 2012 W251 Owner's Manual

1, 2, 3 ...
115 V socket ...................................... 268
12 V socket see Sockets
4ETS (Electronic Traction System) .... 66
A
ABS (Anti-lock Braking System) Display message ............................ 214
Function/notes ................................ 65
Important safety notes ....................65
Warning lamp ................................. 240
Activating/deactivating cooling
with air dehumidification ................. 135
Active service system PLUS see ASSYST PLUS service interval
display
Adaptive Damping System (ADS) ..... 181
Additives (engine oil) ........................ 358
Adjusting the armrest (2nd row of
seats) .................................................. 102
ADS (Adaptive Damping System) ..... 181
Air bags Display message ............................ 220
Front air bag (driver, front
passenger) ....................................... 42
Important safety notes ....................40
Safety guidelines ............................. 39
Side impact air bag ..........................42
Window curtain air bag ....................43
Air-conditioning system
see Climate control
Air filter (display message) .............. 228
AIRMATIC (display message) ............ 229
AIRMATIC package ............................ 180
Air pressure see Tire pressure
Air vents
Important safety notes ..................141
Rear ............................................... 142
Setting ........................................... 141
Setting the center air vents ...........141
Setting the side air vents ...............141
Alarm system
see ATA (Anti-Theft Alarm system)
Anti-lock Braking System
see ABS (Anti-lock Braking System)
Anti-Theft Alarm system
see ATA (Anti-Theft Alarm system)
Anti-theft system
ATA (Anti-Theft Alarm system) .........69
Ashtray ............................................... 265
ASSYST PLUS see ASSYST PLUS service interval
display
ATA (Anti-Theft Alarm system)
Activating/deactivating ...................69
Function ........................................... 69
Switching off the alarm ....................69
Audio menu (on-board computer) .... 203
Audio system see separate operating instructions
Authorized Mercedes-Benz Center
see Qualified specialist workshop
AUTO lights
Display message ............................ 225
see Lights
Automatic headlamp mode .............. 115
Automatic transmission Automatic drive program ...............154
Changing gear ............................... 152
DIRECT SELECT lever .....................150
Display message ............................ 234
Driving tips .................................... 153
Emergency running mode ..............156
Kickdown ....................................... 153
Problem (malfunction) ...................156
Program selector button ................153
Pulling away ................................... 147
Shift ranges ................................... 154
Starting the engine ........................146
Steering wheel paddle shifters ......153
Trailer towing ................................. 153
Transmission position display ........151
Transmission positions ..................152
Automatic transmission
emergency mode ............................... 1564Index

SeatFolding down the 2nd row of
seats .............................................. 254
Important safety notes ....................97
Resetting the 2nd row of seats ......256
Resetting the 3rd row of seats ....... 256
Seat belts
Adjusting the driver's and front-
passenger seat belt .........................54
Adjusting the height ......................... 54
Belt force limiters ............................ 55
Cleaning ......................................... 293
Correct usage .................................. 52
Emergency Tensioning Devices ........ 55
Fastening ......................................... 53
Important safety guidelines .............51
Releasing ......................................... 54
Safety guidelines ............................. 39
Special seat belt retractor ...............58
Switching belt adjustment on/off
(on-board computer) ......................209
Warning lamp ................................. 238
Warning lamp (function) ................... 54
Seats
Adjusting (electrically) .....................98
Adjusting (second and third rows) . 101
Adjusting the 4-way lumbar
support .......................................... 105
Adjusting the head restraint ............99
Cleaning the cover .........................293
Correct driver's seat position ........... 96
Folding down the 3rd row of seats . 255
Folding the rear bench seat
forwards/back ............................... 253
Multicontour seat .......................... 105
Seat heating problem ....................106
Seat ventilation problem ................107
Storing settings (memory
function) ........................................ 112
Switching seat heating on/off .......106
Switching the seat ventilation on/
off .................................................. 106
Securing hooks .................................. 258
Sensors (cleaning instructions) ....... 291
Service see ASSYST PLUS service interval
display Service interval display
Displaying service messages .........287
Hiding service messages ...............287
Notes ............................................. 287
Service messages ..........................287
Service products
Brake fluid ..................................... 359
Capacities ...................................... 355
Coolant (engine) ............................ 359
DEF special additives .....................357
Engine oil ....................................... 358
Fuel ................................................ 356
Important safety notes ..................354
Refrigerant (air-conditioning
system) .......................................... 359
Washer fluid ................................... 360
Settings
Factory (on-board computer) .........205
On-board computer .......................205
Setting the air distribution ............... 138
Setting the airflow ............................ 138
Side impact air bag ............................. 42
Side marker lamp (display
message) ............................................ 224
Side marker lamps (changing
bulbs) ................................................. 123
Side windows Convenience closing feature ............88
Convenience opening feature ..........87
Hinged side windows .......................87
Important safety information ...........86
Opening/closing .............................. 86
Problem (malfunction) .....................89
Resetting ......................................... 89
Sliding sunroof
Important safety notes ....................89
Opening/closing .............................. 90
Problem (malfunction) .....................92
Resetting ......................................... 90
see Panorama roof with power
tilt/sliding panel
SmartKey
Changing the battery .......................76
Changing the programming .............75
Checking the battery .......................76
Convenience closing feature ............88
Convenience opening feature ..........87
Display message ............................ 236Index15

Rhode Island and Vermont Emission
Control Systems Warranty
R State Warranty Enforcement Laws (Lemon
Laws)
Information for customers in
California
Under California law you may be entitled to a
replacement of your vehicle or a refund of the
purchase price or lease price, if after a
reasonable number of repair attempts
Mercedes-Benz USA, LLC and/or its
authorized repair or service facilities fail to fix
one or more substantial defects or
malfunctions in the vehicle that are covered
by its express warranty. During the period of
18 months from original delivery of the
vehicle or the accumulation of 18 000 miles
(approximately 29 000 km) on the odometer
of the vehicle, whichever occurs first, a
reasonable number of repair attempts is
presumed for a retail buyer or lessee if one or
more of the following occurs:
(1)the same substantial defect or
malfunction results in a condition that is
likely to cause death or serious bodily
injury if the vehicle is driven, that defect
or malfunction has been subject to repair
two or more times, and you have directly
notified Mercedes-Benz USA, LLC in
writing of the need for its repair.(2)the same substantial defect or
malfunction of a less serious nature than
category (1) has been subject to repair
four or more times and you have directly
notified Mercedes-Benz in writing of the
need for its repair.(3)the vehicle is out of service by reason of
repair of the same or different substantial
defects or malfunctions for a cumulative
total of more than 30 calendar days.
Please send your written notice to:
Mercedes-Benz USA, LLC
Customer Assistance Center
One Mercedes Drive
Montvale, NJ 07645-0350
Maintenance
The Service and Warranty Booklet describes
all the necessary maintenance work which
should be done at regular intervals.
Always have the Service and Warranty
Booklet with you when you bring the vehicle
to an authorized Mercedes-Benz Center. The
service advisor will record every service for
you in the Service and Warranty Booklet.
Roadside Assistance
The Mercedes-Benz Roadside Assistance
Program offers technical help in the event of
a breakdown. Calls to the toll-free Roadside
Assistance Hotline are answered by our
agents 24 hours a day, 365 days a year.
1-800-FOR-MERCedes(1-800-367-6372)
(USA)
1-800-387-0100 (Canada)
For additional information, refer to the
Mercedes-Benz Roadside Assistance
Program brochure (USA) or the "Roadside
Assistance" section in the Service and
Warranty booklet (Canada). You will find both
in your vehicle literature portfolio.
In accordance with standard program
guidelines, Roadside Assistance provides
vehicle service up to a reasonable distance
from the next paved road. We will make every
effort to assist in a breakdown situation.
However, the accessibility of your vehicle will
be determined by our authorized Mercedes-
Benz Service technician or the tow service
provider on a case-by-case basis.
Additional charges may be applicable for a
breakdown location determined not to be a
reasonably accessible roadside location as
determined by our authorized technician and
tow service provider.
22Introduction

GWARNING
If the 42 indicator lamp does not illuminate or remains out with the weight of a
typical 12-month-old child in a standard child restraint or less, or is unoccupied, on the front-
passenger seat, do not transport a child on the front-passenger seat until the system has been
repaired.
PRE-SAFE ®
(preventative occupant
protection)GWARNING
The PRE-SAFE ®
system reduces the impact of
an accident on vehicle occupants, as long as
their seat belts have been fastened correctly.
Although your vehicle is equipped with a PRE-
SAFE ®
system, the possibility of injury in the
event of an accident cannot be ruled out. You
should therefore always drive carefully and
adapt your driving style to the prevailing road,
weather and traffic conditions.
PRE-SAFE ®
takes preemptive measures to
protect occupants in certain hazardous
situations.
PRE-SAFE ®
intervenes:
R in emergency braking situations when BAS
intervenes
R in critical driving situations, e.g. when
physical limits are exceed and the vehicle
understeers or oversteers severely
PRE-SAFE ®
takes the following measures
depending on the hazardous situation
detected:
R the front seat belts are pre-tensioned.
R on vehicles with memory function for the
front-passenger seat: the front-passenger
seat is adjusted if it is in an unfavorable
position.
R if the vehicle skids, the side windows are
closed so that only a small gap remains.
R on vehicles with a sliding sunroof: if the
vehicle skids, the sliding sunroof closes so
that only a small gap remains.
If the hazardous situation passes without
resulting in an accident, PRE-SAFE ®
slackens
the belt pretensioning. All settings made by
PRE-SAFE ®
can then be reversed.
If the seat belts are not released:XMove the backrest or seat back slightly, but
only when the vehicle is stationary.
The belt pretensioning is reduced and the
locking mechanism is released.GWARNING
Make sure that nobody can become trapped
as you adjust the seat.
! Make sure that there are no objects in the
footwell or behind the seats when resetting
the seats. There is a risk that the seats
and/or the objects could be damaged.
More information about seat-belt
adjustment, a convenience function
integrated into PRE-SAFE ®
, can be found in
the "Seat-belt adjustment" section
( Y page 54).
NECK-PRO head restraints/NECK-
PRO luxury head restraints
NECK-PRO head restraints/NECK-PRO luxury
head restraints increase protection of the
driver's and front-passenger's head and
neck. In the event of a rear collision of a
certain severity, the NECK-PRO head
restraints/NECK-PRO luxury head restraints
on the driver's and front-passenger seats are
moved forwards and upwards. This provides
better head support.
GWARNING
Do not attach any objects (e.g. a coat hanger)
to the NECK-PRO head restraints/NECK-PRO
luxury head restraints. Otherwise, the NECK-
Occupant safety49SafetyZ

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

iThe cooling with air dehumidification
function uses refrigerant R134a. This
coolant does not contain
chlorofluorocarbons, and therefore does
not damage the ozone layer.
Activating/deactivating
! If the cooling with air dehumidification
does not switch on, it is possible that the
climate control system has lost coolant.
Have the cooling with air dehumidification
checked at a qualified specialist workshop.
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. The cooling with air dehumidification
function has a delayed switch-off feature.
Problems with the cooling with air
dehumidification function
If the indicator lamp in the Á button does
not go out when the function is activated, the
cooling with air dehumidification function is
deactivated due to a malfunction. You can no
longer switch on the cooling with air
dehumidification function.
XConsult a qualified specialist workshop.
Setting climate control to automatic
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.
In automatic mode, the set temperature is
maintained automatically at a constant level.
The system automatically regulates the
temperature of the dispensed air, the airflow
and the air distribution.
Automatic mode will achieve optimal
operation if cooling with air dehumidification
is also activated. If desired, cooling with air
dehumidification can be deactivated.
Controlling the front climate control
using the front control panelXTurn the SmartKey to position 2 in the
ignition lock.XSet the desired temperature.XTo activate: press the à button.
The indicator lamp in the à button lights
up. Automatic air distribution and airflow
are activated.XTo deactivate: press the K or I
button.
The indicator lamp in the à button goes
out. Automatic airflow is deactivated and
the airflow is controlled according to the
level set. Automatic air distribution
remains activated.
or
XPress the Z, M , ¯ , \ , P ,
c or O button.
The indicator lamp in the à button goes
out. Automatic air distribution is
deactivated. Air distribution is controlled
according to the position set. Automatic
airflow remains activated.
Controlling the rear-compartment
climate control automatically using the
rear control panel
XTurn the SmartKey to position 2 in the
ignition lock.XSwitch on automatic climate control using
the front control panel.XSet the desired temperature.XTo activate: press the à button.
The indicator lamp in the à button lights
up. Automatic air distribution and airflow
are activated.136Operating the climate control systemClimate control

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

Exhaust checkGWARNING
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.
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.
Certain engine systems are designed to keep
the level of poisonous components in exhaust
fumes within legal limits.
These systems only work at peak efficiency
when they are maintained exactly in
accordance with the manufacturer's
specifications. For this reason, all work on the
engine must be carried out only by qualified
and authorized Mercedes-Benz technicians.
The engine settings must not be changed in
any circumstances. Furthermore, all specific
service work must be carried out at regular
intervals and in accordance with the
Mercedes-Benz service requirements. Details
can be found in the Service Booklet.
Engine oil
! Vehicles with a diesel particle filter:
If the vehicle is mostly driven for short
distances, it is possible that malfunctions
may occur during the automatic cleaning of
the diesel particle filter. This can lead to
engine damage. Therefore, if you frequently
drive short distances, make sure to drive
on highways or inter-urban roads for 20
minutes at least every 310 miles (500 km).
Brakes
Important safety notesGWARNING
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
Make sure that you do not endanger other
road users when you apply the brakes.
Downhill gradients
! On long and steep gradients, you must
reduce the load on the brakes by shifting
early to a lower gear. This allows you to take
advantage of the engine braking effect and
helps avoid overheating and excessive
wear of the brakes.
When you take advantage of the engine
braking effect, a drive wheel may not turn
for some time, e.g. on a slippery road
surface. This could cause damage to the
drive train. This type of damage is not
covered by the Mercedes-Benz warranty.
Heavy and light loads
GWARNING
Depressing the brake pedal constantly results
in excessive and premature wear to the brake
pads.
It may also cause the brakes to overheat,
seriously impairing their effectiveness. It may
then not be possible to stop the vehicle in
sufficient time to avoid an accident.
If the brakes have been subjected to a heavy
load, do not stop the vehicle immediately, but
drive on for a short while. This allows the
airflow to cool the brakes more quickly.
166Driving tipsDriving and parking

Wet roadsGWARNING
After driving in heavy rain for some time
without applying the brakes or through water
deep enough to wet brake components, the
first braking action may be somewhat
reduced. You have to depress the brake pedal
more firmly. Maintain a safe distance from
vehicles in front.
After driving on a wet road or having the
vehicle washed, brake firmly while paying
attention to the traffic conditions. This will
warm up the brake discs, thereby drying them
more quickly and protecting them against
corrosion.
Limited braking performance on salt
treated roads
GWARNING
The layer of salt on the brake discs and the
brake pads/linings may cause a delay in the
braking effect, resulting in a significantly
longer braking distance, which could lead to
an accident.
To avoid this danger, you should:
R occasionally brake carefully, without
putting other road users at risk, when you
are driving on salted roads. This helps to
remove any salt that may have started to
build up on the brake discs and the brake
pads/linings.
R maintain a greater distance to the vehicle
ahead and drive with particular care.
R carefully apply the brakes at the end of a
trip and immediately after commencing a
new trip, so that salt residues are removed
from the brake discs.
Servicing the brakes
! If the brake warning lamp lights up in the
instrument cluster and you hear a warning
tone even though the parking brake has
been released, the brake fluid level may be
too low. Observe additional warning
messages in the multifunction display.
The brake fluid level may be too low due to
brake pad wear or leaking brake lines.
Have the brake system checked
immediately. Have this work carried out at
an authorized Mercedes-Benz Center.
All checks and maintenance work on the
brake system must be carried out at a
qualified specialist workshop. This work
should be carried out at an authorized
Mercedes-Benz Center.
Have the brake pads and brake fluid installed
or replaced at a qualified specialist workshop,
e.g. an authorized Mercedes-Benz Center.GWARNING
If other than recommended brake pads are
installed, or other than recommended brake
fluid is used, the braking properties of the
vehicle can be degraded to an extent that safe
braking is substantially impaired. This could
result in an accident.
! A function or performance test should
only be carried out on a 2-axle
dynamometer. If you are planning to have
the vehicle tested on such a dynamometer,
contact an authorized Mercedes-Benz
Center to obtain further information first.
Otherwise, you could damage the drive
train or the brake system.
! As the ESP ®
system operates
automatically, the engine and the ignition
must be switched off (SmartKey in position
0 or 1 in the ignition lock or Start/Stop
button in position 0 or 1) while the parking
brake is being tested on a brake
dynamometer (maximum 10 seconds).
Braking maneuvers triggered automatically
by ESP ®
may seriously damage the brake
system.
If your brake system is subject only to
moderate loads, you should test the
functionality of your brakes at regular
intervals by pressing firmly on the brake pedal
Driving tips167Driving and parkingZ