key MERCEDES-BENZ R-Class 2012 W251 User Guide

Children can be killed or seriously injured by
an inflating air bag. Note the following
important information when circumstances
require you to place a child in the front-
passenger seat:
R Your vehicle is equipped with air bag
technology designed to deactivate the
front-passenger front air bag in your vehicle
when the system senses the weight of a
typical 12-month-old child or less along
with the weight of a standard appropriate
child restraint on the front-passenger seat.
R A child in a rear-facing child restraint on the
front-passenger seat will be seriously
injured or even killed if the front-passenger
front air bag inflates in a collision which
could occur under some circumstances,
even with the air bag technology installed
in your vehicle. The only means to eliminate
this risk completely is never to place a child
in a rear-facing child restraint in the front-
passenger seat. We therefore strongly
recommend that you always place a child
in a rear-facing child restraint on the rear
seat.
R If you install a rear-facing child restraint on
the front-passenger seat, make sure the
42 indicator lamp is
illuminated, indicating that the front-
passenger front air bag is deactivated.
Should the 42 indicator lamp
not illuminate or go out while the restraint
is installed, please check installation.
Periodically check the 42
indicator lamp while driving to make sure
the 42 indicator lamp is
illuminated. If the 42 indicator
lamp goes out or remains out, do not
transport a child on the front-passenger
seat until the system has been repaired.
A child in a rear-facing child restraint on the
front-passenger seat will be seriously
injured or even killed if the front-passenger
front air bag inflates.R If you place a child in a forward-facing child
restraint on the front-passenger seat:
- move the seat as far back as possible
- use the proper child restraint
recommended for the age, size and
weight of the child
- secure child restraint with the vehicle's
seat belt according to the child seat
manufacturer's instructions
R For children larger than a typical 12-month-
old child, the front-passenger front air bag
can be activated or deactivated.
If the driver's air bag deploys, this does not
mean that the front-passenger front air bag
also has to deploy.
The OCS may have detected that the seat:
R was empty or occupied by a person with a
weight of up to or less than that of a typical
12-month-old child seated in a standard
child restraint
R was occupied by a small individual, such as
a young teenager or a small adult
R was occupied by a child in a child restraint
system, whose weight is greater than that
of a typical 12-month-old child.
These are examples of when the OCS
deactivates the front-passenger front air bag.
Deactivation takes place although the
collision fulfills the criteria for deploying the
driver's air bag.
If the SmartKey has been removed from the
ignition lock or is in position 0, indicator lamp
42 : does not light up.
46Occupant safetySafety

GWARNING
If the red + SRS warning lamp in the
instrument cluster and the 42
indicator lamp light up simultaneously, the
OCS is malfunctioning. The front passenger
front air bag will be deactivated in this case.
Have the system checked by qualified
technicians as soon as possible. Contact an
authorized Mercedes-Benz Center.
Only have the seat repaired or replaced at an
authorized Mercedes-Benz Center.
In order to ensure proper operation of the air
bag system and OCS:
R Do not place more than 4.4 lb (2 kg) into the
parcel net on the rear of the front
passenger seat. Otherwise, the OCS may
not be able to properly approximate the
occupant weight category.
R Do not place objects under and/or around
the front passenger seat.
R Do not hang anything from or attach any
items to the seats.
R do not store any objects, such as books,
between the front passenger seat and the
center console or the front-passenger door.
R Do not move the front passenger seat
backwards against rigid objects.
R Sit with the seat belt properly fastened in a
position that is as upright as possible with
your back against the seat backrest.
R When seated, a passenger should not
position him/herself in such a way as to
cause the passenger's weight to be lifted
from the seat cushion as this may result in
the OCS being unable to correctly
approximate the passenger's weight
category.
R Read and observe all warnings in this
chapter.
System self-test
The 42 indicator lamp
illuminates when you:
R turn the SmartKey to position 1 or 2 in the
ignition lock
R press the KEYLESS-GO Start/Stop button
once or twice
If an adult occupant is properly sitting on the
passenger seat and the OCS classifies the
occupant as an adult, the 42
indicator lamp illuminates and goes out again
after approximately 6 seconds.
If the seat is not occupied and the OCS
classifies the front passenger seat as being
unoccupied, the 42 indicator
lamp will illuminate and not go out.
GWARNING
If the 4 2 indicator lamp does
not illuminate, the system is not functioning.
You must contact an authorized Mercedes-
Benz Center before seating any child on the
front passenger seat.
For more information, see "Problems with the
Occupant Classification System"
( Y page 48).
GWARNING
Never place anything between seat cushion
and child seat (e.g. a pillow), since it reduces
the effectiveness of the OCS. The underside
and rear side child restraint system must be
placed entirely on the seat cushion and the
backrest of the front-passenger seat
backrest.
If necessary, adjust the tilt of the passenger
seat backrest.
An incorrectly mounted child seat could cause
injuries to the child in case of an accident,
instead of increasing protection for the child.
Follow the manufacturer's instructions for
installation of child restraint systems.
Occupant safety47SafetyZ

be replaced and their anchoring points must
also be checked.
Only use seat belts which have been approved
by Mercedes-Benz.
Do not make any modifications to the seat
belts. This can lead to unintended activation
of the ETDs or to their failure to activate when
necessary.
Do not bleach or dye seat belts as this may
severely weaken them. In a crash they may
not be able to provide adequate protection.
Have all work carried out only by qualified
technicians. Contact an authorized
Mercedes-Benz Center.
Correct use of the seat beltsGWARNING
USE SEAT BELTS PROPERLY
R Seat belts can only work when used
properly. Never wear seat belts in any other
way than as described in this section, as
that could result in serious injuries in the
event of an accident.
R Each occupant should wear their seat belt
at all times, because seat belts help reduce
the likelihood of and potential severity of
injuries in accidents, including rollovers.
The integrated restraint system includes
SRS (driver front air bag, front-passenger
front air bag, side impact air bags, window
curtain air bags for the side windows),
Emergency Tensioning Devices, seat belt
force limiters, and front seat knee bolsters.
The system is designed to enhance the
protection offered to properly belted
occupants in certain frontal (front air bags
and ETDs) and side (side impact air bags,
window curtain air bags, and ETDs) impacts
which exceed preset deployment
thresholds and in certain rollovers (window
curtain air bags and ETDs).
R Never wear the shoulder belt under your
arm, across your neck or off your shoulder.
In a frontal crash, your body would move
too far forward. That would increase the
chance of head and neck injuries. The seat
belt would also apply too much force to the
ribs or abdomen, which could severely
injure internal organs such as your liver or
spleen.
Adjust the seat belt so that the shoulder
section is located as close as possible to
the middle of the shoulder. It should not
touch the neck. Never pass the shoulder
portion of the seat belt under your arm. For
this purpose, you can adjust the height of
the seat belt outlet.
R Position the lap belt as low as possible on
your hips and not across the abdomen. If
the lap belt is positioned across your
abdomen, it could cause serious injuries in
a crash.
R Never wear seat belts over rigid or
breakable objects in or on your clothing,
such as eyeglasses, pens, keys etc., as
these might cause injuries.
R Make sure the seat belt is always routed
snugly. Take special care of this when
wearing loose clothing.
R Never use a seat belt for more than one
person at a time. Do not fasten a seat belt
around a person and another person or
other objects at the same time.
R Seat belts should not be worn twisted. In a
crash, you would not have the full width of
the seat belt to distribute impact forces.
The twisted seat belt against your body
could cause injuries.
R Pregnant women should also always use a
lap-shoulder belt. The lap belt portion
should be positioned as low as possible on
the hips to avoid any possible pressure on
the abdomen.
R Place the seat backrest in a position that is
as upright as possible.
R Check your seat belt during travel to make
sure it is properly positioned.
R Never place your feet on the instrument
panel, dashboard, or on the seat. Always52Occupant safetySafety

For more information about releasing the seat
belt with release button ?, see "Releasing
seat belts" ( Y page 54).
Seat belt adjustment
The seat-belt adjustment function adjusts the
driver's and front-passenger seat belt to the
upper body of the occupants.
The belt strap is tightened slightly when:
R you engage the belt tongue in the belt
buckle and you then turn the SmartKey to
position 2 in the ignition lock.
R the SmartKey is in position 2 in the ignition
lock and you then engage the belt tongue
in the buckle.
The seat-belt adjustment will apply a
retraction force if any slack is detected
between the occupant and the seat belt. Do
not hold on to the seat belt tightly while it is
adjusting. You can switch the seat-belt
adjustment on and off in the on-board
computer ( Y page 209).
The seat-belt adjustment is an integral part of
the PRE-SAFE ®
convenience function. More
information about PRE-SAFE ®
can be found
in the "PRE-SAFE ®
(preventative occupant
protection)" section ( Y page 49).
Belt height adjustment
You can adjust the seat belt height on the
driver's seat and the front-passenger seat.
Adjust the height so that the upper part of the
seat belt is routed across the center of your
shoulder.
XTo raise: slide the belt sash guide upwards.
The belt sash guide engages in various
positions.XTo lower: press and hold belt sash guide
release :.XSlide the belt sash guide downwards.XRelease belt sash guide release : and
make sure that the belt sash guide has
engaged.
Releasing seat belts
XPress release button ?(Y page 53) and
guide belt tongue ; back towards belt
sash guide :.
!
Make sure that the seat belt is fully rolled
up. Otherwise, the seat belt or belt tongue
will be trapped in the door or in the seat
mechanism. This could damage the door,
the door trim panel and the seat belt.
Damaged seat belts can no longer fulfill
their protective function and must be
replaced. Consult an authorized Mercedes-
Benz Center.
Belt warning for the driver and front
passenger
Regardless of whether the driver and front
passenger have fastened their seat belts
already, the 7 seat belt warning lamp
lights up for 6 seconds after every engine
start. It then goes out if the driver and the
front passenger have fastened their seat
belts.
If the driver's seat belt is not fastened after
the engine is started, an additional warning
tone will sound. The warning tone goes out
after approximately six seconds or once the
driver's seat belt is fastened.
54Occupant safetySafety

GWARNING
When leaving the vehicle, always remove the
SmartKey from the ignition lock. Always take
the SmartKey with you and lock the vehicle.
Do not leave children unattended in the
vehicle, even if they are secured in a child
restraint system, 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. The children
could:
R injure themselves on parts of the vehicle
R be seriously or fatally injured through
excessive exposure to extreme heat or cold
R injure themselves or cause an accident with
vehicle equipment that can be operated
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
Do not carry heavy or hard objects in the
passenger compartment or trunk unless they
are firmly secured in place.
Unsecured or improperly positioned cargo
increases a child's risk of injury in the event
of
R strong braking maneuvers
R sudden changes of direction
R an accident
Special seat belt retractor
All seat belts except the driver's seat belt are
equipped with a special seat belt retractor.
When activated, the special seat belt
retractor ensures the seat belt will not
slacken once the child restraint system has
been secured.
Installing a child restraint system:XAlways comply with the manufacturer's
installation instructions.XPull the seat belt smoothly from the inertia
reel.XEngage the seat belt tongue in the belt
buckle.
Activating the special seat belt retractor:
XPull the seat belt out fully and let the inertia
reel retract it again.
While the seat belt is retracting, you should
hear a ratcheting sound. The special seat
belt retractor is enabled.XPush down on the child restraint system to
take up any slack.
Removing a child restraint system/
deactivating the special seat belt retractor:
XAlways comply with the manufacturer's
installation instructions.XPress the seat belt release button and
guide the belt tongue to the belt outlet.
The special seat belt retractor is
deactivated.GWARNING
Never release the seat belt buckle while the
vehicle is in motion, since the special seat belt
retractor will be deactivated.
LATCH-type (ISOFIX) child seat anchors
in the rear
GWARNING
Children that are too large for a child restraint
must travel in seats using normal seat belts.
Position shoulder belt across the chest and
shoulder, not face or neck.
In order to attain the correct seating position
for children weighing over 41 lb (18 kg), it may
be necessary to use a booster seat until they
reach a height where a normal lap/shoulder
58Children in the vehicleSafety

Child-proof locks
Important safety notesGWARNING
When leaving the vehicle, always remove the
SmartKey from the ignition lock. Always take
the SmartKey with you and lock the vehicle.
Do not leave children unattended in the
vehicle, even if they are secured in a child
restraint system, 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. The children
could:
R injure themselves on parts of the vehicle
R be seriously or fatally injured through
excessive exposure to extreme heat or cold
R injure themselves or cause an accident with
vehicle equipment that can be operated
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.
Child-proof locks for the rear doors
GWARNING
Children could open a rear door from inside
the vehicle. This could result in serious
injuries or an accident. Therefore, when
children ride in the rear always secure the rear
doors with the child-proof locks.
You secure each door individually with the
child-proof locks on the rear doors. A door
secured with a child-proof lock cannot be
opened from inside the vehicle. When the
vehicle is unlocked, the door can be opened
from the outside.XTo activate: press the child-proof lock
lever down in the direction of arrow ;.XMake sure that the child-proof locks are
working properly.XTo deactivate: press the child-proof lock
lever up in the direction of arrow :.
Override feature for the rear side
windows
GWARNING
When children ride on the vehicle's rear seats,
activate the override switch. Otherwise, the
children could be injured, e.g. by trapping
themselves in the rear side window.
XTo activate/deactivate: press switch :.
Switch : is pushed in or extended. If the
switch has engaged, operation of the rear
side windows is deactivated. Operation is
then only possible using the switches in the
driver's door.Children in the vehicle63SafetyZ

Panic alarmX To activate: press ! button : for at
least one second.
An alarm sounds and the exterior lighting
flashes.XTo deactivate: press ! button :
again.
or
XInsert the SmartKey into the ignition lock.
or
XPress the KEYLESS-GO Start/Stop button.
The KEYLESS-GO key must be in the
vehicle.
i USA only:
This device complies with Part 15 of the
FCC Rules. Operation is subject to the
following two conditions:
1. This device may not cause interference,
and
2. this device must accept any interference
received, including interference that may
cause undesired operation.
Any unauthorized modification to this
device could void the user's authority to
operate the equipment.
The product label with FCC ID and IC
certification number can be found in the
battery case of the SmartKey.
i Canada only:
This device complies with RSS-Gen of
Industry Canada. Operation is subject to
the following two conditions:
1. This device may not cause harmful
interference, and
2. this device must accept any interference
received, including interference that may
cause undesired operation.
Any unauthorized modification to this
device could void the user's authority to
operate the equipment.
The product label with FCC ID and IC
certification number can be found in the
battery case of the SmartKey.
Driving safety systems
Driving safety systems overview
In this section, you will find information about
the following driving safety systems:
R ABS ( Anti-lock Braking System)
R BAS ( Brake Assist System)
R ESP ®
(E lectronic Stability Program)
R EBD ( Electronic Brake force Distribution)
R Distance warning function (vehicles with
DISTRONIC)
Important safety notes
GWARNING
The following factors increase the risk of
accidents:
R Excessive speed, especially in turns
R Wet and slippery road surfaces
R Following another vehicle too closely
The driving safety systems described in this
section cannot reduce these risks or prevent
the natural laws of physics from acting on the
vehicle. They cannot increase braking or
steering efficiency beyond that afforded by
the condition of the vehicle brakes and tires
or the traction afforded.
Only a safe, attentive, and skillful driver can
prevent accidents.
The capabilities of a vehicle equipped with the
driving safety systems described in this
64Driving safety systemsSafety

Trailers with a high center of gravity may tip
over before the system recognizes swaying of
the trailer.
Trailer stabilization does not work if ESP ®
is
deactivated or disengaged because of a
malfunction.
EBD (electronic brake force
distribution)
i Observe the "Important safety notes"
section ( Y page 64).
EBD monitors and controls the brake
pressure on the rear wheels to improve
driving stability while braking.
GWARNING
If EBD has malfunctioned, the braking system
remains available with full brake boosting
effect. However, the rear wheels can still lock,
e.g. under full braking. This could cause you
to lose control of your vehicle and cause an
accident. You should therefore adapt your
driving style to the different handling
characteristics.
XObserve the notes on warning and indicator
lamps ( Y page 240) as well as display
messages ( Y page 216).
Distance warning function (vehicles
with DISTRONIC)
This function provides a warning from a speed
of approximately 20 mph(30 km/h), if:
R for a period of several seconds, the
distance to the vehicle in front is too short
for the speed at which you are traveling.
The · distance warning lamp in the
instrument cluster will light up.
R you are rapidly approaching the vehicle in
front. An intermittent warning tone will
then sound and the · distance warning
lamp will light up in the instrument cluster.
You must apply the brakes yourself in order
to maintain the appropriate distance to the
vehicle in front and prevent a collision.GWARNING
If the distance warning lamp · in the
instrument cluster comes on while driving
and/or an intermittent warning sounds,
immediate attention on the part of the driver
is required. As required by the traffic
situation, apply the brakes and navigate
around a possible obstacle. However, do not
drive by relying on the distance warning
function, as this will result in an emergency
braking application. This will not always
enable you to avoid a collision, especially
when traveling on varying road surface
conditions and with varying driver reaction.
Complex driving situations are not always
fully recognized by the distance warning
function. This could result in wrong or missing
distance warnings.
XTo activate/deactivate: activate or
deactivate the distance warning function in
the on-board computer ( Y page 210).
After activation, the Ä symbol is
displayed in the lower multifunction
display.
Theft deterrent locking systems
Immobilizer
The immobilizer prevents your vehicle from
being started without the correct SmartKey.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. The
engine can be started by anyone with a valid
SmartKey that is left inside the vehicle.
XTo activate with the SmartKey: remove
the SmartKey from the ignition lock.XTo activate with KEYLESS-GO: switch the
ignition off and open the driver's door.XTo deactivate: switch on the ignition.68Theft deterrent locking systemsSafety

iThe immobilizer is always deactivated
when you start the engine.
In the event that the engine cannot be
started when the starter battery is fully
charged, the immobilizer may be faulty.
Contact an authorized Mercedes-Benz
Center or call 1-800-FOR-MERCedes (in
USA) or 1-800-387-0100 (in Canada).
ATA (Anti-Theft Alarm system)
A visual and audible alarm is triggered if the
alarm system is armed and you open:
R a door
R the vehicle with the mechanical key
R the tailgate
R the hood
The alarm is not switched off, even if you
close the open door that has triggered it, for
example.
i If the alarm stays on for more than 30
seconds, the emergency call system
mbrace (USA only) or TELE AID (Canada
only) initiates a call to the Customer
Assistance Center automatically. The
emergency call system initiates the call
provided that:
R you have subscribed to the mbrace/
TELE AID service.
R the mbrace/TELE AID service has been
activated properly.
R the required mobile phone, power supply
and GPS are available.
XTo arm: lock the vehicle with the SmartKey
or KEYLESS-GO.
Indicator lamp : flashes. The alarm
system is armed after approximately 10
seconds.XTo deactivate: unlock the vehicle with the
SmartKey or KEYLESS-GO.XTo stop the alarm using the SmartKey:
insert the SmartKey into the ignition lock.
The alarm is switched off.
or
XPress the % or & button on the
SmartKey.
The alarm is switched off.XTo stop the alarm using KEYLESS-GO:
grasp the outside door handle. The
SmartKey must be outside the vehicle.
The alarm is switched off.
or
XPress the Start/Stop button on the
dashboard. The SmartKey must be inside
the vehicle.
The alarm is switched off.Theft deterrent locking systems69SafetyZ

Useful information ..............................72
SmartKey ............................................. 72
Doors .................................................... 79
Cargo compartment ............................81
Side windows ...................................... 86
Sliding sunroof .................................... 8971Opening/closing