MERCEDES-BENZ R320 2008 W251 Manual PDF

70 Safety and Security
Occupant safety
In this section you will learn the most
important facts about the restraint
systems of the vehicle.
The restraint systems are

Seat belts (page 82)

Child restraints (page 92)

Lower Anchors and Tethers for
CH
ildren (LATCH) (page 91)
Additional protection provide

Supplemental Restraint System (SRS)
with

Air bags (page 72)

Air bag control unit (with crash
sensors)

Emergency Tensioning Device
(ETD) for seat belts (
page 85)

Active head restraints (page 86)Air bag system components with

Front passenger front air bag off
indicator lamp (
page 81)

Front passenger seat with Occupant
C
lassification System (OCS)
(
page 77)
Although independent systems, their
protective functions work in conjunction
with each other.The SRS system conducts a self-test when
the ignition is switched on and in regular
intervals while the engine is running. This
facilitates early detection of malfunctions.
The 1indicator lamp in the instrument
cluster (
page 26) comes on when the
ignition is switched on and goes out no
later than a few seconds after the engine
was started.
The SRS components are in operational
readiness if the 1indicator lamp is not
lit when the engine is running.
A malfunction in the system has been
detected if the 1indicator lamp:

fails to go out no later than approxi-
mately 4 seconds after the engine was
started

does not come on at all

comes on after the engine was started
or while driving
iFor information on infants and children
traveling with you in the vehicle and restraint
systems for infants and children, see “Children
in the vehicle” (
page 87).

71 Safety and Security
Occupant safety
Warning!G
Modifications to or work improperly
conducted on restraint systems (such as
seat belts and anchors, emergency tension-
ing devices, seat belt force limiters or air
bags) or their wiring, as well as tampering
with interconnected electronic systems, can
lead to the restraint systems no longer func-
tioning as intended.
Air bags or emergency tensioning devices,
for example, could deploy inadvertently or
fail to deploy in accidents although the
deceleration threshold for air bag deploy-
ment is exceeded. Therefore, never modify
the restraint systems. Do not tamper with
electronic components or their software.
Warning!G
In the event that the 1indicator lamp
comes on during driving or does not come
on at all, the SRS self-check has detected a
malfunction. For your safety, we strongly
recommend that you contact an authorized
Mercedes-Benz Light Truck Center immedi-
ately to have the system checked; otherwise
the SRS may not deploy when needed in an
accident, which could result in serious or
fatal injury, or it might deploy unexpectedly
and unnecessarily which could also result in
injury.
In addition, improper work on the SRS
creates a risk of rendering the SRS inopera-
tive or causing unintended air bag deploy-
ment. Work on the SRS must therefore only
be performed by qualified technicians.
Contact an authorized Mercedes-Benz Light
Truck Center.
If it is necessary to modify an air bag system
to accommodate a person with disabilities,
contact a local authorized Mercedes-Benz
Light Truck Center or call our Customer
Assistance Center at 1-800-FOR-MERCedes
(1-800-367-6372) for details.

72 Safety and Security
Occupant safety
Air bags
Warning!G
Air bags are designed to reduce the poten-
tial of injury and fatality in certain frontal
impacts (front air bags), side impacts (side
impact air bags and window curtain air bags)
or rollovers (window curtain air bags).
However, no system available today can
completely eliminate injuries and fatalities.
The deployment of the air bags temporarily
releases a small amount of dust from the air
bags. This dust, however, is neither injurious
to your health, nor does it indicate a fire in
the vehicle. The dust might cause some tem-
porary breathing difficulty for people with
asthma or other breathing trouble. To avoid
this, you may wish to get out of the vehicle
as soon as it is safe to do so. If you have any
breathing difficulty but cannot get out of the
vehicle after the air bag inflates, then get
fresh air by opening a window or door.
Warning!G
To reduce the risk of injury when the front
air bags inflate, it is very important for the
driver and front passenger to always be in a
properly seated position and to wear their
respective seat belt.
For maximum protection in the event of a
collision always be in normal seated position
with your back against the seat backrest.
Fasten your seat belt and make sure it is
properly positioned on your body
(
page 50).
Since the air bag inflates with considerable
speed and force, a proper seating and hands
on steering wheel position will help to keep
you at a safe distance from the air bag.
Occupants who are unbelted, out of position
or too close to the air bag can be seriously
injured or killed by an air bag as it inflates
with great force in the blink of an eye:

Sit properly belted in a position that is
as upright as possible with your back
against the seat backrest.

Adjust the driver seat as far as possible
rearward, still permitting proper opera-
tion of vehicle controls. The distance
from the center of the driver’s breast-
bone to the center of the air bag cover
on the steering wheel must be at least
10 inches (25 cm) or more. You should
be able to accomplish this by a combina-
tion of adjustments to the seat and
steering wheel. If you have any
problems, please contact an authorized
Mercedes-Benz Light Truck Center.

Do not lean your head or chest close to
the steering wheel or dashboard.

Keep hands on the outside of steering
wheel rim. Placing hands and arms
inside the rim can increase the risk and
potential severity of hand/arm injury
when driver’s front air bag inflates.

Adjust the front passenger seat as far as
possible rearward from the dashboard
when the seat is occupied.

73 Safety and Security
Occupant safety

Always sit as upright as possible,
properly use the seat belts and use an
appropriately sized infant restraint,
toddler restraint, or booster seat recom-
mended for the size and weight of the
child.
Failure to follow these instructions can
result in severe injuries to you or other
occupants.
If you sell your vehicle, it is important that
you make the buyer aware of this safety
information. Be sure to give the buyer this
Operator’s Manual.Warning!G
Accident research shows that the safest
place for children in an automobile is in the
rear seat.
It should be noted that with respect to both,
front side impact air bags or the rear side
impact air bags*, there is a possibility for a
side impact air bag related injury if occu-
pants, especially children, are not properly
seated or restrained when next to a side im-
pact air bag which needs to deploy rapidly in
a side impact in order to do its job.
To help avoid the possibility of injury, please
follow these guidelines:
(1) Always sit as upright as possible,
properly use the seat belts and for
children 12 years old and under, use an
appropriately sized infant restraint,
toddler restraint, or booster seat recom-
mended for the size and weight of the
child.
(2) Always wear seat belts properly.
iAir bags are designed to deploy only in cer-
tain frontal impacts (front air bags), side impacts
(side impact and window curtain air bags)
which exceed preset thresholds, and in certain
rollovers (window curtain air bags). Only during
these events will they provide their supplemental
protection.
The driver and passengers should always wear
their seat belts. Otherwise it is not possible for
air bags to provide their supplemental protec-
tion.
In case of other types of impacts and impacts be-
low air bag deployment thresholds, air bags will
not deploy. The driver and passenger will then be
protected to the extent possible by a properly
fastened seat belt. A properly fastened seat belt
is also needed to provide the best possible pro-
tection in a rollover.
We caution you not to rely on the presence of the
air bags in order to avoid wearing your seat belt.
It is important to your safety and that of your
passengers that you replace deployed air bags
and repair any malfunctioning air bags to make
sure the vehicle will continue to provide supple-
mental crash protection for occupants.

74 Safety and Security
Occupant safety
Safety guidelines for the seat belt,
emergency tensioning device and
air bag
Warning!G

Damaged seat belts or belts that were
highly stressed in an accident must be
replaced and their anchoring points
must also be checked. Use only belts in-
stalled or supplied by an authorized
Mercedes-Benz Light Truck Center.

Air bags and pyrotechnic Emergency
Tensioning Devices (ETDs) are designed
to function on a one-time-only basis. An
air bag or ETD that is deployed must be
replaced.

Do not pass belts over sharp edges.
They could tear.

Do not make any modification that could
change the effectiveness of the belts.

Do not bleach or dye seat belts as this
may severely weaken them. In a crash
they may not be able to provide ade-
quate protection.

No modifications of any kind may be
made to any components or wiring of
the SRS. This includes changing or
removing any component or part of the
SRS, the installation of additional trim
material, badges, etc. over the steering
wheel hub, front passenger front air bag
cover, outboard sides of the front seat
backrests, door trim panels, or door
frame trims, and installation of addition-
al electrical/electronic equipment on or
near SRS components and wiring. Keep
area between air bags and occupants
free from objects (e.g. packages, purs-
es, umbrellas, etc.).

Do not hang items such as coat hangers
from the coat hooks or handles over the
door. These items may turn into projec-
tiles and cause head and other injuries
when the window curtain air bag is
deployed.

Air bag system components will be hot
after an air bag has inflated. Do not
touch.

Never place your feet on the instrument
panel, dashboard, or on the seat. Always
keep both feet on the floor in front of the
seat.

In addition, improper repair work on the
SRS creates a risk of rendering the SRS
inoperative or causing unintended air
bag deployment. Work on the SRS must
therefore only be performed by qualified
technicians. Contact an authorized
Mercedes-Benz Light Truck Center.

For your protection and the protection
of others, when scrapping the air bag
unit or emergency tensioning device,
our safety instructions must be fol-
lowed. These instructions are available
from your authorized Mercedes-Benz
Light Truck Center.

Given the considerable deployment
speed, required inflation volume, and
the textile structure of the air bags,
there is the possibility of abrasions or
potentially more serious injuries result-
ing from air bag deployment.

75 Safety and Security
Occupant safety
When you sell your vehicle we strongly
urge you to give notice to the subsequent
owner that it is equipped with an SRS by
alerting them to the applicable section in
the Operator’s Manual.Front air bags
1Driver air bag
2Passenger air bag
Driver and front passenger air bags are
deployed:

in the event of certain frontal impacts

if impact exceeds a preset deployment
threshold

independently of the side impact air
bags
Warning!G
Only use seat covers which have been test-
ed and approved by Mercedes-Benz for your
vehicle model. Using other seat covers may
interfere with or prevent the deployment of
the front side impact air bags or the rear
side impact air bags*. Contact an autho-
rized Mercedes-Benz Light Truck Center for
availability.
iThe front air bags in this vehicle have been
designed to inflate in two stages. This allows the
air bag to have different rates of inflation that are
based on the rate of relevant vehicle decelera-
tion as assessed by the air bag control unit.
On the front passenger-side, the front air bag
deployment is additionally influenced by the
passenger’s weight category as identified by the
Occupant Classification System (OCS)
(
page 77).
The lighter the front passenger side occupant,
the higher the vehicle deceleration rate required
for the second stage inflation of the air bag.

76 Safety and Security
Occupant safety
The air bags will not deploy in impacts
which do not exceed the system’s deploy-
ment thresholds. You will then be protec-
ted by the fastened seat belts.
The front passenger front air bag will only
be deployed if:

the system, based on OCS sensor read-
ings, senses that the front passenger
seat is occupied

the 59indicator lamp in
the center console is not lit
(
page 81)

the impact exceeds a preset deploy-
ment thresholdSide impact air bags, window curtain
air bags
1Front side impact air bag
2Window curtain air bag
3Rear side impact air bag
(second-row seats, USA only)
The side impact air bags and window
curtain air bags are deployed:

on the impacted side of the vehicle

in impacts exceeding a preset deploy-
ment threshold

independently of the front air bags
Warning!G
The pressure sensors for side impact air bag
control are located in the doors. Do not
modify any components of the doors or door
trim panels including, for example, the addi-
tion of door speakers.
Improper repair work on the doors or the
modification or addition of components to
the doors creates a risk of rendering the
side impact air bags inoperative or causing
unintended air bag deployment. Work on the
doors must therefore only be performed by
qualified technicians. Contact an authorized
Mercedes-Benz Light Truck Center.

77 Safety and Security
Occupant safety
In addition, the window curtain air bags2
are deployed in certain vehicle rollovers.
The front passenger side impact air bag
will not deploy if the OCS senses that the
front passenger seat is empty and the front
passenger seat belt is not fastened (latch
plate is not inserted into the buckle). With
an empty front passenger seat and the
seat belt fastened (latch plate properly in-
serted into buckle) the front passenger
side impact air bag will deploy indepen-
dently of the empty seat.
The side impact air bags and window cur-
tain air bags are not deployed in impacts
which do not exceed the system’s deploy-
ment threshold.Occupant Classification System
The Occupant Classification System (OCS)
automatically turns the front passenger
front air bag on or off based on the classi-
fied occupant weight category determined
by weight sensor readings from the front
passenger seat.
Occupants must sit properly belted in a
position that is as upright as possible with
their back against the seat backrest and
feet on the floor to be correctly classified.
If the occupant’s weight is transferred to
another object in the vehicle (e.g. by lean-
ing on armrests), the OCS may not be able
to properly approximate the occupant’s
weight category.Furthermore, the occupant weight may
appear to increase or decrease due to
objects hanging on the seat, other passen-
gers pushing on the seat, objects lodged
underneath the seat or stuffed between
seat and middle console or between seat
and door or due to objects applying pres-
sure on the back of the seat. Always make
sure the seat has clearance in all direc-
tions at all times.
Both, driver and the front passenger
should always use the 59 in-
dicator lamp as an indication of whether or
not the front passenger is properly posi-
tioned.
iThe system does not deactivate the front
passenger side impact air bag, the window cur-
tain air bag, and the emergency tensioning de-
vice.
iIf your seat, including your trim cover and
cushion needs to be serviced in any way, take
the vehicle to an authorized Mercedes-Benz
Light Truck Center.
Only seat accessories approved by
Mercedes-Benz may be used.

78 Safety and Security
Occupant safety
Warning!G
If the 59indicator lamp illumi-
nates when an adult or someone larger than
a small individual is in the front passenger
seat, have the front passenger reposition
himself or herself in the seat until the
59 indicator lamp goes out, or
check whether objects are caught under or
around the seat.
More information about air bag display
messages (
page 438).
In the event of a collision, the air bag control
unit will not allow front passenger front air
bag deployment when the OCS classified
the front passenger seat occupant as being
up to or less than the weight of a typical
12-month-old child in a standard child re-
straint or if the front passenger seat is
sensed as being empty.
When the OCS senses that the front passen-
ger seat occupant is classified as being up
to or less than the weight of a typical
12-month-old child in a standard child
restraint, the 59indicator
lamp will illuminate when the engine is
started and remain illuminated, indicating
that the front passenger front air bag is de-
activated.
When the OCS senses that the front passen-
ger seat is classified as being empty, the
59indicator lamp will illumi-
nate when the engine is started and remain
illuminated, indicating that the front passen-
ger front air bag is deactivated.When the OCS senses that the front passen-
ger seat occupant is classified as being
heavier than the weight of a typical
12-month-old child seated in a standard
child restraint or as being a small individual
(such as a young teenager or a small adult),
the 59 indicator lamp will illu-
minate for approximately 6 seconds when
the engine is started and then, depending on
occupant weight sensor readings from the
seat, remain illuminated or go out. With the
59 indicator lamp illuminated,
the front passenger front air bag is deacti-
vated. With the 59indicator
lamp out, the front passenger front air bag is
activated.
When the OCS senses that the front passen-
ger seat occupant is classified as an adult or
someone larger than a small individual, the
59 indicator lamp will illumi-
nate for approximately 6 seconds when the
engine is started and then go out, indicating
that the front passenger front air bag is acti-
vated.

79 Safety and Security
Occupant safety
If the 59indicator lamp is illu-
minated, the front passenger front air bag is
deactivated and will not be deployed.
If the 59indicator lamp is not
illuminated, the front passenger front air
bag is activated and will be deployed:

in the event of certain frontal impacts

if impact exceeds a preset deployment
threshold

independently of the side impact air
bags.
If the front passenger front air bag is de-
ployed, the rate of inflation will be influ-
enced by

the rate of relevant vehicle deceleration
as assessed by the air bag control unit

the front passenger’s weight category
as identified by the Occupant Classifica-
tion System (OCS)
Warning!G
According to accident statistics, children
are safer when properly restrained in the
rear seating positions than in the front seat-
ing position. Thus, we strongly recommend
that children be placed in the rear seats
whenever possible. Regardless of seating
position, children 12 years old and under
must be seated and properly secured in an
appropriate infant or child restraint recom-
mended for the size and weight of the child.
The infant or child restraint must be properly
secured with the vehicle’s seat belt, the seat
belt and top tether strap, or lower anchors
and top tether strap, fully in accordance
with the child seat manufacturer’s instruc-
tions.
Children can be killed or seriously injured by
an inflating air bag. Note the following im-
portant information when circumstances re-
quire you to place a child in the front
passenger seat:

Your vehicle is equipped with air bag
technology designed to turn off 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 appropri-
ate child restraint on the front passen-
ger seat.

A child in a rear-facing child restraint on
the front passenger seat will be serious-
ly injured or even killed if the front pas-
senger front air bag inflates in a collision
which could occur under some circum-
stances, even with the air bag tech-
nology installed in your vehicle. The only
means to completely eliminate this risk
is to never place a child in a rear-facing
child restraint in the front seat. We
therefore strongly recommend that you
always place a child in a rear-facing
child restraint in the back seat.