MERCEDES-BENZ C300 SPORT 2008 W204 Service Manual

40 Safety and Security
Occupant safety
The front air bags will not deploy in im-
pacts which do not exceed the system’s
deployment thresholds. You will then be
protected by the fastened seat belts.
The front airbags are not deployed in the
event of a rollover unless the vehicle's rate
of longitudinal deceleration or acceleration
exceeds the preset deployment threshold
for the front air bags.
The front passenger front air bag2
(
page 39) will only be deployed if:

the system, based on OCS weight sen-
sor readings, senses that the front
passenger seat is occupied

the 5/indicator lamp in the
center console is not lit (
page 45)

the impact exceeds a preset deploy-
ment thresholdFront side impact air bags and rear side
impact air bags*
1Front side impact air bag
2Rear side impact air bag*
When deployed, the front side impact air
bags1 and/or the rear side impact air
bags*2 are designed to provide in-
creased protection for the thorax (but not
the head, neck and arms) of the occupants
on the side of the vehicle on which the im-
pact occurs.The front side impact air bags1 and the
rear side impact air bags*2 are
deployed:

on the impacted side of the vehicle

in impacts exceeding a preset deploy-
ment threshold

independently of the front air bags
The front passenger front side impact air
bag1 will not deploy if the OCS senses
that the front passenger seat is empty and
the front passenger seat belt is not fas-
tened (latch plate is not inserted into the
buckle). With an empty front passenger
seat and the seat belt fastened (latch plate
properly inserted into buckle) the front
passenger side impact air bag1 will
deploy regardless of the empty seat.
The front side impact air bags1 and the
rear side impact air bags*2 are not de-
ployed in impacts which do not exceed the
system’s deployment threshold.

41 Safety and Security
Occupant safety
Window curtain air bags
1Window curtain air bag
When deployed, the window curtain air
bags1 are designed to provide increased
protection for the head (but not the chest
or arms) of the occupants on the side of
the vehicle on which the impact occurs.
The window curtain air bags fill up the area
indicated by the arrows.The 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

regardless of whether the front-pas-
senger seat is occupied

in certain vehicle rollovers
The side window curtain air bags are not
deployed in impacts which do not exceed
the system’s deployment 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.
iThe system does not deactivate the front
passenger side impact air bag, the window cur-
tain air bag and the emergency tensioning de-
vice.

42 Safety and Security
Occupant safety
Both driver and the front passenger should
always use the 5/indicator lamp
as an indication of whether or not the front
passenger is properly positioned.
iIf your seat, including your trim cover and
cushion needs to be serviced in any way, take
the vehicle to an authorized Mercedes-Benz
Center.
Only seat accessories approved by
Mercedes-Benz may be used.Warning!G
If the 5/indicator lamp illuminates
when an adult or someone larger than a
small individual is in the front passenger
seat, have the front passenger re-position
himself or herself in the seat until the
5/indicator lamp goes out, or check
whether objects are caught under or around
the seat.
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
restraint 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 5/indicator lamp will
illuminate when the engine is started and
remain illuminated, indicating that the front
passenger front air bag is deactivated.
When the OCS senses that the front passen-
ger seat is classified as being empty, the
5/indicator lamp will illuminate
when the engine is started and remain
illuminated, indicating that the front
passenger 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 5/indicator lamp will illuminate
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
5/indicator lamp illuminated, the
front passenger front air bag is deactivated.
With the 5/indicator lamp out, the
front passenger front air bag is activated.

43 Safety and Security
Occupant safety
More information about air bag display
messages (
page 393).
When the OCS senses that the front passen-
ger seat occupant is classified as an adult or
someone larger than a small individual, the
5/indicator lamp will illuminate for
approximately 6 seconds when the engine is
started and then go out, indicating that the
front passenger front air bag is activated.
If the 5/indicator lamp is
illuminated, the front passenger front air
bag is deactivated and will not be deployed.
If the 5/indicator 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 front side impact
air bags and/or rear side impact air
bags*.
If the front passenger front air bag is
deployed, the rate of inflation will be
influenced by:

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

front passenger’s weight category as
identified by the Occupant Classification
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
instructions.
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
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 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.


44 Safety and Security
Occupant safety

If you must install a rear-facing child
restraint on the front passenger seat
because circumstances require you to
do so, make sure the 5/ indica-
tor lamp is illuminated, indicating that
the front passenger front air bag is deac-
tivated. Should the 5/indicator
lamp not illuminate or go out while the
restraint is installed, please check in-
stallation. Periodically check the
5/ indicator lamp while driving
to make sure the 5/indicator
lamp is illuminated.
If the 5/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.
If you have to 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, and
secure child restraint with the vehicle’s
seat belt according to the child seat
manufacturer’s instructions. For
children larger than the typical
12-month-old child, the front passenger
front air bag may or may not be
activated.iDeployment of the driver front air bag does
not mean that the front passenger front air bag
also should have deployed.
The Occupant Classification System (
page 41)
may have determined:

that the seat was empty or occupied by the
weight up to or less than that of a typical
12-month-old child seated in a standard
child restraint – both instances where the
system suppresses deployment of the front
passenger front air bag even though the im-
pact met the criteria and was of sufficient
severity to deploy the driver front air bag.

that the seat was occupied by a small individ-
ual (such as a young teenager or a small
adult) or a child weighing more than the
weight of a typical 12-month-old child in a
standard child restraint – instances where
the system may suppress deployment of the
front passenger front air bag even though
the impact met the criteria and was of suffi-
cient severity to deploy the driver front air
bag.


45 Safety and Security
Occupant safety
1Front passenger front air bag off
indicator lamp
The
5/indicator lamp1 will be
illuminated, except with the SmartKey
removed from the starter switch or with
the starter switch in position0.Self-test Occupant Classification
System
After turning the SmartKey in the starter
switch to position1 or2 or pressing the
KEYLESS-GO* start/stop button (Canada
only) once or twice, the
5/ indicator
lamp1 illuminates. If an adult occupant is
properly sitting on the front passenger
seat and the system senses the occupant
as being an adult, the
5/ indicator
lamp will illuminate and go out after ap-
proximately 6 seconds.
If the seat is not occupied and the system
senses the front passenger seat as being
empty, the
5/indicator lamp will
illuminate and not go out.
Warning!G
If the =indicator lamp and the
5/indicator lamp are lit at the same
time, there is a malfunction in the Occupant
Classification System. The front passenger
front air bag will be deactivated in this case.
Have the system checked as soon as possi-
ble by qualified technicians. Contact an au-
thorized 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:

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

While seated, an occupant should not
position him/herself in such a way as to
cause the occupant’s weight to be lifted
from the seat bottom as this may result
in the OCS being unable to correctly ap-
proximate the occupant’s weight
category.

Read and observe all warnings in this
chapter.Warning!G
If the 5/indicator lamp should not il-
luminate, the system is not functioning. You
must see an authorized Mercedes-Benz
Center before seating any child on the front
passenger seat.

46 Safety and Security
Occupant safety
For more information, see the “Practical
hints” section (
page 385).
Seat belts
The use of seat belts and infant and child
restraint systems is required by law in all
50 states, the District of Columbia, the
U.S. territories and all Canadian provinces.
Even where this is not the case, all vehicle
occupants should have their seat belts fas-
tened whenever the vehicle is in motion.
For more information, see “Fastening the
seat belts” (
page 105).
Warning!G
Never place anything between seat cushion
and child seat (e.g. pillow), since it reduces
the effectiveness of the Occupant Classifi-
cation System. The bottom of the child seat
must make full contact with the passenger
seat cushion. An incorrectly mounted child
seat could cause injuries to the child in case
of an accident, instead of increasing protec-
tion for the child.
Follow the manufacturer’s instructions for
installation of child seats.
iFor information on infants and children trav-
eling with you in the vehicle and restraint sys-
tems for infants and children, see “Children in
the vehicle” (
page 51).
Warning!G
Always fasten your seat belt before driving
off. Always make sure all of your passengers
are properly restrained.
Failure to wear and properly fasten and po-
sition your seat belt greatly increases your
risk of injuries and their likely severity in an
accident. You and your passengers should
always wear seat belts.
If you are ever in an accident, your injuries
can be considerably more severe without
your seat belt properly buckled.
Without your seat belt buckled, you are
much more likely to hit the interior of the ve-
hicle or be ejected from it. You can be seri-
ously injured or killed.
In the same crash, the possibility of injury or
death is lessened if you are properly wearing
your seat belt. Air bags can only protect as
they are designed for, if the occupants are
properly wearing their seat belts.

47 Safety and Security
Occupant safety
Warning!G
Never ride in a moving vehicle with the seat
backrest in an excessively reclined position
as this can be dangerous. You could slide
under the seat belt in a collision. If you slide
under it, the seat belt would apply force at
the abdomen or neck. That could cause se-
rious or even fatal injuries. The seat back-
rest and seat belt provide the best restraint
when the wearer is in a nearly upright posi-
tion and the seat belt is properly positioned
on the body.
Warning!G
Never let more people ride in the vehicle
than there are seat belts available. Make
sure everyone riding in the vehicle is cor-
rectly restrained with a separate seat belt.
Never use a seat belt for more than one per-
son at a time.
Warning!G
Damaged seat belts or seat belts that were
highly stressed in an accident must be re-
placed 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 failure.
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.
Warning!G
USE SEAT BELTS PROPERLY

Seat belts can only work when used
properly. Never wear seat belts in any
other way than as described in this sec-
tion, as that could result in serious inju-
ries in case of an accident.

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, includ-
ing rollovers. The integrated restraint
system includes SRS (driver air bag, pas-
senger front air bag, front side impact
air bags, rear side impact air bags*, win-
dow curtain air bags for side windows),
ETD (seat belt emergency tensioning de-
vice with seat belt force limiters), and
front seat knee bolsters. The system is
designed to enhance the protection of-
fered to properly belted occupants in
certain frontal (front air bags and ETD)
and side (front side impact air bags, rear
side impact air bags*, window curtain
air bags and ETD)


48 Safety and Security
Occupant safety
Enhanced seat belt reminder system
When the engine is started, the seat belt
telltale< will always illuminate for
6 seconds to remind you and your passen-
gers to fasten your seat belts.
If the driver’s seat belt is not fastened
when the engine is started, an additional
warning chime will also sound for a maxi-
mum of 6 seconds or until the driver’ s
seat belt is fastened.
If after these 6 seconds the driver’s or the
front passenger’s seat belt (with the front
passenger seat occupied) is not fastened
with front doors closed,

the seat belt telltale< remains illu-
minated for as long as either the driv-
er’s or front passenger’s seat belt is not
fastened.

and if the vehicle speed once exceeds
15 mph (25 km/h), the seat belt
telltale< starts flashing and a
warning chime sounds with increasing
impacts which exceed preset deploy-
ment thresholds and in certain rollovers
(window curtain air bags and ETD).

Never wear the shoulder belt under your
arm, against your neck or off your shoul-
der. 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.

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.

Position the lap belt as low as possible
on your hips and not across the abdo-
men. If the seat belt is positioned across
your abdomen, it could cause serious
injuries in a crash.

Never use a seat belt for more than one
person at time. Do not fasten a seat belt
around a person and another person or
other objects.

Seat belts should not be worn twisted.
In a crash, you wouldn’t have the full
width of the seat belt to distribute
impact forces. The twisted seat belt
against your body could cause injuries.

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.

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.

When using a seat belt to secure infant
restraint, toddler restraint, or booster
seat, always follow the child seat manu-
facturer’s instructions.


49 Safety and Security
Occupant safety
intensity for a maximum of 60 seconds
or until the driver’s and the front
passenger’s seat belt are fastened.
If you and/or your front passenger
release the seat belt during driving, the
seat belt telltale< starts flashing
and a warning chime sounds as
described before.
If the driver’s or the front passenger’s
seat belt remains unfastened after
60 seconds, the warning chime stops
sounding, the seat belt telltale<
stops flashing but continues to be
illuminated.
After a vehicle standstill, the warning
chime reactivates and the seat belt
telltale< flashes again when the
vehicle speed exceeds 15 mph
(25 km/h).
The seat belt telltale< will only go out
if both the driver’s and the front passen-
ger’s seat belt (with the front passenger
seat occupied) are fastened, or the vehicle
is standing still and a front door is opened.For more information, see “Practical hints”
(
page 380).
Emergency tensioning device (ETD),
seat belt force limiter
The seat belts are equipped with Emergen-
cy Tensioning Devices (ETDs) and seat belt
force limiters.
The ETD is designed to activate in the
following cases:

in frontal or rear-end impacts exceed-
ing the system deployment threshold

in certain vehicle rollovers

if the restraint systems are operational
and functioning correctly,
see=indicator lamp (
page 382)In an impact, the ETDs remove slack from
the seat belts in such a way that the seat
belts fit more snugly against the body. Seat
belt force limiters, when activated, are em-
ployed to help reduce the peak force exert-
ed by the seat belts on occupants during a
crash.
iThe ETDs for the front seats will only acti-
vate if the front seat belt is fastened (latch plate
properly inserted into buckle).
The ETDs for the rear seats will activate with or
without the respective seat belt fastened.
iETDs do not correct an incorrect seat posi-
tion or incorrectly worn seat belts.
ETDs do not pull occupants back toward the
backrest.
Warning!G
A pyrotechnic Emergency Tensioning Device
(ETD) that was activated must be replaced.
When disposing of the pyrotechnic Emer-
gency Tensioning Device (ETD), our safety
instructions must be followed. These are
available at an authorized Mercedes-Benz
Center.