2008 MERCEDES-BENZ C300 4MATIC ECU

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

Damaged seat belts or seat belt that
were highly stressed in an accident
must be replaced and their anchoring
points must also be checked. Only use
seat belts installed or supplied at an au-
thorized Mercedes-Benz Center.

Air bags and Emergency Tensioning
Devices (ETDs) contain Perchlorate
material, which may require special han-
dling and regard for the environment.
Check with your local government’s dis-
posal guidelines. California residents,
see http://www.dtsc.ca.gov/Hazard-
ousWaste/Perchlorate/index.cfm.

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 seat belt over sharp edges.
They could tear.

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

39 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
2Front passenger front air bag
The front air bags are designed to provide
increased protection for the driver and
front passenger against the risk of injuries
to the head and thorax.
Driver and front passenger front air bag are
deployed:
in the event of certain frontal impacts

if impact exceeds a preset deployment
threshold

if the system determines that airbag
deployment can offer additional pro-
tection to that provided by the seat belt

depending on whether the seat belt is
in use

independently of the front side impact
air bags, rear side impact air bags*
and/or the window curtain air bags.

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
Center.

Given the considerable deployment
speed, required inflation volume, and
the textile structure of the air bags,
there is the possibility of abrasions or
other, potentially more serious injuries
resulting from air bag deployment.
Warning!G
Only use seat covers which have been
tested 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
authorized Mercedes-Benz Center for avail-
ability.
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 de-
ployment is additionally influenced by the pas-
senger’s weight category as identified by the
Occupant Classification System (OCS)
(
page 41).
The lighter the front passenger-side occupant,
the higher the vehicle deceleration rate required
for the second stage inflation of the air bag.

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.