
Occupant Classification System
(OCS)
Method of operation G
WARNING
If the 45 indicator lamp illuminates
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 45
indicator lamp goes out.
In the event of a collision, the air bag control
unit will not allow front passenger front air bag
deployment when the OCS has classified the
front passenger seat occupant as weighing as
much as or less than a typical 12-month-old
child in a standard child restraint or if the front
passenger seat is classified as being empty.
When the OCS senses that the front
passenger 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 45 indicator lamp will
illuminate when the engine is started and
remain illuminated. This indicates that the
front passenger front air bag is deactivated.
When the OCS senses that the front
passenger seat is classified as being empty,
the 45 indicator lamp will illuminate
when the engine is started and remain
illuminated. This indicates that the front
passenger front air bag is deactivated.
When the OCS senses that the front
passenger 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
45 indicator lamp will illuminate for
approximately 6 seconds when the engine is
started. Depending on occupant weight
sensor readings from the seat, it will then
remain illuminated or go out. With the
45 indicator lamp illuminated, the
front passenger front air bag is deactivated. With the 45 indicator lamp out, the
front passenger front air bag is activated.
When the OCS senses that the front
passenger seat occupant is classified as an
adult or someone larger than a small
individual, the
45 indicator lamp will
illuminate for approximately six seconds
when the engine is started and then go out.
This indicates that the front passenger front
air bag is activated.
If
the 45 indicator lamp is illuminated,
the front passenger front air bag is
deactivated and will not be deployed.
If the 45 indicator lamp is not
illuminated, the front passenger front air bag
is activated and will be deployed
R in the event of certain frontal impacts
R if the impact exceeds a predetermined
triggering threshold
R independent of the side impact air bag or
pelvis air bag
If the front passenger front air bag is
deployed, the rate of inflation will be
influenced by
R the rate of vehicle deceleration as assessed
by the air bag control unit
R the front passenger's weight category as
identified by the OCS G
WARNING
According to accident statistics, children are
safer when properly restrained on the rear
seats
than on the front-passenger seat. 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
restraint, toddler restraint, or booster seat
recommended 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 48
Occupant safety
Safety

and Top Tether strap, fully in accordance with
the child seat manufacturer's instructions.
Occupants,
especially children, should always
sit as upright as possible, wear the seat belt
properly and use an appropriately sized infant
restraint, toddler restraint, or booster seat
recommended for the size and weight of the
child.
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
45 indicator lamp is illuminated,
indicating that the front-passenger front air
bag is deactivated. Should the 45
indicator lamp not illuminate or go out while
the restraint is installed, please check
installation. Periodically check the
45 indicator lamp while driving to
make sure that the 45 indicator
lamp is illuminated. If the 45
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 the typical 12-
month-old child, the front-passenger front
air bag may or may not be activated. G
WARNING
If the red 6 SRS warning lamp in the
instrument cluster and the 45
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 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. Occupant safety
49
Safety Z

If the SmartKey has been removed from the
ignition lock or is in position 0, the
45 indicator lamp
: does not light
up.
The Occupant Classification System (OCS)
categorizes the occupant on the front-
passenger seat using a weight sensor. The
front-passenger front air bag is deactivated
automatically for certain weight categories.
45 indicator lamp : shows you the
current status. If
45 indicator lamp : lights up, the
front-passenger air bag is disabled.
The system does not deactivate:
R the side impact air bag
R the pelvis air bag
R the window curtain air bag
R the Emergency Tensioning Devices
To
be classified correctly, the front passenger
must sit:
R with the seat belt fastened correctly
R in a position that is as upright as possible
with their back against the seat backrest
R with their feet on the floor
The OCS weight sensor reading is affected if
the occupant's weight is transferred, e.g. by
leaning on the armrest.
If the front-passenger seat, the seat cover or
the seat cushion are damaged, have the
necessary repair work carried out at a
qualified specialist workshop.
For safety reasons, Mercedes-Benz
recommends that you only use seat accessories that have been approved by
Mercedes-Benz.
Both the driver and the front passenger
should always observe the
45
indicator lamp to determine whether or not
the front passenger is positioned correctly.
Also observe the air bag display messages,
which appear in the instrument cluster
(Y page 253).
If the driver's air bag deploys, this does not
mean that the front-passenger front air bag
will also deploy.
The OCS may have detected that the seat:
R is empty or occupied by the weight of a
typical child up to twelve months old,
seated in a child restraint system
R is
occupied by a small individual, such as a
young teenager or a small adult
R is occupied by a child in a child restraint
system whose weight is greater than that
of a typical twelve 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.
For further information, see "Air bag display
messages" ( Y page 253).
System self-test G
WARNING
If the 4 5 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. G
WARNING
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 50
Occupant safety
Safety

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.
The 45 indicator lamp lights up:
R if you turn the SmartKey in the ignition lock
to position 1 or 2
R if you press the KEYLESS-GO Start/Stop
button once or twice on vehicles with
KEYLESS-GO
R if an adult is seated properly on the front-
passenger seat and the OCS classifies the
occupant as an adult
The 45 indicator lamp goes out
after approximately six seconds.
If the seat is not occupied and the OCS
detects that the front-passenger seat is
empty, the 45 indicator lamp will
continue to light up. The 45 front-
passenger front air bag warning lamp then
stays lit continuously.
For more information about the OCS, see
"Problems with the Occupant Classification
System" ( Y page 52). Occupant safety
51
Safety Z

NECK-PRO head restraints/NECK-
PRO luxury head restraints
Important safety notes G
WARNING
Do not attach any objects (e.g. a coat hanger)
to the NECK-PRO head restraints/NECK-PRO
luxury head restraints. Otherwise, the NECK-
PRO head restraints/NECK-PRO luxury head
restraints may not function properly and in
the event of a rear-end collision may not offer
the protection they are designed to provide. G
WARNING
Seat or head restraint covers can cause a
malfunction when the NECK-PRO head
restraints/NECK PRO luxury head restraints
are
activated or when the side impact air bags
or pelvis air bags are deployed, or they can
prevent this completely. The NECK-PRO head
restraints/NECK PRO luxury head restraints
or side impact air bags/pelvis air bags can
therefore not provide the intended protection.
Do not use any seat or head restraint covers. G
WARNING
For your protection, drive only with properly
positioned head restraints.
Adjust
the head restraint so that it is as close
to the head as possible and the center of the
head restraint supports the back of the head
at eye level. This will reduce the potential for
injury to the head and neck in the event of an
accident or similar situation. G
WARNING
For reasons of safety, have the NECK-PRO
head restraints/NECK-PRO luxury head
restraints checked at an authorized
Mercedes-Benz Center after a rear-end
collision.
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.
If the NECK-PRO head restraints/NECK-PRO
luxury head restraints have been triggered in
an accident, reset the NECK-PRO head
restraints/NECK-PRO luxury head restraints
on the driver's and front-passenger seats
(Y page 54). Otherwise, the additional
protection will not be available in the event of
another rear-end collision. NECK-PRO head
restraints/NECK-PRO luxury head restraints
that have been triggered are moved forwards
and can no longer be adjusted.
Resetting triggered NECK-PRO head
restraints/NECK-PRO luxury head
restraints NECK-PRO head restraints
G
WARNING
When pushing back the NECK-PRO head
restraint cushion, make sure your fingers do
not become caught between the head
restraint cushion and the cover. Failure to
observe this could result in injuries. NECK-PRO head restraints (example: Sedan)
X
Tilt the top of the NECK-PRO head restraint
cushion forwards in the direction of
arrow :.
X Push the NECK-PRO head restraint cushion
down
in the direction of arrow ; as far as
it will go. Occupant safety
53
Safety Z

X
Firmly push the NECK-PRO head restraint
cushion back in the direction of arrow =
until the cushion engages.
X Repeat this procedure for the second
NECK-PRO head restraint.
i Resetting the NECK-PRO head restraints
requires a lot of strength. If you have
difficulty resetting the NECK-PRO head
restraints, have this work carried out at a
qualified specialist workshop.
NECK-PRO luxury head restraints NECK-PRO luxury head restraints
X
Remove resetting tool : from the vehicle
document wallet.
X Slide resetting tool : into guide ;
between the NECK-PRO luxury head
restraint and the rear cover of the head
restraint.
X Push resetting tool : downwards until you
hear the head restraint deployment
mechanism engage.
X Pull out resetting tool :.
X Firmly press the NECK-PRO luxury head
restraint cushion back = until it engages.
X Repeat this procedure for the second
NECK-PRO luxury head restraint.
X Put resetting tool : back into the vehicle
document wallet.
i If you have difficulty resetting the NECK-
PRO
luxury head restraints, have this work
carried out at a qualified specialist
workshop. PRE-SAFE
®
system G
WARNING
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. G
WARNING
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.
PRE-SAFE ®
takes preemptive measures to
protect occupants in certain hazardous
situations.
PRE-SAFE ®
intervenes:
R if BAS intervenes, e.g. in emergency
braking situations
R if, on vehicles with DISTRONIC PLUS, BAS
PLUS intervenes powerfully
R if, on vehicles with DISTRONIC PLUS, the
radar sensor system detects an imminent
danger of collision in certain situations
R in critical driving situations, e.g. when
physical limits are exceeded 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 the front-passenger seat is adjusted if it is
in an unfavorable position.54
Occupant safety
Safety

R
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.
R When using a seat belt to secure infant
restraints, toddler restraints, or children in
booster seats, always follow the child seat
manufacturer's instructions. G
WARNING
Do not pass seat belts over sharp edges. They
could tear.
Do
not allow the seat belt to get caught in the
door or in the seat adjustment mechanism.
This could damage the seat belt.
Never attempt to make modifications to seat
belts. This could impair the effectiveness of
the seat belts.
Fastening seat belts G
WARNING
According to accident statistics, children are
safer when properly restrained on the rear
seats
than on the front-passenger seat. Thus,
we strongly recommend that children be
placed in the rear seat whenever possible.
Regardless of seating position, children 12
years old and under must be seated and
properly secured in an appropriately sized
child restraint system or booster seat
recommended for the size and weight of the
child. For additional information, see the
"Children in the vehicle" section.
A child's risk of serious or fatal injuries is
significantly increased if the child restraints
are not properly secured in the vehicle and/
or the child is not properly secured in the child
restraint. Example: Sedan
X
Adjust the seat and move the backrest to
an almost vertical position ( Y page 102).
X Pull the seat belt smoothly through belt
sash guide :.
X Without twisting it, guide the shoulder
section of the seat belt across the middle
of
your shoulder and the lap section across
your pelvis.
X Engage belt tongue ; in buckle =.
Seat-belt adjustment: if necessary, the
driver's and front-passenger seat belts
automatically adjust to the upper body
(Y page 58).
X If necessary, adjust the seat belt to the
appropriate height
(Y page 58).
X If necessary, pull upwards on the shoulder
section of the seat belt to tighten the belt
across your body.
All seat belts except the driver's seat belt are
equipped
with a special seat belt retractor to
securely fasten child restraint systems in the
vehicle. Further information can be found
under "Special seat belt retractor"
(Y page 63).
For more information about releasing the seat
belt with release button ?, see "Releasing
seat belts" ( Y page 58). Occupant safety
57
Safety Z

Example: Sedan
X
Press release button ? on belt buckle =.
X Slide belt tongue ; back to belt sash
guide :.
Belt warning for the driver and front
passenger Regardless of whether the driver's and front-
passenger seat belts have already been
fastened, the 7 seat belt warning lamp
lights
up for six seconds each time the engine
is started. 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 when
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.
If after six seconds the driver or front
passenger have not fastened their seat belts
and the doors are closed, the 7 seat belt
warning lamp lights up:
R until the driver's or front passenger's seat
belt is fastened
R once the vehicle has exceeded a speed of
15 mph (25 km/h), in addition a warning
tone will sound with increasing intensity for up to 60 seconds or until the driver's or
front-passenger seat belt is fastened.
If the driver/front passenger unfasten their
seat belt while the vehicle is in motion, the
7 seat belt warning lamp lights up and a
warning tone sounds again.
The warning tone ceases after 60 seconds
even if the driver or front passenger has still
not fastened their seat belt. The 7 seat
belt
warning lamp stops flashing but remains
illuminated.
After the vehicle comes to a standstill, the
warning tone is reactivated and the 7 seat
belt warning lamp flashes again if the vehicle
speed again exceeds 15 mph (25 km/h).
The 7 seat belt warning lamp only goes
out if:
R both the driver and the front passenger
have fastened their seat belts.
or
R the vehicle is stationary and a door is open.
i For more information on the 7 seat
belt warning lamp, see "Warning and
indicator lamps in the instrument cluster,
seat belts" ( Y page 276).
Emergency Tensioning Devices, belt
force limiters G
WARNING
Pyrotechnic Emergency Tensioning Devices
that have been deployed must be renewed.
For
your safety, when disposing of Emergency
Tensioning Devices, always observe the
safety instructions. These are available from
any authorized Mercedes-Benz Center.
The PRE-SAFE ®
system has electrically
operated reversible pre-tensioners that do
not require replacement after activation.
! If the front-passenger seat is not
occupied, do not engage the seat belt
tongue in the buckle on the front-
passenger seat. Otherwise, the Emergency Occupant safety
59
Safety Z