How the occupant classification system works
The Occupant Classification System (OCS) categorizes the occupant on the frontpassenger seat by means of a weight sensor.
The front-passenger front air bag is deactivated automatically for certain weight categories. The indicator lamp shows you the current status. If the indicator lamp is illuminated, the front-passenger front air bag is deactivated.
The system does not deactivate:
• the side impact air bag
• the window curtain air bag
• the Emergency Tensioning Devices
To be classified correctly, the front passenger must sit:
• with the seat belt fastened correctly
• in a position that is as upright as possible with their back against the seat
backrest
• with their feet on the floor
If the front-passenger's weight is transferred to another object in the vehicle (e.g. by leaning on armrests), OCS may not be able to approximate the occupant's weight category.
If the front-passenger seat, the seat cover or the seat cushion are damaged, have the necessary repair work carried out at an authorized Mercedes-Benz Center.
For safety reasons, Mercedes-Benz recommends that you only use seat accessories which have been approved by Mercedes-Benz.
Both the driver and the passenger should always use the indicator lamp as an indication of whether or not the passenger is properly positioned.
WARNING
If the indicator lamp lights
up
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
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 frontpassenger
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 indicator
lamp
will illuminate when the engine is started and
remain illuminated, indicating that the frontpassenger
front air bag is deactivated.
When the OCS senses that the frontpassenger
seat is classified as being empty,
the indicator lamp will
illuminate when the engine is started and
remain illuminated, indicating that the frontpassenger
front air bag is deactivated.
When the OCS senses that the frontpassenger
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
indicator lamp will
illuminate
for approximately 6 seconds when the engine
is started and then, depending on occupant
weight sensor readings from the frontpassenger
seat, remain illuminated or go out.
With the indicator lamp
illuminated, the front-passenger front air bag
is deactivated. With the
indicator lamp out, the front-passenger front
air bag is activated.
When the OCS senses that the frontpassenger
seat occupant is classified as an
adult or someone larger than a small
individual, the 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 indicator lamp is
illuminated, the front-passenger front air bag
is deactivated and will not be deployed.
If the indicator lamp is not
illuminated, the front-passenger front air bag
is activated and will be deployed:
• in the event of certain frontal impacts
• impact exceeds a preset deployment threshold
• independently of the side impact air bags
If the front-passenger front air bag is deployed, the rate of inflation will be
influenced by:
• the rate of vehicle deceleration as assessed by the air bag control unit
• the front passenger's weight category as identified by OCS
For further information, see "Air bag display messages".
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 appropriately sized
child restraint system or booster seat
recommended for the size and weight of the
child.
The infant or child restraint system 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.
Occupants, especially children, should always
sit as upright as possible, wear the seat belt
properly and use an appropriate 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 frontpassenger
seat:
• 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.
• 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 frontpassenger
seat. We therefore strongly
recommend that you always place a child
in a rear-facing child restraint on the rear
seat.
• If you install a rear-facing child restraint on
the front-passenger seat, make sure the
indicator lamp is
illuminated, indicating that the frontpassenger
front air bag is deactivated.
Should the indicator lamp
not illuminate or go out while the restraint
is installed, please check installation.
Periodically check the
indicator lamp while driving to make sure
the indicator lamp is
illuminated. If the
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 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
• For children larger than a typical 12-monthold 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:
• 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
• was occupied by a small individual, such as
a young teenager or a small adult
• 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 1 does not light up.
WARNING
If the red SRS indicator
lamp in the
instrument cluster and the
indicator lamp are lit at the same time, there
is a malfunction in the OCS. 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:
• Sit with the seat belt properly fastened in a
position that is as upright as possible with
your back against the seat backrest.
• 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.
• Read and observe all warnings in this
chapter.
See also:
General notes
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