Occupant Classification System (OCS)

Method of operation

WARNING

If the 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
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 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 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 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 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 front passenger seat occupant is classified as an adult or someone larger than a small individual, the 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 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 • if the impact exceeds a predetermined triggering threshold
• 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
• the rate of vehicle deceleration as assessed by the air bag control unit • the front passenger's weight category as identified by the OCS

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 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 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 ndicator lamp is illuminated,
indicating that the front-passenger 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 that 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 the typical 12- month-old child, the front-passenger front air bag may or may not be activated.

WARNING

If the red SRS warning lamp in
the instrument cluster and the
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:
• 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.

If the SmartKey has been removed from the ignition lock or is in position 0, indicator lamp 1 does not light
up.

The Occupant Classification System (OCS) categorizes the occupant on the frontpassenger seat using a weight sensor. The front-passenger front air bag is deactivated automatically for certain weight categories.

indicator lamp 1 shows you the
current status. If indicator lamp 1 lights up, the
front-passenger air bag is disabled.

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

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
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  .

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: • is empty or occupied by the weight of a typical child up to twelve months old, seated in a child restraint system • is occupied by a small individual, such as a young teenager or a small adult • 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.

System self-test

WARNING

If the 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.

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 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 indicator lamp lights up:
• if you turn the SmartKey in the ignition lock to position 1 or 2
• if you press the KEYLESS-GO Start/Stop button once or twice on vehicles with KEYLESS-GO
• if an adult is seated properly on the frontpassenger seat and the OCS classifies the occupant as an adult
The 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 indicator lamp will
continue to light up. The
indicator lamp will not go out.

For more information about the OCS, see "Problems with the Occupant Classification System"  .

Problems with the occupant classification system

WARNING

If the indicator lamp
illuminates and remains illuminated when the weight of a typical adult or someone larger than a small individual has been detected on the passenger seat, do not allow any occupant to use the passenger seat until the system has been repaired.

WARNING

If the indicator lamp does not
illuminate or remains out with the weight of a typical 12-month-old child in a standard child restraint or less, or is unoccupied, on the front-passenger seat, do not transport a child on the front-passenger seat until the system has been repaired.