Get Occupant safety -> Purpose and function of the restraint system Guide for Mercedes CLA 4 Door Third Generation (2025-2026)

Function of the post-collision brake aer an acci-

dent

Depending on the accident situation, the post-col-

lision brake can minimise the severity of a further

collision or even avoid it.

If an accident is detected, the post-collision brake

can initiate automatic braking. When the vehicle

has come to a standstill, the electric parking

brake is automatically applied.

The driver can cancel automatic braking by taking

the following actions:

Braking more strongly than automatic braking

Fully depressing the accelerator pedal with

force

Purpose and function of the restraint system

Overview of deployment situations (restraint sys-

tem)

Make sure that the following prerequisites in par-

ticular have been met so that the components of

the restraint system are able to provide the inten-

ded level of protection:

Sit correctly (/ page 37).

Fasten the seat belt correctly (/ page 38).

Function of the seat belt warning lamp

(/ page 40).

Function of the rear seat belt status dis-

play (/ page 40).

The restraint system warning lamp 6 is not

lit up aer the self-test (/ page 39).

The PASSENGER AIR BAG indicator lamps dis-

play the correct status of the front passenger

air bag (/ page 41).

Depending on the detected deployment situation,

the components of the restraint system can be

activated or deployed independently of each

other:

Emergency Tensioning Device: frontal impact,

rear impact, side impact, rollover

Driver's air bag, front passenger air bag: fron-

tal impact

Knee air bag: frontal impact

Side impact air bag: side impact

Window curtain air bag: side impact, rollover,

frontal impact

The installation location of an air bag is identied

by the AIRBAG symbol (/ page 52).

Observe the information on the function of the

restraint system (/ page 46).

Information on how the restraint system works

How the restraint system functions depends on

the severity of the impact detected and the appa-

rent type of accident.

Occupant safety – Purpose and function of the restraint system

For more information about types of accidents,

see "Overview of deployment situations"

(/ page 46).

The activation thresholds for the components of

the restraint system are determined based on the

evaluation of the sensor values measured at vari-

ous points in the vehicle. This process is pre-emp-

tive in nature. The triggering/deployment of the

components of the restraint system must take

place in good time at the start of the collision.

Factors that can be seen and measured only aer

a collision has occurred cannot play a decisive

role in air bag deployment. Nor do they provide an

indication of air bag deployment.

The vehicle may be deformed signicantly without

an air bag being deployed. This is the case if only

parts which are relatively easily deformed are

aected and the rate of vehicle deceleration is

not high. Conversely, an air bag may be deployed

even though the vehicle suers only minor defor-

mation. If very rigid vehicle parts such as longitu-

dinal members are hit, this may result in su-

ciently high levels of vehicle deceleration.

Depending on the apparent type of accident and

the detected deployment situation, Emergency

Tensioning Devices and/or air bags can supple-

ment the protection oered by a correctly worn

seat belt.

When enabled, an air bag can provide additional

protection for the respective vehicle occupant.

Potential protection provided by each air bag:

Knee air bag: thigh, knee and lower leg

Driver's air bag, front passenger air bag: head

and ribcage

Window air bag: head

Side air bag: ribcage and pelvis

NOTE Mercedes-AMG vehicles

Observe the notes in the Supplement.

You could otherwise fail to recognize

dangers.

However, no system available today can com-

pletely eliminate injuries and fatalities in every

accident situation. In particular, the seat belt and

air bag generally do not protect against objects

penetrating the vehicle from the outside. It is also

not possible to completely rule out the risk of

injury caused by the air bag deploying.

Mercedes-Benz recommends that you have the

vehicle towed to a qualied specialist workshop

aer an accident. Take this into account, particu-

larly if an Emergency Tensioning Device is trig-

gered or an air bag deployed.

If the Emergency Tensioning Devices are triggered

or an air bag is deployed, you will hear a bang,

and a small amount of powder may also be

released:

The bang will not generally aect your hearing.

In general, the powder released is not hazard-

ous to health but may cause short-term

breathing diculties to persons suering from

asthma or other pulmonary conditions.

Provided it is safe to do so, leave the vehicle

immediately or open the window in order to

prevent breathing diculties.

Air bags and pyrotechnic Emergency Tensioning

Devices contain perchlorate material, which may

require special handling or environmental protec-

Occupant safety – Purpose and function of the restraint system

tion measures. National guidelines regarding

waste disposal must be observed. In California,

see the Using the search

function, you will nd information on perchlorate,

for example.

Information on the limited protection provided by

the restraint system

Risk due to the incorrect behavior of vehicle occu-

pants

All vehicle occupants must make sure of the fol-

lowing in particular:

They observe the information on the correct

seat position (/ page 37).

There are no heavy, sharp-edged or fragile

objects in the pockets of their clothing. Store

such objects in a suitable place.

WARNING Risk of injury or death due to

an incorrect seat position

The seat belt does not oer the intended level

of protection if you have not moved the seat

backrest to an almost vertical position.

In particular, you could slip beneath the seat-

belt and become injured.

Adjust the seat properly before begin-

ning your journey.

Always ensure that the seat backrest is

in an almost vertical position and that

the shoulder belt is routed across the

center of your shoulder.

Risk due to objects in the vehicle interior

All vehicle occupants must make sure of the fol-

lowing in particular:

They observe the information on the correct

seat position (/ page 37).

There are no objects between the seat, door

and door pillar (B-pillar).

There are no hard objects, e.g. coat hangers,

hanging on the grab handles or coat hooks.

There are no heavy, sharp-edged or fragile

objects in the pockets of their clothing. Store

such objects in a suitable place.

WARNING Risk of injury or death due to

blocked seat belt buckle or seat belt

anchorage

Objects next to the front seat that block the

seat belt buckle or the moving seat belt

anchorage on the front seat impair the func-

tion of the Emergency Tensioning Devices.

Before starting the journey, make sure

that there are no objects around the seat

belt buckle or between the front seat

and door.

WARNING Risk of injury from objects in

the deployment area of an airbag

Objects in the deployment area of an airbag

can hinder or prevent the correct deployment

of the airbag.

Occupant safety – Purpose and function of the restraint system

The airbag may then deploy in an uncontrolled

manner and may even cause additional inju-

ries to the vehicle occupants by deploying.

This may be the case in particular if the airbag

is integrated into the seat.

Always stow and secure objects cor-

rectly.

Before commencing your journey, make

sure that no objects are stowed in the

deployment area of an airbag.

The installation location of an air bag is identied

by the AIRBAG (/ page 52) symbol.

Risk due to installing accessories

Do not attach accessories such as mobile naviga-

tion devices, mobile phones or cup holders within

the deployment area of an air bag, e.g. on the

cockpit, on the door, on the side window or on the

side trim.

In addition, no connecting cables, tensioning

straps or retaining straps may be routed or

attached to the vehicle within the deployment

area of an air bag. Always comply with the acces-

sory manufacturer's installation instructions and,

in particular, the notes on suitable places for

installation.

WARNING Risk of injury or death due to

unsuitable protective covers

Unsuitable protective covers mean that air

bags can no longer protect vehicle occupants

as they are designed to do.

Use only protective covers approved by

Mercedes-Benz for the seat in question.

In addition, the function of the automatic

passenger air bag deactivation may be restricted

by an unsuitable protective cover. If the front

passenger seat is occupied, ensure that the

PASSENGER AIR BAG indicator lamps display the

correct status of the front passenger air bag

(/ page 41).

Risk due to pets in the vehicle interior

WARNING Risk of accident and injury due

to animals le unsecured or unattended in

the vehicle

If you leave animals in the vehicle unattended

or unsecured, they could possibly press but-

tons or switches.

An animal may:

Activate vehicle equipment and become

trapped, for example

Switch systems on or o and endanger

other road users

Unsecured animals may be thrown around in

the vehicle in the event of an accident or sud-

den steering and braking maneuvers and

injure vehicle occupants in the process.

Never leave animals in the vehicle unat-

tended.

Always correctly secure animals while

driving, e.g. using a suitable animal car-

rier.

Occupant safety – Purpose and function of the restraint system

Risk due to modication, damage or wear to the

components of the restraint system

NOTE Mercedes-AMG vehicles

Observe the notes in the Supplement.

You could otherwise fail to recognize

dangers.

WARNING Risk of injury or death due to

modications to the restraint system

Vehicle occupants may no longer be protected

as intended if alterations are made to the

restraint system.

Never alter the parts of the restraint sys-

tem.

Never tamper with the wiring or any elec-

tronic component parts or their so-

ware.

If it is necessary to modify the vehicle to accom-

modate a person with disabilities, contact an

authorized Mercedes-Benz Center for details.

USA only: for details, contact our Customer Assis-

tance Center on 1-800-FOR-MERCedes

(1‑800‑367‑6372).

WARNING Risk of injury or death due to

damaged or modied seat belts

Seat belts cannot provide protection in the fol-

lowing situations:

The seat belt is damaged, has been modi-

ed, is extremely dirty, bleached or dyed

The seat belt buckle is damaged or

extremely dirty

Modications have been made to the

Emergency Tensioning Device, seat belt

anchorage or seat belt retractor

Seat belts may sustain non-visible damage in

an accident, e.g. due to glass splinters.

Modied or damaged seat belts could tear or

fail in the event of an accident, for example.

Modied Emergency Tensioning Devices could

accidentally trigger or fail to function as inten-

ded.

Never modify the seat belt system, for

example the seat belt, seat belt buckle,

Emergency Tensioning Device, seat belt

anchorage and seat belt retractor.

Make sure that the seat belts are undam-

aged, not worn and clean.

Always have the seat belts checked

immediately aer an accident at a quali-

ed specialist workshop.

Use only seat belts that have been approved for

your vehicle by Mercedes-Benz.

The seat is designed for the standard three-point

seat belt. If you install a dierent multipoint seat

belt, such as a four-point seat belt, the restraint

system will not be able to provide the intended

level of protection.

Depending on the type of vehicle, there may be

openings in the seat backrest. These openings

have no function.

Occupant safety – Purpose and function of the restraint system

WARNING Risk of injury or fatal injury due

to modied seat belt systems

If you feed seat belts through the opening in

the seat backrest, the seat backrest may be

damaged or may even break in the event of an

accident.

Only use the standard three-point seat

belt.

Never modify the seat belt system.

WARNING Risk of injury due to modica-

tions to the cover of an airbag

If you change the cover of an airbag or attach

objects, e.g. even stickers, to it, the airbag

may no longer function as intended.

Never modify the cover of an airbag.

Do not attach any objects to the cover.

The installation location of an air bag is identied

by the AIRBAG symbol (/ page 52).

WARNING Risk of injury due to malfunc-

tioning sensors in the door

The function of the airbags can be impaired

due to modications or incorrect work per-

formed on the doors or door trim, or if the

doors are damaged.

Never modify the doors or parts of the

doors.

Always have work on the doors or door

trim carried out at a qualied specialist

workshop.

Risk due to components of the restraint system

that have already been deployed

Mercedes-Benz recommends that you have the

vehicle towed to a qualied specialist workshop

aer an accident.

WARNING Risk of burns from hot air bag

components

The air bag parts are hot aer an air bag has

been deployed.

Do not touch the air bag parts.

Have a deployed air bag replaced at a

qualied specialist workshop as soon as

possible.

WARNING Risk of injury due to deployed

airbag

A deployed airbag no longer oers any protec-

tion.

Have the vehicle towed to a qualied

specialist workshop in order to have the

deployed airbag replaced.

Have deployed air bags replaced immediately.

WARNING Risk of injury or death from

deployed pyrotechnic Emergency Tension-

ing Devices

Pyrotechnic Emergency Tensioning Devices

that have been deployed are no longer opera-

tional and are unable to perform their inten-

ded protective function.

Therefore, have deployed pyrotechnic

Emergency Tensioning Devices immedi-

Occupant safety – Purpose and function of the restraint system

ately replaced at a qualied specialist

workshop.

Seat belts

Releasing seat belts

Press the release button in the seat belt

buckle and guide the seat belt back with the

seat belt tongue.

NOTE Damage caused by trapping the

seat belt

If an unused seat belt is not fully retracted, it

may become trapped in the door or in the seat

mechanism.

Always ensure that an unused seat belt

is fully retracted.

Airbags

Overview of air bags

Driver's knee air bag

Driver's air bag

Front passenger air bag

Front passenger knee air bag

Window curtain air bag

Side impact air bag

The installation location of an air bag is identied

by the AIRBAG symbol.

Observe the information under "Overview of

deployment situations" (/ page 46).

Occupant safety

Occupant safety -> Purpose and function of the restraint system for Your Mercedes CLA 4 Door Third Generation (2025-2026)

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