MERCEDES-BENZ B-CLASS HATCHBACK 2022 Workshop Manual

Restraint system functionality
When the vehicle is switched on, a self-test is per-
f
ormed, during which the 6 restraint system
warning lamp lights up. It goes out no later than a
few seconds aser the vehicle is started. The com-
ponents of the restraint system are then func-
tional. Malfunctioning restraint system
A malfunction has occurred in the restraint sys-
t

em if:
= the 6 restraint system warning lamp does
not light up when the vehicle is switched on
= the 6 restraint system warning lamp lights
up continuously or repeatedly during a journey
All vehicles, except plug-in hybrid: &
WARNING Risk of injur
y due to malfunc-
tions in the restraint system
Components in the restraint system may be
activ
ated unintentionally or not deploy as
intended in an accident. 
Have the restraint system checked and
r

epaired immediately at a qualiNed spe-
cialist workshop. Plug-in hybrid:
&
DANGER Risk of f
atal injuries due to
restraint system malfunctions
Components in the restraint system may be
activ
ated unintentionally or not deploy as plan-
ned in an accident. In the event of an acci-
dent, the high-voltage on-board electrical sys-
tem may not be deactivated as intended.
You may suMer an electric shock if you touch
the damaged components of the high-voltage
on-board electrical system. 
Have the restraint system checked and
r

epaired immediately at a qualiNed spe-
cialist workshop. 
Aser an accident, switc
h oM the vehicle
immediately. Function of the restraint system in an accident
How the restraint system works depends on the
se

verity of the impact detected and the apparent
type of accident:
= Frontal impact
= Rear impact
= Side impact
= Only for certain countries: rollover
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 which can only be seen and measured
aser a collision has occurred cannot play a deci-
sive role in airbag deployment. Nor do they pro-
vide an indication of airbag deployment.
The vehicle may be deformed signiNcantly without
an airbag being deployed. This is the case if only
parts which are relatively easily deformed are
aMected and the rate of vehicle deceleration is 48
Occupant safety

not high. Conversely, an airbag may be deployed
e
ven though the vehicle suMers only minor defor-
mation. If very rigid vehicle parts such as longitu-
dinal members are hit, this may result in suP-
ciently high levels of vehicle deceleration.
Depending on the detected deployment situation,
the components of the restraint system can be
activated or deployed independently of each
other:
= Seat belt tensioner: frontal impact, rear
impact, side impact, rollover 1
= Driver's airbag, front passenger airbag: frontal
impact
= Knee airbag: frontal impact
= Side airbag: side impact
= Window airbag: side impact, rollover 1
, frontal
impact
1) Only for certain countries.
Only when the PASSENGER AIR BAG OFF indica-
tor lamp is oM can the front passenger airbag
deploy in the event of an accident. If the front
passenger seat is occupied, make sure, both
before and during the journey, that the status of the front passenger airbag is correct
(
 pag
e 58). &
WARNING Risk of bur
ns from hot airbag
components
The airbag parts are hot aser an airbag has
been deplo
yed. 
Do not touch the airbag parts. 
Have a deployed airbag replaced at a
q
ualiNed specialist workshop as soon as
possible. Mercedes-Benz recommends that you have the
v

ehicle towed to a qualiNed specialist workshop
aser an accident. Take this into account, particu-
larly if a seat belt tensioner is triggered or an air-
bag deployed.
If the seat belt tensioners are triggered or an air-
bag is deplo
yed, you will hear a bang, and a small
amount of powder may also be released:
= The bang will not generally aMect your hearing.
= In general, the powder released is not hazard-
ous to health but may cause short-term breathing diPculties
t
o persons suMering 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 diPculties. Seat belts
Protection provided by the seat belt
Always fasten your seat belt correctly before
s

tarting a journey. A seat belt can only provide
the best level of protection if it is worn correctly. &
WARNING Risk of injur
y or death due to
incorrectly fastened seat belt
If the seat belt is not worn correctly, it cannot
per
form its intended protective function.
In addition, an incorrectly fastened seat belt
can also cause injuries, for example, in the
event of an accident or when braking or
changing direction suddenly. Occupant safety
49


Always ensure that all vehicle occupants
ha
ve their seat belts fastened correctly
and are sitting properly. Always observe the instructions about the correct
dr

iver's seat position and adjusting the seat
(  page 107).
In order for the correctly worn seat belt to provide
the intended level of protection, each vehicle
occupant must observe the following information:
= The seat belt must not be twisted and must Nt
tightly and snugly across the body.
= The seat belt must be routed across the
centre of the shoulder and as low down across
the hips as possible.
= The shoulder section of the seat belt should
not touch your neck nor be routed under your
arm or behind your back.
= Avoid wearing bulky clothing, e.g. a winter
coat.
= Push the lap belt down as far as possible
across your hips and pull tight with the shoul-
der section of the belt. Never route the lap
belt across your abdomen. Pregnant women must also take particular
car

e with this.
= Never route the seat belt across sharp, poin-
ted, abrasive or fragile objects.
= Only one person should use each seat belt at
any one time.
= Never secure objects with a seat belt if the
seat belt is also being used by one of the vehi-
cle's occupants.
Also ensure that no objects, e.g. a cushion,
are ever placed between a person and the
seat.
If children are travelling in the vehicle, be sure to
observe the instructions and safety notes on
"Children in the vehicle" ( page 63).
Always observe the instructions for loading the
vehicle when securing objects, luggage or loads
( page 122). Limitations of the protection provided by the seat
belt
&
WARNING Risk of injur
y or death due to
incorrect seat position
The seat belt will not oMer t
he intended level
of protection if you have not moved the seat
backrest to an almost vertical position.
In particular, you may slip under the seatbelt
and injure yourself. 
Adjust the seat properly before begin-
ning y

our journey. 
Always ensure that the seat backrest is
in an almos

t vertical position and that
the shoulder section of your seat belt is
routed across the centre of your shoul-
der. 50
Occupant safety

&
WARNING Risk of injur y or death when
additional restraint systems are not used
for persons with a smaller stature
Persons under 1.50 m tall cannot wear the
seat belt cor
rectly without a suitable addi-
tional restraint system. 
Always secure persons under 1.50 m tall
in a suit
able restraint system. &
WARNING Risk of injur
y or death due to
damaged or modiNed seat belts
Seat belts cannot provide protection in the fol-
lo
wing situations:
= the seat belt is damaged, has been modi-
Ned, is extremely dirty, bleached or dyed
= the seat belt buckle is damaged or
extremely dirty
= modiNcations have been made to the seat
belt tensioner, seat belt anchorage or seat
belt retractor
Seat belts may sustain non-visible damage in
an accident, e.g. due to glass splinters. ModiNed
or damag
ed seat belts could tear or
fail in the event of an accident, for example.
ModiNed seat belt tensioners could acciden-
tally trigger or fail to function as intended. 
Never modify the seat belt system, for
e

xample the seat belt, seat belt buckle,
seat belt tensioner, seat belt anchorage
and seat belt retractor. 
Make sure that the seat belts are undam-
ag

ed, not worn and clean. 
Always have the seat belts checked
immediat
ely aser an accident at a quali-
Ned specialist workshop. Mercedes-Benz recommends that you use seat
belts whic

h have been approved for your vehicle
by Mercedes-Benz. &
WARNING Risk of injur
y or death from
deployed pyrotechnic seat belt tensioners
Pyrotechnic seat belt tensioners that have
been deplo
yed are no longer operational and
are unable to perform their intended protec-
tive function. 
Therefore, have deployed pyrotechnic
seat belt t

ensioners immediately
replaced at a qualiNed specialist work-
shop. Mercedes-Benz recommends that you have the
v

ehicle towed to a qualiNed specialist workshop
aser an accident.
* NOTE Damag
e caused by trapping the
seat belt If an unused seat belt is not fully retracted, it
ma

y become trapped in the door or in the seat
mechanism. 
Always ensure that an unused seat belt
is full

y retracted. Fastening seat belts
If the seat belt is pulled quickly or sharply, the
seat belt r
etractor locks. The seat belt strap can-
not be pulled out any further. Occupant safety
51


Always engage seat belt tongue 2 of t he seat
belt into seat belt buckle 1 of the corre-
sponding seat.
% A seat belt can only provide the best level of
pr
otection if it is worn correctly. Observe the
notes on fastening the seat belt (  page 49).*
NOTE Deplo
yment of components of the
restraint system when the front passenger
seat is unoccupied and a seat belt is
buckled When the front passenger seat is unoccupied
and t
he seat belt tongue of the seat belt is
engaged in the seat belt buckle, components
of the restraint system may deploy unnecessa-
rily on the front passenger side, e.g. the seat
belt tensioner. 
Only buckle the seat belts as intended. %
Observe the notes on stowage areas
( pag

e 122).
Information on Ntting a child restraint system
and on children travelling in the vehicle can
be found in the "Children in the vehicle" sec-
tion ( page 67). Seat belt adjustment function
Vehicles with PRE-SAFE
n
: aser a fr
ont seat belt
has been fastened, the automatic seat belt adjust- ment may apply a certain tightening force. Do not
hold t

he seat belt tightly while it is adjusting.
You can activate and deactivate the seat belt
adjustment function using the multimedia system
(  page 52). Activating/deactivating seat belt adjustment via
t
he multimedia system Multimedia system:
4 © 5
Settings 5
Vehicle 
Activate or deactivate Belt adjustment. Releasing seat belts

Press the release button in the seat belt
buc
kle and guide the seat belt back with the
seat belt tongue. Seat belt warning function for the driver and front
passeng
er The

In addition, a warning tone may sound.
As soon as t
he driver and front passenger fasten
their seat belts, the seat belt warning goes out. Function of the rear seat belt status display
The rear seat belt status display is only available
f

or certain countries. When the vehicle is switched on, the rear seat
belt s

tatus display informs you for a certain
amount of time which rear seat belt is not fas-
tened. You can immediately dismiss the rear seat belt
s

tatus display using the back button on the les-
hand side of the steering wheel ( page 288).
If a vehicle occupant unfastens a seat belt in the
rear while the vehicle is motion, the rear seat belt
status display appears again.
In addition, a warning tone may sound. In this
case, the rear seat belt status display cannot be
hidden using the back button on the les-hand side
of the steering wheel. Airbags
Overview of airbags
1
Knee airbag
2 Driver's airbag
3 Front passenger airbag
4 Window airbag
5 Side airbag
The installation location of an airbag is identiNed
b
y the AIRBAG symbol.
When enabled, an airbag can provide additional
protection for the respective vehicle occupant. Occupant safety
53

Potential protection provided by each airbag:
= Knee airbag: t
high, knee and lower leg
= Driver's airbag, front passenger airbag: head
and ribcage
= Window airbag: head
= Side airbag: ribcage and pelvis &
WARNING Risk of injur
y or death if the co-
driver airbag is enabled
If the co-driver airbag is enabled, a child on
t
he co-driver seat may be struck by the co-
driver airbag during an accident.
NEVER use a rearward-facing child restraint
system on a seat with an ENABLED FRONT
AIRBAG; DEATH or SERIOUS INJURY to the
CHILD can occur. When
Ntting a c
hild restraint system to the front
passenger seat, observe the vehicle-speciNc infor-
mation ( page 78). Also, always observe the
notes on rearward-facing or forward-facing child
restraint systems on the front passenger seat
(  page 77). Information on automatic front passenger airbag
shut
oM
The front passenger airbag can only be deployed
in an accident if the PASSENGER AIR BAG OFF
indicator lamp is oM. If the front passenger seat is
occupied, make sure, both before and during the
journey, that the status of the front passenger air-
bag is correct ( page 58).
* NOTE Deplo
yment of components of the
restraint system when the front passenger
seat is unoccupied In an accident, the components of the
r
estraint system may deploy unnecessarily on
the front passenger side if:
= There are heavy objects on the front
passenger seat.
= The seat belt tongue is engaged in the seat
belt buckle of the front passenger seat and
the front passenger seat is unoccupied. 
Stow objects in a suitable place. 
Only one person should use each seat
belt at an
y one time. Depending on the detected accident situation, the
windo
w airbag on the front passenger side may
deploy. The airbag is deployed regardless of
whether the front passenger seat is occupied. Protection provided by the airbags
Depending on the accident situation, an airbag
ma
y supplement the protection oMered by a cor-
rectly fastened seat belt. &
WARNING Risk of injur
y or death due to
an incorrect seat position
If you deviate from the correct seat position,
t
he airbag cannot perform its intended protec-
tive function.
Each vehicle occupant must make sure of the
following:
= Fasten seat belts correctly. Pregnant
women must take particular care to ensure
that the lap belt never lies across the
abdomen. 54
Occupant safety

=
A dopt the correct seat position and keep
as far away as possible from the airbags.
= Observe the following information. 
Always make sure that there are no
objects be
tween the airbag and vehicle
occupant. To avoid the risks resulting from the deployment
of an airbag, eac

h vehicle occupant must observe
the following information in particular:
= Before starting your journey, adjust your seat
correctly; the driver's seat and front
passenger seat should be moved as far back
as possible.
When doing so, always observe the informa-
tion on the correct driver's seat position
( page 107).
= Only hold the steering wheel by the steering
wheel rim. This allows the airbag to be fully
deployed.
= Always lean against the seat backrest when
the vehicle is in motion. Do not lean forwards
or against the door or side window. You may otherwise be in the deployment area of the
airbags.
= The occupants mus

t always keep their feet on
the Ooor. Do not put your feet on the cockpit,
for example. Your feet may otherwise be in the
deployment area of the airbag.
= If children are travelling in the vehicle, observe
the additional notes ( page 63).
= Always stow and secure objects correctly.
Objects in the vehicle interior may prevent an air-
bag from functioning correctly. Each vehicle occu-
pant must always make sure of the following in
particular:
= There are no people, animals or objects
between the vehicle occupants and an airbag.
= 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 accessories, such as mobile navi-
gation devices, mobile phones or cup holders,
within the deployment area of an airbag, e.g. on the cockpit, on the door, on the side win-
do
w or on the side trim.
In addition, no connecting cables, tensioning
straps or retaining straps must be routed or
attached to the vehicle within the deployment
area of an airbag. Always comply with the
accessory manufacturer's installation instruc-
tions and, in particular, the notes on suitable
places for installation.
= There are no heavy, sharp-edged or fragile
objects in the pockets of your clothing. Store
such objects in a suitable place. Limitations of the protection provided by airbags
&
WARNING Risk of injur
y due to modiNca-
tions to the cover of an airbag
If you modify the cover of an airbag or aPx
objects suc
h as stickers to it, the airbag can
no longer function as intended. 
Never modify the cover of an airbag. 
Do not attach any objects to the cover. Occupant safety
55

The installation location of an airbag is
identiNed
b y the AIRBAG symbol ( page 53).
Objects in the deployment area of an airbag may
prevent the airbag from functioning correctly. &
WARNING Risk of injur
y from objects in
the deployment area of an airbag
Objects in the deployment area of an airbag
can hinder or pr
event the correct deployment
of the airbag.
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-
r
ectly. 
Before commencing your journey, make
sur

e that no objects are stowed in the
deployment area of an airbag. &
WARNING Risk of injur
y or death due to
the use of unsuitable seat covers
Due to unsuitable seat covers, the airbags
canno
t protect vehicle occupants as intended.
In addition, the operation of the automatic
front passenger airbag shutoM could be
restricted. 
You should only use seat covers that
ha

ve been approved for the correspond-
ing seats by Mercedes-Benz. &
WARNING Risk of injur
y due to malfunc-
tioning sensors in the door
The function of the airbags can be impaired
due t
o modiNcations 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
door

s. 
Always have work on the doors or door
tr

im carried out at a qualiNed specialist
workshop. &
WARNING Risk of injur
y due to deployed
airbag
A deployed airbag no longer oMer
s any protec-
tion. 
Have the vehicle towed to a q
ualiNed
specialist workshop in order to have the
deployed airbag replaced. Have deployed airbags replaced immediately.
Status of the front passenger front airbag
Function of the automatic front passenger airbag
shut

oM
The automatic front passenger airbag shutoM is
able to detect whether the front passenger seat is
occupied by a person or a child restraint system.
The front passenger airbag is enabled or disabled
accordingly. 56
Occupant safety

&
WARNING Risk of injur y or death due to
objects under the co-driver seat
Objects trapped under the co-driver seat can
int
erfere with the function of the automatic
co-driver airbag shutoM or damage the system. 
Do not store any objects under the co-
dr
iver seat. 
When the co-driver seat is occupied,
mak
e sure that no objects are trapped
under the co-driver seat. When Ntting
a c
hild restraint system to the front
passenger seat, observe the vehicle-speciNc infor-
mation (  page 78). Also, always observe the
notes on rearward-facing or forward-facing child
restraint systems on the front passenger seat
(  page 77).
A person on the front passenger seat must
observe the following information:
= Fasten seat belts correctly ( page 49).
= Sit in an almost upright seat position with their
back against the seat backrest. =
Sit wit
h their feet resting on the Ooor, if possi-
ble.
The front passenger airbag may otherwise be dis-
abled by mistake, for example, in the following sit-
uations:
= The front passenger transfers their weight by
supporting themselves on a vehicle armrest.
= The front passenger sits in such a way that
their weight is raised from the seat surface. &
WARNING Risk of injur
y or death due to a
disabled front passenger airbag
The front passenger airbag is disabled when
t
he PASSENGER AIR BAG OFF indicator lamp
is lit.
A person in the front passenger seat could
then, for example, come into contact with the
vehicle interior, especially if the person is sit-
ting too close to the cockpit. If the front passenger seat is occupied, always
ensur
e that:
= the classiNcation of the person in the front
passenger seat is correct and the front
passenger airbag is enabled or disabled in
accordance with the person in the front
passenger seat.
= the front passenger seat has been moved
as far back as possible.
= the person is seated correctly. 
Both before and during the journey,
ensur

e that the status of the front
passenger airbag is correct. If the front passenger seat is occupied, the classi-
Ncation
of t

he person or child restraint system on
the front passenger seat takes place aser the
front passenger airbag shutoM self-test. The
PASSENGER AIR BAG indicator lamps display the
status of the front passenger airbag.
Always observe the notes on the function of the
PASSENGER AIR BAG indicator lamps
(  page 58). Occupant safety
57