MERCEDES-BENZ B-CLASS HATCHBACK 2021 Repair Manual

lamp is o.,
the front passenger airbag can
deploy in theev ent of an accident.
The child could be struck bythe airbag. #
Always ensu rethat the front passenger
airbag is disabled. The PASSENGER AIR
BAG OFF indicator la mpmust be lit. #
NEVER use a rear wa rd-facing child
re straint system on a seat wi than ENA-
BLED FRONT AIR BAG. This can result in
th e DEATH of or SERIOUS INJURY tothe
CHILD. When /tting a
child restraint system tothe front
passenger seat, obser vetheve hicle-speci/c infor-
mation (/ page 76).
Depending on thech ild restraint system and the
stature of thech ild, thePA SSENGER AIR BAG OFF
indicator la mpmay be o.. In this case, do not /t
th ere ar wa rd-facing child restraint system tothe
front passenger seat.
Instead, /t there ar wa rd-facing child restraint sys-
te m to a suitable rear seat.
ATer
ATer /tting /tting a f
a forw
orw ar
ard-f
d-f acing c
acing c hild r
hild res
estr
traint sy
aint sy s-
s-
t
t em t
em t o t
o the fr
he fr ont passeng
ont passeng er seat
er seat::depending on thech
ild restraint system and the stature of thech ild,
PA SSENGER AIR BAG OFF may be lit continuous ly
or be o.. Alw ays obser vethefo llowing informa-
tion. &
W
WARNING
ARNING Risk of injury or death due to
incor rect positioning of thefo rw ard-facing
ch ild restraint system
If yo u secure a child in a forw ard-facing child
re straint system on the front passenger seat
th at is positioned too close tothe cockpit, in
th eeve nt of an accident, thech ild could:
R come into contact with parts of theve hi-
cle's interior if thePA SSENGER AIR BAG
OFF indicator la mpis lit, forex ample
R be st ruck bythe airbag if thePA SSENGER
AIR BAG OFF indicator la mpis o. #
Always mo vethe front passenger seat as
fa r back as possible and fully retract the
seat cushion length adjustment. While
doing so, alw ays make sure that the
shoulder belt st rap is cor rectly routed
from the seat belt outlet of theve hicle to
th e shoulder belt guide on thech ild re
straint system. The shoulder belt strap
must be routed forw ards and down wards
from the seat belt outlet. If necessar y,
adjust the front passenger seat accord-
ingl y. #
Always comply with thech ild restraint
system manufactu rer's installation
inst ructions. When /tting a
child restraint system tothe front
passenger seat, obser vetheve hicle-speci/c infor-
mation (/ page 76).
If a per If a per son is sitting on t
son is sitting on t he fr
he front passeng
ont passeng er seat
er seat::
PA SSENGER AIR BAG OFF may be lit continuous ly
or be o., depending on the person's stature.
A person on the front passenger seat must alw ays
obser vethefo llowing information:
R Ifth e front passenger seat is occupied byan
adult or a person with a stature cor responding
to that of an adult, thePA SSENGER AIR BAG
OFF indicator la mpmust be o.. This indicates
th at the front passenger airbag is enabled.
If th ePA SSENGER AIR BAG OFF indicator
la mp is lit continuousl y,an adult or person 58
58
Occupant saf
ety

with a build cor
responding tothat of an adult
must not use the front passenger seat.
Instead, they should use a rear seat.
R Ifth e front passenger seat is occupied by a
person of smaller stature (e.g. a teenager or
small adult), thePA SSENGER AIR BAG OFF
indicator la mpis either lit continuously or
re mains o., depending on the classi/cation.
- Ifth ePA SSENGER AIR BAG OFF indicator
la mp is o.: mo vethe front passenger seat
as far back as possible, or the person of
smaller stature should use a rear seat.
- Ifth ePA SSENGER AIR BAG OFF indicator
la mp is lit continuousl y:the person of
smaller stature should not use the front
passenger seat. &
W
WARNING
ARNING Risk of injury or death when
th ePA SSENGER AIR BAG OFF indicator
la mp is lit
If th ePA SSENGER AIR BAG OFF indicator
la mp remains lit aTer the self-test, the front
passenger airbag is disabled. If
th e front passenger seat is occupied, alw ays
ensure that:
R The classi/cation of the person in the front
passenger seat is cor rect and the front
passenger airbag is enabled or disabled in
accordance with the person in the front
passenger seat.
R The person is seated proper lywith a cor-
re ctly fastened seat belt.
R The front passenger seat has been mo ved
as far back as possible. Be sure
toalso obser vethefo llowing fur ther rela-
te d subjects:
R Child restraint system on the front passenger
seat (/ page 76)
R Suitable positioning of thech ild restraint sys-
te m (/ page 66) PRE-S PRE-S
AFE
AFE®
®
syst
syst em
em F
F
unction of PRE-S
unction of PRE-S AFE
AFE®
®
(anticipat
(anticipat or
ory occupant
y occupant
pr ot
pr otection)
ection) PRE-SAFE
®
is able todetect cer tain critical driv-
ing situations and implement pre-em ptive meas-
ures toprotect theve hicle occupants.
PRE-SAFE ®
can implement thefo llowing meas-
ures independently of each other:
R Tightening the seat belts on the driver's seat
and front passenger seat.
R Closing the side windo ws.
R V
V ehicles wit
ehicles wit h sliding sunr
h sliding sunr oof:
oof:closing the slid-
ing sunroof.
R V
Vehicles wit
ehicles wit h memor
h memory function:
y function: movingthe
front passenger seat toa more favo urable seat
position.
R PRE-SAFE ®
Sound: pr ovided that the multime-
dia system is switched on, generating a brief
noise signal tostimula tethe innate pr otective
mechanism of a person's hearing. Occupant saf
ety
59
59

*
N
NO
OTE
TE Damage caused byobjects in the
fo ot we ll or behind the seat The automatic adjustment of
the seat position
may result in damage tothe seat and/or the
object. #
Stow objects in a suitable place. R
R
e
ev
ver
er sing t
sing t he PRE-S
he PRE-S AFE
AFE®
®
syst
syst em measur
em measur es
es If an accident did not occur,
the pre-em ptive
measures that we re ta ken are reve rsed.
Yo u will need toper form certain settings yourself. #
Ifth e seat belt pre-tensioning is not reduced,
mo vethe seat backrest back slightl y.
The locking mechanism releases. F
F
unction of PRE-S
unction of PRE-S AFE
AFE ®
®
PL
PL US (anticipat
US (anticipat or
ory occu-
y occu-
pant pr ot
pant pr otection plus)
ection plus) PRE-SAFE
®
PLUS can de tect cer tain impacts, par-
ticular lyan imminent rear impact, and take pre-
em ptive measures toprotect theve hicle occu- pants. These measures cann
otnecessarily pre-
ve nt an imminent impact.
PRE-SAFE ®
PLUS can implement thefo llowing
measures independently of each other:
R Tightening the seat belts on the driver's seat
and front passenger seat.
R Activating there ar hazard warning lights at a
higher 0ashing frequency.
R Increasing brake pressure when theve hicle is
stationar y.This brake application is cancelled
automatically when theve hicle pulls away.
If an accident did not occur, the pre-em ptive
measures that we re ta ken are reve rsed.
Syst
Syst em limits
em limits
The system will not initiate any action in thefo l-
lowing situations:
R when reve rsing
or
R when theve hicle is towing a trailer and there
is a risk of a rear impact The system will not initiate any braking application
in thefo llowing situations:
R whilst driving
or
R when entering or exiting a parking space while
using Active Parking Assist A A
ut
ut omatic measur
omatic measur es
esaTer
aTer an accident
an accident
Depending on the type and se verity of the acci-
dent, and depending on theve hicle's equipment,
th efo llowing measures can be implemented, for
ex ample:
R automatic braking (post-collision brake)
R activating the hazard warning lights
R triggering an automatic emer gency call
(/ page 325)
R switching o. the engine
To start theve hicle again, switch theve hicle
o. and on once more (/ page 169). Depend-
ing on the type and se verity of the accident,
yo u may no longer be able tostart theve hicle.
R switching o. the fuel supply 60
60
Occupant saf
ety

R
v
vehicles wit
ehicles wit h h
h hybr
ybr id dr
id dr iv
ive:
e: switching o. the
hy brid system and high-voltage on-board elec-
trical system
R unlocking theve hicle doors
R lowe ring the side windo ws
R displaying the emer gency guide in the multi-
media system display
R switching on the interior lighting
F
F unction of t
unction of t he pos
he post-collision brt-collision br ake
ake
Depending on the accident situation, the post-col-
lision brake can minimise the se verity of a fur ther
collision or evenavo id it.
If an accident is de tected, the post-collision brake
can implement automatic braking. When theve hi-
cle has come toa standstill, the electric parking
brake is automatically applied.
The driver can cancel automatic braking bytaking
th efo llowing actions:
R braking more strongly than automatic braking
R fully depressing the accelerator pedal with
fo rce Saf Saf
el
ely tr
y tr anspor
anspor ting c
ting childr
hildren in t
en in t he v
he vehicle
ehicle Alw
ay
Alw ays observ
s observ e when c
e when c hildr
hildren ar
en ar e trav
e tr avelling in t
elling in t he
he
v
v ehicle
ehicle %
Also strictly obser vethe saf ety no tesfo rthe
speci/c situation. In this wa yyo u can recog-
nise po tential risks and avoid dangers if chil-
dren are tr avelling in theve hicle
(/ page 62).
Be dilig
Be dilig ent
ent
Bear in mind that negligence when securing a
ch ild in thech ild restraint system ma y haveseri-
ous conse quences. Alw ays be dili gent in securing
a ch ild carefully before every journe y.
Ne ver allow babies and children totrave l sitting
on the lap of ano ther vehicle occupant.
To impr oveprotection forch ildren younger than
12 years old or under 1.50 m in height,
Mercedes-Benz recommends you obser vethefo l-
lowing information:
R Always secure thech ild in a child restraint sys-
te m suitable forth is Mercedes-Benz vehicle.
R The child restraint system must be appropria te
to the age, weight and size of thech ild. R
The vehicle seat must be suitable for /tting a
ch ild restraint system (/ page 66).
Ac cident statistics show that children secured on
th ere ar seats are generally sa ferth an children
secured on the front seats. Forth is reason,
Mercedes-Benz st rongly advises that you /t a
ch ild restraint system toare ar seat.
The g The g ener
eneric t
ic ter
erm c
m c hild r
hild r es
estr
traint syst
aint syst em
em
The generic term child restraint system is used in
th is Owner's Manual. A child restraint system is,
fo rex ample:
R a baby car seat
R are ar wa rd-facing child seat
R afo rw ard-facing child seat
R ach ild booster seat with a backrest and seat
belt guide
Mercedes-Benz recommends using a child
booster seat with a backrest.
The child restraint system must be appropria te to
th e age, weight and size of thech ild. Occupant saf
ety
61 61

Observ
Observ
e law
e laws and leg
s and leg al r
al req
equir
uir ements
ements
Alw ays obser vethe legal requ irements when
using a child restraint system in theve hicle.
Make sure that thech ild restraint system is
appro ved in accordance with theva lid test speci/-
ca tions and guidelines. Further information can
be obtained at a quali/ed specialist workshop.
Mercedes-Benz recommends that you use a
Mercedes-Benz Service Centre forth is purpose.
Onl
Onl y use appr ov
y use appr oved ced c hild r
hild r es
estrtraint syst
aint syst ems
ems
Only child restraint systems that meet thefo llo w-
ing UNECE standards are permitted for use in the
ve hicle:
R UN-R44
R UN-R129 (i-Size child restraint systems)
In fo rm ation on child restraint system appro val
categories and de tails on the appr oval label on
th ech ild restraint system (/ page 66). Det
Det
ecting r
ecting r isk
isks,av
s, avoiding dangoiding dang er
er Secur Secur
ing syst ing syst ems f
ems for c
or child r
hild r es
estrtraint syst
aint syst ems in
ems in
t
t he v
he v ehicle
ehicle
Only use thefo llowing securing systems forch ild
re straint systems:
R the ISOFIX or i-Size securing rings
R theve hicle's seat belt system
R theTo pTe ther anchorages
Fi tting an ISOFIX or an i-Size child restraint sys-
te m is prefer red.
Simply attaching tothe securing rings on theve hi-
cle can reduce therisk of /tting thech ild restraint
system incor rectl y.
When securing a child with the integ rated seat
belt of the ISOFIX or i-Size child restraint system,
al wa ys comply with the permissible gross weight
fo rth ech ild and child restraint system
(/ page 70).
A
A dv
dv ant
ant ag
age of a r
e of a r earw
earwar
ard-f
d-f acing c
acing c hild r
hild res
estrtraint sy
aint sy s-
s-
t
t em
em
It is preferable totransport a baby or a small child
in a suitable rear wa rd-facing child restraint sys- te
m. In this case, thech ild sits in the opposite
direction tothe direction of tr avel and faces bac k-
wa rds.
Babies and small children ha vecomparatively
we ak neck muscles in relation tothe size and
we ight of their head. The risk of injury tothe cer-
vical spine during an accident can be reduced in a
re ar wa rd-facing child restraint system.
Alw ay
Alw ays secur
s secur e a c
e a child r
hild r es
estr
traint syst
aint syst em corr
em correctly
ectly &
W
WARNING
ARNING Risk of injury or death due to
incor rect ins tallation of thech ild restraint
system
The child can then not be pr otected or
re strained as intended. #
Be su retocomply with the manufactur-
er's installation inst ructions forth ech ild
re straint system and its co rrect use. #
Make sure that the entire base of the
ch ild restraint system al ways rests on
th e sitting sur face of the seat. 62
62
Occupant saf
ety

#
Never place objects (e.g. cushions)
under or behind thech ild restraint sys-
te m. #
Use child restraint systems on lywith the
original co ver designed forth em. #
Alwaysre place damaged co vers with
ge nuine co vers. &
W
W ARNI NG
ARNI NGRisk of injury or dea thdue to
unsecured child restraint systems in the
ve hicle
If th ech ild restraint system is incor rectly /tted
or not secured, it can come loose.
The child restraint system could be 0ung
around and hit vehicle occupants. #
Always ins tallch ild restraint systems co r-
re ctl y,even when not in use. #
Always comply with thech ild restraint
system manufactu rer's installation
inst ructions. R
Always obser vethech ild restraint system
manufactu rer's installation and operating inst
ructions as well as theve hicle-speci/c
information:
- Fitting the ISOFIX or i-Size child restraint
system tothere ar seat (/ page 70).
- Securing thech ild restraint system wi th
th e seat belt on there ar seat
(/ page 74).
- Securing thech ild restraint system wi th
th e seat belt on the front passenger seat
(/ page 77). Obser vethe speci/c
inst ructions forth ere ar wa rd-facing and
fo rw ard-facing child restraint systems
(/ page 76).
If th e front passenger seat is occupied,
ensure, bo thbefore and during the jour-
ne y,that the status of the front passenger
airbag is cor rect forth e cur rent situation
(/ page 57).
R Obser vethewa rning labels in theve hicle inte-
ri or and on thech ild restraint system.
R Also secu reTopTe ther if present. Do no
Do no t modify t
t modify t he c
he child r
hild r es
estr traint syst
aint syst em
em &
W
WARNING
ARNING Risk of injury due tomodi/ca-
tions tothech ild restraint system
The child restraint system can no longer func-
tion prope rly. This poses an increased risk of
injur y. #
Never modify a child restraint system. #
Onlya1x accessories which ha vebeen
specially appr ovedfo rth is ch ild restraint
system bythech ild restraint system's
manufactu rer. Mercedes‑Benz
recommends Mercedes-Benz
care products for cleaning child restraint systems
re commended byMercedes-Benz. Occupant sa
fety
63
63

Onl
Onl
y use c
y use c hild r
hild res
estrtraint syst
aint syst ems whic
ems whic h ar
h are in
e in
pr
pr oper w
oper w or
orking condition
king condition &
W
WARNING
ARNING Risk of injury or death caused
by the use of damaged child restraint sys-
te ms
Child restraint systems or their reta ining sys-
te ms that ha vebeen subjected tostress in an
accident ma y not be able toper form their
intended pr otective function.
It may be the case that thech ild cannot be
proper ly restrained. #
Always immediately replace child
re straint systems that ha vebeen dam-
aged or in volved in an accident. #
Have the securing systems forth ech ild
re straint systems checked at a quali/ed
specialist workshop before ins talling a
ch ild restraint system again. A
A
v
void dir
oid dir ect sunlight
ect sunlight &
W
WARNING
ARNING Risk of bu rns when thech ild
seat is exposed todirect sunlight
If th ech ild restraint system is exposed to
direct sunlight or heat, parts could heat up.
Children could su.er burns from these parts,
particular lyon me tallic parts of thech ild
re straint system. #
Always make sure that thech ild restraint
system is not exposed todirect sunlight. #
Protect thech ild restraint system wi th a
blank et,fo rex ample. #
Ifth ech ild restraint system has been
ex posed todirect sunlight, allow it to
cool before securing a child into it. #
Never lea vechildren unattended in the
ve hicle. Observ Observ
e when st
e when st opping or par
opping or par king
king &
W
WARNING
ARNING Risk of accident and injury due
to leaving children unattended in theve hi-
cle
If ch ildren are leT unattended in theve hicle,
th ey could, in particular:
R open doors, thereby endangering other
persons or road users.
R get out and be struck byoncoming tra1c.
R operate vehicle equipment and become
trapped, forex ample.
In addition, thech ildren could also set the
ve hicle in motion by,fo rex ample:
R releasing the parking brake.
R changing the transmission position.
R starting theve hicle. #
Never lea vechildren unattended in the
ve hicle. #
When leaving theve hicle, alw aysta ke the
ke y with you and lock theve hicle. 64
64
Occupant saf
ety

#
Keep theve hicle key out of there ach of
ch ildren. &
W
W ARNING
ARNING Risk offatal injury due toexpo-
sure toextreme heat or cold in theve hicle
If persons, particular lych ildren, are subjected
to prolonged exposure tointense heat or cold,
th ere is a risk of se vere injury or even death. #
Never lea vepersons, particular lych il-
dren, unattended in theve hicle. Ov
Ov
er
ervie
vie w of r
w of r ecommended c
ecommended c hild r
hild res
estr
traint syst
aint syst ems
ems %
Further information on the cor rect child
re straint system can be ob tained at a quali-
/ed specialist workshop. Mercedes-Benz rec-
ommends that you use a Mercedes-Benz
Service Centre forth is purpose. Secur
Secur ing wit
ing wit h ISOFIX
h ISOFIX
W
W eight cat
eight cat egor
egory 0+ (up t
y 0+ (up t o 13 k
o 13 kg and up to
g and up to
appro
appro x. 15 mont
x. 15 mont hs)
hs) T
T
ype
ype 1
1
B
BAB
AB Y S
Y S AFE plus
AFE plus
Size catego ry E
Appro valE 1 04 301 146
Order number 2
B6 6 86 8224
1 Manufacturer: Britax Römer .2 With colour code 9H95. W
W
eight cat
eight cat egor
egory I (9 t
y I (9 t o 18 k
o 18 kg and fr g and fr om appro
om appro x-
x-
imat
imat el
ely 9 mont
y 9 mont hs t
hs to 4 y
o 4 y ear
ears)
s) T
T
ype
ype 1
1
DUO plus
DUO plus
Size categor yB1
Appro valE 1 04 301 133
Order number 2
A 000 970 43 02
1 Manufacturer: Britax Römer .2 With colour code 9H95. Secur
Secur
ing wit
ing wit h t
h the v
he v ehicle seat belt
ehicle seat belt
W
W eight cat
eight cat egor
egory 0 (up t
y 0 (up t o 10 k
o 10 kg and approg and appro ximat
ximat ely
ely
6 mont
6 mont hs) and w
hs) and w eight cat
eight categor
egory 0+ (up t
y 0+ (up t o 13 kg
o 13 kg
and appro
and appro ximat
ximatel
ely 15 mont
y 15 mont hs)
hs) T
T
ype
ype 1
1
B
BAB
AB Y S
Y S AFE plus II
AFE plus II
Appr oval E1 04 301 146
Order number 2
A 000 970 38 02
1 Manufactu rer: Britax Römer .2 With colour code 9H95. W
W
eight cat
eight cat egor
egory I (9 t
y I (9 t o 18 k
o 18 kg and fr g and fr om appro
om appro x-
x-
imat
imat el
ely 9 mont
y 9 mont hs t
hs to 4 y
o 4 y ear
ear s)
s) T
T
ype
ype 1
1
DUO plus
DUO plus
Appr oval E1 04 301 133
Order number 2
A 000 970 43 02
1 Manufactu rer: Britax Römer .2 With colour code 9H95. Occupant saf
ety
65
65

W
W
eight cat
eight cat egor
egory II/III (15 t
y II/III (15 t o 36 k
o 36 kg and frg and fr om
om
appro
appro ximat
ximatel
ely 3 t
y 3 t o 12 y
o 12 y ear
ears)
s) T
T
ype
ype 1
1
KIDFIX XP
KIDFIX XP
Appr oval E1 04 301 304
Order number 2
A 000 970 49 02 T
T
ype
ype 1
1
AMG KIDFIX XP
AMG KIDFIX XP
App rova lE 1 04 301 304
Order number 2
A 000 970 33 02
1 Manufacturer: Britax Römer .2 With colour code 9H95. Ov
Ov
er
ervie
vie w of suit
w of suit able seats in t
able seats in t he v
he vehicle f
ehicle f or
or/tting
/tting
a c
a c hild r
hild r es
estrtraint syst
aint syst em
em LeT/r
LeT/r
ight
ightr
rear seat
ear seat
Prefer red securing system:
® ISOFIX child seat securing system
(/ page 68)
or °
i-Sizechild seat securing system
(/ page 69)
¯ Also secure TopTe ther if present
(/ page 72).
Alternative securing system:
0076 Vehicle seat belt (/ page 73)
F
F r
r ont passeng ont passeng er seat
er seat
Securing system:
0076 Vehicle seat belt (/ page 73)
Be sure toobser ve:
R Ifth e front passenger seat is occupied,
ensure, bo thbefore and during the journe y,
th at the status of the front passenger airbag is
cor rect forth e cur rent situation (/ page 57).
R Notes on automatic front passen ger airbag
shuto. (/ page 55).
Centr Centr e r e rear seat
ear seat
Securing system:
0076 Vehicle seat belt (/ page 73) App
rov
Approv al cat
al categor
egor ies f
ies f or c
or child r
hild r es
estrtraint syst
aint syst ems
ems Onl Onl
y use app rov
y use appr oved ced c hild r hild r es
estrtraint syst
aint syst ems
ems
Only child restraint systems that meet thefo llo w-
ing UNECE standards are permitted for use in the
ve hicle:
R UN-R44
R UN-R129 (i-Size child restraint systems)
Iden ti/cation
Identi/cation on t
on the c
he c hild r
hild r es
estr
traint sy st
aint syst em
em
In fo rm ation about the appr oval catego ry,we ight
category and appr oval number, forex ample, is on
th e appr oval label on thech ild restraint system.
There ma y be further information such as the ISO-
FIX size categories, depending on the appr oval
catego ryofthech ild restraint system. 66
66
Occupant sa
fety

Approv
Approv
al cat
al categor
egories in accor
ies in accor dance wit
dance with UN-R44
h UN-R44 Example of an app
rova l label
R U
Univniv er
er sal:
sal: child restraint systems in the "Uni-
ve rsal" catego ryare appr ovedfo r installation
in vehicles. They can be used, in accordance
with overviews ofthe suitability of seats for
securing child restraint systems, on seats
labelled U, UF or IU F. The identi/ca
tion IUFrefers to ISOFIX child
re straint systems in the "Universal" categor y.
These child restraint systems must also be
secu red using TopTe ther or support points.
R Semi-U
Semi-U niv
niver
ersal:
sal: child restraint systems in the
"Semi-Universal" category may only be used if
th eve hicle and vehicle seat are listed in the
ch ild restraint system manufactu rer's vehicle
model list.
R V Vehicle-speci/c: ehicle-speci/c: child restraint systems in the
"vehicle-speci/c" category may only be used if
th eve hicle and vehicle seat are lis ted in the
ch ild restraint system manufactu rer's vehicle
model list. App
rov
Approv al cat al categor
egories in accor
ies in accor dance wit
dance with UN-R129
h UN-R129 Example of an app
rova l label
R i‑Size:
i‑Size: child restraint systems in the "i‑Size"
category are appr ovedfo r installation in vehi-
cles with i‑Size mounting brac kets. They can
be used, in accordance with overviews ofthe
suitability of seats for securing child restraint
systems, on seats labelled i‑ U. Occupant saf
ety
67
67