light MERCEDES-BENZ B-CLASS HATCHBACK 2021 User Guide

*
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

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

F
F
itting t
itting t he ISOFIX or i‑Size c
he ISOFIX or i‑Size c hild r
hild res
estrtraint syst
aint syst em
em
on t
on t he
heleT
leT and r
and r ight r
ight r ear seats
ear seats &
W
WARNING
ARNING Risk of accident if there ar
ben chseat, rear seat and seat backrest
are not engaged
The rear ben chseat, rear seat and seat bac k-
re st ma yfo ld forw ards, even while theve hicle
is in motion.
R As a result, theve hicle occupant will be
pressed into the seat belt with increased
fo rc e. The seat belt will not be able topro-
te ct as intended and could cause addi-
tional injur y.
R Objects or loads in the boot or load com-
partment cannot be restrained bythe seat
backrest. #
Make sure that there ar ben chseat, the
re ar seat and the seat backrest are
engaged before every trip. If
th ere ar seat backrest is not engaged and
loc ked in place, there d lock veri/cation indicator
will be visible. &
W
WARNING
ARNING Risk of inju ryor death if the
permissible gross mass of thech ild and
ch ild restraint system toge ther is excee-
ded.
To o much load may be placed on the ISOFIX
or i‑Size child restraint systems and thech ild
may not be restrained co rrectly in theev ent of
an accident, forex ample. #
Ifth ech ild and thech ild restraint system
to get her weigh more than 33 kg, only
use an ISOFIX or i‑Size child restraint
system wi thwhich thech ild is secured
with theve hicle seat belt. #
Also secure thech ild restraint system
wi th th eTo pTe ther belt, if available. Alw
ays comply with the information about the
mass of thech ild restraint system:
R inthe manufacturer's installation and operat-
ing inst ructions forth ech ild restraint system
used
R on a label on thech ild restraint system, if
present Re
gula rly ch eck that the permissible gross mass
of thech ild and child restraint system is still com-
plied wi th.
When /tting a child restraint system, obse rvethe
fo llowing:
0073 Always obser vethe cor rect use of the seats
and consider their suitability for attaching a
ch ild restraint system.
ISOFIX child seat securing system
(/ page 68)
or
i‑Size child seat securing system
(/ page 69)
0073 Always comply with the manufacturer's
installation and operating instructions forthe
ch ild restraint system used.
0073 Makesure that thech ild's feet do not touch
th e front seat. If necessar y,mo vethe front
seat slightly forw ards.
® When /tting an ISOFIX child restraint sys-
te m, also obser vethefo llowing:
0073 When using a bab
When using a bab y car seat in w y car seat in weightgr
eight group
oup
0/0+ and a r
0/0+ and a r earw
earwar
ard-f
d-f acing c
acing c hild r
hild res
estrtraint
aint 70
70
Occupant saf
ety

te
ct as intended and could cause addi-
tional injur y.
R Objects or loads in the boot or load com-
partment cannot be restrained bythe seat
backrest. #
Make sure that there ar ben chseat, the
re ar seat and the seat backrest are
engaged before every trip. If
th ere ar seat backrest is not engaged and
loc ked in place, there d lock veri/cation indicator
will be visible.
When
When /tting /tting a belt-secur
a belt-secur ed c
ed child r
hild r es
estr
traint sy st
aint syst em,
em,
obse rv
observ e t
e the f
he f ollo
ollowing:
wing:
0073 Always comply with the manufacturer's
installation and operating inst ructions forthe
ch ild restraint system used.
0073 For a child restraint system in the "Universal"
or "Semi-Universal" categor y,make sure that
th e system has been appr ovedfo rth eve hicle
seat. Obser
vethe no tes under "Suitability of seats
fo r attaching belt-secured child restraint sys-
te ms" (/ page 73).
0073 When using a w
When using a w eight cat
eight categor
egory 0/0+ bab
y 0/0+ bab y
y
car seat and a w
car seat and a w eight cat
eight categor
egory I r
y I rearw
earw ar
ard-
d-
f
f acing c
acing c hild r
hild res
estrtraint syst
aint syst em on a r
em on a r ear seat:
ear seat:
adjust the front seat so that the seat does
not touch thech ild restraint system.
0073 When using a w
When using a w eight cat
eight categor
egory I f
y I forw
orw ar
ar d-
d-
f
f acing c
acing c hild r
hild res
estr
traint sy st
aint syst em:
em:remo vethe
head restraint from there specti veseat, if
possible.
ATer thech ild restraint system has been
re mo ved, replace the head restraint immedi-
atel y and adjust all head restraints co rrectl y.
0073 The backrest of thefo rw ard-facing child
re straint system must, as far as possible, be
re sting on the seat backrest of there ar seat.
0073 Ifth e head restraint of thech ild seat cannot
be fully extended when it is installed in the
ve hicle, this will result in restrictions on the
maximum size setting forch ild restraint sys-
te ms in weight category II or III. Contact with
thero of when the head
re straint is ful lyex tended and loc ked in place
will not result in any restrictions on use.
0073 Thechild restraint system must not be put
under strain between thero of and the seat
cushion and/or be /t tedfacing the wrong
direction. Where possible, adjust the seat
cushion inclination accordingl y.
0073 Thechild restraint system must not be put
under strain bythe head restraint. Adjust the
head restraints as appropria te.
0073 Make sure that thech ild's feet do not touch
th e front seat. If necessar y,mo vethe front
seat slightly forw ards. #
Installth ech ild restraint system.
The entire base of thech ild restraint system
must al ways rest on the seat sur face of the
re ar seat. #
Always make sure that the shoulder belt strap
is cor rectly routed from the seat belt outlet of
th eve hicle tothe shoulder belt guide on the
ch ild restraint system.
The shoulder belt strap must be routed
fo rw ard from the seat belt outlet. Occupant saf
ety
75 75

K
K
e
ey
y Ov
Ov
er
ervie
vie w of ke
w of key functions
y functions &
W
W ARNING
ARNING Risk of accident and inju rydue
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. #
Keep theve hicle key out of there ach of
ch ildren. *
N
NOOTE
TE Damage totheke y caused bymag-
netic /elds #
Keep theke yaw ay from strong magnetic
/elds. Ve
hicle key
1 Locks
2 Indicator lamp 3
Unloc ks
4 Opens/closes theta ilgate
% If indicator lamp 2does not light up aTer
pressing theÜ orß button, the battery
is we ak or possibly dischar ged. Re place the
battery as soon as possible.
Re place theke y battery (/ page 83).
The key loc ksand unloc ksthefo llowing compo-
nents:
R Doors
R Fuel /ller 0ap
R Soc ket 0ap (plug-in hybrid)
R Tailgate
If th eve hicle is not opened within appr oximately
40 seconds aTer unlocking, it loc ksagain. Anti-
th eT pr otection is primed again.
Do not keep theke yto get her with elect ronic devi-
ces or me tal objects. This can a.ect theke y's
functionalit y. Opening and closing
81 81

A
A
ctiv
ctiv ating/deactiv
ating/deactiv ating t
ating the acous
he acous tic loc
tic locking
kingv
ver
er i/-
i/-
cation
cation signal
signal Multimedia system:
4 © 5
Settings 5
Vehicle #
Activate or deactivate Acoustic lock.
% Please observ
Please observ e:
e:
The selected setting forth e acoustic locking
ve ri/cation signal must comply with there le-
va nt national road and tra1c regulations. In
some countries, including German y,using the
acoustic locking veri/cation signal is forbid-
den bytra1c la ws(in accordance with §16
Pa ra. 1 and §30 Para. 1 of the German
national road tra1c regulations). The driver of
th eve hicle must comply with these regula-
tions. In countries where the use of this func-
tion is forbidden, this function is not activated
in theve hicle and must not be activated. Changing t
Changing t
he unloc
he unlocking se
king settings
ttings Po
ssible unlocking functions of theke y:
R Central unlocking
R Unlocking the driver's door and fuel /ller 0ap R
Plug-in h Plug-in h ybr ybrid:
id:unlocking the driver's door and
fuel /ller 0ap/soc ket0 ap #
T
T o switc
o switc h be
h betw
tween se
een se ttings:
ttings: presstheÜ
and ß buttons simultaneously for appr ox-
imately six seconds until the indicator lamp
0ashes twice.
Options if the unlocking function forth e driver's
door and fuel /ller 0ap has been selected:
R T To unloc o unloc k t
k the v
he v ehicle centr
ehicle centr ally:
all y: press the
Ü button twice.
R V
Vehicles wit
ehicles wit h KEYLESS-GO:
h KEYLESS-GO: ifyo uto uch the
inner sur face of the door handle on the driv-
er's door, only the driver's door and the fuel
/ller 0ap are unloc ked.
Options if the unlocking function forth e driver's
door and fuel /ller 0ap/soc ket0 ap has been
selected (plug-in-hybrid):
R T
To unloc
o unloc k t
k the v
he v ehicle centr
ehicle centr ally:
all y: press the
Ü button twice.
R V
V ehicles wit
ehicles wit h KEYLESS-GO:
h KEYLESS-GO: ifyo uto uch the
inner sur face of the door handle on the driv-
er's door, only the driver's door and the fuel
/ller 0ap/soc ket0 ap are unloc ked. Deactiv
Deactiv
ating t
ating the function of t
he function of t hekey
he key V
V
ehicles wit
ehicles wit h KEYLESS-GO:
h KEYLESS-GO: ifyo u deactivate the
function of theke y,the KEYLESS-GO functions are
also deactivated. Access or drive authorization by
KEYLESS-GO is then no longer possible with that
particular key.Activate the function of theke y so
th at all its functions will again be available.
Yo u can also deactivate the function of theke yto
re duce the energy consum ption of theke y if you
do not use theve hicle or a keyfo r an extended
period of time. #
T
To deactiv
o deactiv at
ate:
e: press theß button on the
ke y twice in quick succession.
The key indicator lamp 0ashes twice brie0y
and lights up once. #
T
To activ
o activ at
ate:
e: press any but ton on thekey.
% When theve hicle is star ted with theke y in the
st ow age compartment of the centre console,
th e function of theke y is automatical lyactiva-
te d (/ page 170). 82
82
Opening and closing

R
R
emo
emo ving/inser
ving/inser ting t
ting the emerg
he emerg encykey
ency key R R
emo emo ving t
ving t he emerg
he emerg encykey
ency key #
Press release button 1.
Emer gency key2 is pushed out slightl y.#
Pull out eme rgency key2 until it en gage s in
th e intermediate position. #
Press release button 1again and fully
re mo veemer gency key2.
Inser
Inser ting t
ting t he emerg
he emerg encykey
ency key #
Press release button 1. #
Insert emer gency key2 tothe intermediate
position or fully until it engages. %
You can use the intermediate position of
emer gency key2 toattach theke yto akey
ri ng. R
R
eplacing t
eplacing t heke
he key batt
y batt ery
ery &
D
DAN
AN GER
GER Risk of fatal injuries due toswal-
lowing batteries
Bat teries contain toxic and cor rosive subs tan-
ces. Swall owing batteries may cause se vere
internal burns tooccur within two hours.
There is a risk of fatal injur y. #
Keep batteries out of there ach of chil-
dren. #
Ifth e cap and/or the battery compart-
ment does not close securel y,do not use
th eke y any lon ger and keep it out of the
re ach of children. #
If batteries are swallo wed, seek medical
attention immediatel y. +
ENVIR
ENVIR ONMENT
ONMENT AL NO
AL NOTE
TEEnvironmen tal
damage due toimproper disposal of bat-
te ries Batteries contain pollutants. It is
illegal todispose of them with the household
ru bbish. #
Dispose of batteries in an
environmentally responsible manner.
Ta ke dischar ged batteries toaqu ali/ed
specialist workshop or toa collection
point for used batteries. R
R
eq
eq uir
uir ements:
ements:
R Youre qu ire a CR 2032 3 V cell batter y.
Mercedes-Benz recommends that you ha vethe
battery replaced at a quali/ed specialist work-
shop. #
Remo vethe emer gency key (/ page 83). Opening and closing
83
83

&
W
W ARNI NG
ARNI NGRisk of injury topersons inside
th eve hicle when the additional door lock
is activated
If th e additional door lock is activated, the
doors can no longer be opened from the
inside. #
Never lea vepersons, in particular chil-
dren, unattended in theve hicle. #
Ifth ere are persons in theve hicle, do not
activate the additional door loc k.The additional door lock is automatically activated
in
thefo llowing situations:
R The vehicle is loc ked using thekey.
R The vehicle is loc ked using KEYLESS-GO.
If th eve hicle has been loc ked via Mercedes me
connect, the additional door lock is not activated
(/ page 318).
If th e additional door lock is activated, the doors
cannot be opened from the inside.
% ATer locking you can issue a signal with the
horn. Yo
u can pr event the additional door lock from
being activated bydeactivating interior pr otection
before locking theve hicle (/ page 104). U Unloc
nloc king/opening t
king/opening t he door
he doors fr
s from t
om t he inside
he inside #
U
Unitnit ed Kingdom only
ed Kingdom only :
:obser vethe no tes on
th e additional door lock (/ page 84). #
Pull door handle 1. Centr
Centr
all
ally loc
y loc king and unloc
king and unloc king t
king the v
he vehicle fr
ehicle fr om
om
t
t he inside
he inside #
T
To unloc
o unloc k:
k:press button 1. #
T
To loc
o loc k:
k:press button 2.
The red indicator lamp on button 2lights up
once theve hicle is loc ked.
This does not lock or unlock the fuel /ller 0ap. Opening and closing
85
85

%
Further information on con venience closing
(/ page 97).
If yo u open theta ilgate from outside, it is auto-
matically unloc ked. Pr
Pr
oblems wit
oblems wit h KEYLESS-GO, tr
h KEYLESS-GO, tr oubleshoo
oubleshooting
ting Y
Y
ou can no long
ou can no long er loc
er lock or unloc
k or unloc k t
k the v
he v ehicle using
ehicle using
KEYLESS-GO
KEYLESS-GO
Po ssible causes:
R The function of theke y has been deactivated.
R The key battery is weak or dischar ged. #
Activate the function of theke y (/ page 82). #
Check the battery using the indicator lamp
(/ page 81). #
Replace theke y batter y,if necessary
(/ page 83). #
Use there placement key. #
Use the emer gency keyto lock or unlock
(/ page 88). #
Have theve hicle and keych ecked at a quali-
/ed specialist workshop. Ther Ther
e is int
e is int erf
erfer
erence fr
ence fr om a pow
om a pow er
erful r
ful r adio signal
adio signal
sour
sour ce
ce
Po ssible causes if the function of KEYLESS-GO is
impaired:
R high voltage po wer lines
R mobile phones
R electronic devices (no tebooks, tablets)
R shielding due tome tal objects or induction
loops for electrical gate systems or automatic
bar riers #
Make sure that there is su1cient distance
between theke y and the po tential sou rce of
inter fere nce. A
A
ctiv
ctiv ating/deactiv
ating/deactiv ating t
ating the aut
he automatic loc
omatic loc king f
king fea-
ea-
ture
ture The
vehicle is loc ked automatically when theve hi-
cle is switched on and the wheels are turning
fa ster than walking pace. #
T To activ o activ at
ate:
e: press and hold button 2for
appr oximately /ve seconds until an acoustic
signal sounds. #
T To deactiv
o deactiv at
ate:
e: press and hold button 1for
appr oximately /ve seconds until an acoustic
signal sounds.
The red indicator lamp on button 2lights up
once theve hicle is loc ked. Opening and closing
87 87