service MERCEDES-BENZ B-CLASS HATCHBACK 2021 Workshop Manual

#
Ifth e bonnet can still be liTed slightl y,open
th e bonnet again and close it with a little force
until it engages cor rectl y. Engine oil
Engine oil
Chec
Chec
king t
king t he engine oil lev
he engine oil lev el using t
el using the on-board
he on-board
com
com put
puter
er
R
R eq
eq uir
uir ements:
ements:
R The engine has been warmed up.
R The vehicle is par ked on a le vel sur face.
R The engine is running at idle speed.
R The bonnet is closed.
The engine oil le vel is de term ined during driving.
De term ining the engine oil le vel can take up to
30 minutes with a normal driving style and even
longer with an active driving style. On-board computer:
4 Service 5
Engine oil level
One of thefo llowing message s will appear onthe
inst rument displa y:
R Engine oil level Measuring now: measu rement
of the oil le vel is not yet possible. #
Repeat there qu est aTer a maximum of
30 minutes' driving.
R Engine oil level OK andthe bar display for
indicating the oil le vel on the inst rument dis-
play is green and is between "min" and "max":
th e oil le vel is cor rect.
R Engine oil level Add 1,0 l andthe bar display
fo r indicating the oil le vel on the inst rument
display is orange and is below "min": #
Add 1 l of engine oil.
R Reduce engine oil level andthe bar display for
indicating the oil le vel on the inst rument dis-
play is orange and is abo ve"max": #
Drain o. any excess engine oil that has been
added. Todo so, consult a quali/ed specialist
wo rkshop.
R For engine oil level turn on ignition #
Switch on theve hicle tocheck the engine oil
le ve l.
R Engine oil level System inoperative: The oil
leve l sensor is defective or not connected. #
Consult a quali/ed specialist workshop.
R Engine oil level System currently unavail. #
Close the bonnet.
T T opping up engine oil
opping up engine oil &
W
WARNING
ARNING Risk of burns from hot compo-
nent parts in the engine compartment
Cer tain component parts in the engine com-
partment can be very hot, e.g. the engine, the
cooler and parts of theex haust system. #
Allow the engine tocool down and only
to uch component parts described in the
fo llowing. 340
340
Maintenance and care

&
W
W ARNI NG
ARNI NGRisk of /re and injury from
engine oil
If engine oil comes into contact with hot com-
ponent parts in the engine compartment, it
may ignite. #
Make sure that no engine oil is spilled
next tothe /ller opening. #
Allow the engine tocool o. and thor-
oughly clean the engine oil from compo-
nent parts before starting theve hicle. *
N
NO OTE
TE Engine damage caused byan inco r-
re ct oil /lter, incor rect oil or additi ves #
Do not use engine oils or oil /lters which
do not cor respond tothe speci/cations
ex plicitly prescribed forth e service inter-
va ls. #
Follow the inst ructions on the service
inter val display forch anging the engine
oil and obser vethe prescribed change
inter vals. #
Do not use additives. *
N
NOOTE
TE Damage caused bytopping up too
much engine oil To
o much engine oil can damage the engine or
th e catalytic con verter. #
Have excess engine oil remo ved at a
qu ali/ed specialist workshop. %
Depending on driving st yle, theve hicle con-
sumes up to0.8 litre of oil per 1000 km. The
oil consum ption may be higher than this when
th eve hicle is new or if you frequently drive at
high engine speeds. #
Turn cap 1anti-clockwise and remo veit. #
Top up the engine oil. #
Replace cap 1and turn it clockwise until it
engages. #
Check the oil le vel again (/ page 340). Maintenance and care
341
341

R
Do not polish theve hicle and light-alloy
wheels.
R Only use car washes that cor respond tothe
latest engineering standards.
R Do not use car wash prog rammes with a /nal
hot wax treatment.
R Do not use paint cleaners, bu1ng or polishing
products, gloss preser vers, e.g. wax.
In theev ent of paintwork damage:
R Always ha vepaintwork repairs car ried out at a
qu ali/ed specialist workshop.
R Make sure thera dar sensors function
(/ page 223). N
No
ot
tes on cleaning decor
es on cleaning decor ativ
ative f
e foils
oils Obser
vethe no tes on matt /nish care in thech ap-
te r "No tes on paintwork/matt /nish paintwork
care" (/ page 346). They also apply tomatt dec-
orative foils.
Obser vethe no tes on cleaning decorative foils to
av oid vehicle damage. Cleaning
Cleaning
R For cleaning, use plenty of water and a mild
cleaning agent without additives or abrasive
substances, e.g. a car shampoo appr ovedfor
Mercedes-Benz.
R Remo vedirt immediatel y,where possible,
whilst avoiding rubbing too hard. There is oth-
erwise a risk of damaging the decorative foil
ir re parabl y.
R Ifth ere is dirt on the /nish or if the decorative
fo il is dull: Use thePa int Cleaner recommen-
ded and appr ovedfo r Mercedes-Benz.
R Insect remains: Soak with insect remo ver and
ri nse o. the treated areas aTer wards.
R Bird droppings: Soak with water and rinse o.
aTer wards.
R Topreve ntwa ter stains, dry a foil-wrapped
ve hicle with a soT, absorbent clo thaTer every
car wash.
Av Av oiding damag
oiding damag e t
e to t
o t he decor
he decor ativ
ative f
e foil
oil
R The service life and colouring of decorative
fo ils are impaired by:
- Sunlight -
Tempe rature, e.g. hot air blo wer
- Weather conditions
- Stone chippings and dirt
- Chemical cleaning agents
- Oily products
R Do not use polish on matt decorative foil. Po l-
ishing will ha vethe e.ect of shining thefo il-
wrapped sur face.
R Do not treat matt or st ructured decorative
fo ils with wax.Pe rm anent stains may occur.
Scratches, cor rosive deposits, areas a.ected by
cor rosion and damage caused byincor rect care
cannot alw ays be comple tely re paired. In such
cases, visit a quali/ed specialist workshop.
Yo u can obtain more information on care and
cleaning products from the manufacturer.
In the case of foil-wrapped sur faces, optical di.er-
ences may occur between the sur faces that we re
not pro tected bya decorative foil aTer removing a
decorative foil. Maintenance and care
347
347

+
ENVIR
ENVIR
ONMENT
ONMENT AL NO
AL NOTE
TE Environmen tal
pollution caused byenvironmentally ir re-
sponsible disposal Ty
re sealant contains pollu tants. #
Have the tyre sealant bottle disposed of
professionall y,e.g. at a Mercedes-Benz
Service Centre. #
Stow the tyre sealant bottle, the tyre in0ation
compressor and thewa rning triangle. #
Pull awa
Pull away immediat
y immediat ely.
el y. #
Stop driving aTer appr oximately ten minutes
and check the tyre pressure using the tyre
in0ation compressor.
The tyre pressure must now be at least
130 kPa (1.3 bar/19 psi). &
W WARNING
ARNING Risk of accident due tothe
speci/ed tyre pressure not being attained
If th e speci/ed tyre pressure is not reached,
th e tyre is too badly damaged. The tyre seal-
ant cannot repair the tyre in this instance. The braking and driving
characteristics may be
gr eatly impaired. #
Do not continue driving. #
Consult a quali/ed specialist workshop. Countr
Countr
ies t
ies that hav
hat hav e Mer
e Mercedes-Benz Ser
cedes-Benz Ser vice24h:
vice24h:
yo u will /nd a stic ker with thete lephone number,
e.g. on the B‑pillar on the driver's side. #
Correct the tyre pressure if it is still at least
130 kPa (1.3 bar/19 psi). See the tyre pres-
sure table on the fuel /ller 0ap forva lues.
Incr
Incr easing t
easing t he tyr
he tyre pr
e pressure
essure #
Switch on the tyre in0ation compressor.
Decr
Decr easing t
easing t he tyr
he tyre pr
e pressure
essure #
Remo vethe tyre sealant bottle from the tyre
in0ation compressor. #
Insert the /ller hose in the soc ket of the tyre
in0ation compressor and turn it a quarter turn
clockwise. #
Press pressure release button Cnext to
manome terB.
When t When t he tyr he tyre pr
e pressur
essur e is corr
e is corr ect
ect #
Unscr ewthe /lling hose from theva lve of the
sealed tyre. #
Screw theva lve cap onto theva lve of the
sealed tyre. #
Stow the tyre sealant bottle and the tyre in0a-
tion compressor. #
Drive tothe nearest quali/ed specialist work-
shop and ha vethe tyre, tyre sealant bottle and
/lling hose replaced there. 360
360
Breakdown assistance

&
W
W ARNI NG
ARNI NGRisk of explosion from a frozen
battery
A dischar ged battery may freeze at temp era-
tures slightly abo veor below freezing point.
During starting assistance or battery charging,
battery gas can be released. #
Always allow a battery tothaw before
ch arging it or per form ing starting assis-
ta nce. If
th e indicator/warning lamps in the inst rument
cluster do not light up at low temp eratures, it is
ve ry likely that the dischar ged battery has frozen.
In this case you may neither jump-start theve hi-
cle nor charge the batter y.
The service life of a bat tery that has been thawed
may be dramatically shor tened. The starting char-
acteristics may be impaired, especially at low
te mp eratures.
It is recommended that you ha veath awe d battery
ch ecked at a quali/ed specialist workshop. *
N
NO OTE
TE Damage caused bynume rous or
ex tended attem ptsto start the engine Numerous or
extended attem ptsto start the
engine may damage the catalytic con verter
due tonon-combusted fuel. #
Avoid numerous and extended attem pts
to start the engine. Obser
vethefo llowing points during starting assis-
ta nce and when charging the batter y:
R Only use undamaged jump lead/charging
cables with a su1cient cross-section and
insulated term inal clamps.
R Non-insulated parts of thete rm inal clamps
must not come into contact with other me tal
parts while the jump lead/charging cable is
connected tothe battery/jump-start connec-
tion point.
R The jump lead/charging cable must not come
into contact with any parts which may mo ve
when the engine is running.
R Always make sure that nei ther you nor the bat-
te ry is electros tatically charge d. R
Keep awa y from /re and naked 0ames.
R Do not lean overth e batter y.
Obser vethe additional following points when
ch arging the batter y:
R Only use battery charge rs tested and
appro vedfo r Mercedes-Benz.
R Read the battery charge r's operating inst ruc-
tions before charging the batter y.
Obser vethe additional following points during
starting assistance:
R For starting assistance, only use batteries with
a nominal voltage of 12 V.
R The vehicles must not touch.
R P
P e etr
tr ol engine:
ol engine: only accept starting assistance
if th e engine and exhaust system are cold. S
S
t
tar
ar ting assist
ting assist ance and c
ance and c har
harging t
ging t he 12 V batt
he 12 V batt ery
ery R
R
eq
eq uir
uir ements:
ements:
R The vehicle is secured with the electric par k-
ing brake. Breakdown assistance
363
363

*
N
N O
OTE
TE Damage tovehicle body or suspen-
sion components caused by/tted snow
ch ains On 4MATIC
vehicles, if you /t snow chains on
th ere ar wheels, you can damage vehicle body
or suspension components. #
On 4MATIC vehicles, only /t snow chains
on the front wheels. *
N
NO OTE
TE Damage tothe wheel trim from /t-
ted snow chains If snow
chains are /tted tosteel wheels, the
wheel trims can be damaged. #
Remo vethe wheel trims of steel wheels
before /tting snow chains. Obser
vethefo llowing no tes when using snow
ch ains:
R Snow chains are only permissible for cer tain
wheel/tyre combinations. You can obtain
information about this from a Mercedes-Benz
Service Centre. R
For saf etyre asons, only use snow chains that
ha ve been speci/cally appr oved foryo ur vehi-
cle byMercedes-Benz, or snow chains with
th e same quality standard.
R If snow chains are /tted, the maximum per-
missible speed is 50 km/h.
R V
Vehicles wit
ehicles wit h A
h Activ
ctiv e P
e Par
arking Assist
king Assist: :do not use
Ac tive Parking Assist when snow chains are
/tted.
% You can permanently limit the maximum
speed for driving with winter tyres
(/ page 235).
% You can deactivate ESP ®
to pull away
( / page 227). This allo ws the wheels tospin,
achieving an increased driving forc e. T
T
yr
yr e pr
e pr essure
essure N
No
ot
tes on tyr
es on tyr e pr
e pressure
essure &
W
WARNING
ARNING Risk of accident due toinsu1-
cient or excessive tyre pressure
Un derin0a tedorove rin0ated ty res pose in par-
ticular thefo llowing risks:
R The tyres can burst.
R The tyres can wearexcessively and/or
une venly.
R The driving characteristics as well as the
stee ring and braking characteristics may
be greatly impaired. #
Comply with there commended tyre
pressure and check the tyre pressure of
all tyres, including the spare wheel, regu-
lar ly:
R monthly
R when the load changes
R before embarking on a lon ger journey Wheels and tyres
375
375

R
if operating conditions change, e.g. o.-
ro ad driving #
Adjust the tyre pressure, if necessar y.Ty
re pressure which is too high or too low can:
R Shor tenth e service life of the tyres.
R Cause increased tyre damage.
R Adve rsely a.ect driving characteristics and
th us driving saf ety, e.g. due toaquaplaning. &
W
WARNING
ARNING Risk of accident due torepea-
te d pressure drop in the tyres
The wheels, valves or tyres could be damaged.
To o low a tyre pressure can lead tothe tyres
bursting. #
Examine the tyres forfo re ign objects. #
Check whe ther the tyre has a puncture
or theva lve has a leak. #
Ifyo u are unable torectify the damage,
contact a quali/ed specialist workshop. Information on
there commended tyre pressure
fo rth eve hicle's factor y-/tted tyres can be found
on the tyre pressure table on the inside of the fuel
/ller 0ap (/ page 376).
Use a suitable pressure gauge tocheck the tyre
pressure. The outer appearance of a tyre does not
permit any reliable conclusion about the tyre pres-
sure.
Only cor rect tyre pressures when the tyres are
cold. Conditions for cold tyres:
R The vehicle has been par ked with the tyres out
of direct sunlight for at least thre e hours.
R The vehicle has tr avelled less than 1.6 km.
The vehicle's tyres heat up when driving. As the
te mp erature of the tyres increases, so too does
th e tyre pressure.
V
V ehicles wit ehicles wit h a tyr
h a tyre pr
e pressur
essur e monit
e monit or
oring syst
ing syst em:
em:
yo u can also check the tyre pressure using the
on-board computer.
Not
Not es on tr
es on tr ailer oper
ailer oper ation
ation
Alw ays in0ate there ar axle tyres tothere com-
mended tyre pressures on the tyre pressure table
fo r increased load. T
T
yr
yr e pr
e pr essur
essur e t
e table
able The tyre pressure
table is on the inside of the fuel
/ller 0ap. The tyre pressure
table sho ws there commended
tyre pressure for all tyres appr ovedfo rth is vehi-
cle. The recommended tyre pressures apply for
cold tyres under various operating conditions, i.e.
loading and/or speed of theve hicle. 376
376
Wheels and tyres

If one or more tyre sizes precede a tyre pressure,
th efo llowing tyre pressure information is only
va lid forth ose tyre sizes and their respecti veload
condition.
If th e preceding tyre sizes are complemented by
th e0091 symbol, the tyre pressure information
fo llowing sho wsalternative tyre pressures. Fuel
consum ption may then increase slightl y.
The load conditions "pa rtially laden" and "fully
laden" are de/ned in theta ble for di.erent num-
bers of passengers and amounts of luggage. The
actual number of seats may di.er from this. T T
yr
yr e pr
e pr essur
essur e monit
e monit or
oring syst
ing syst em
em F
F
unction of t
unction of t he tyr
he tyre pr
e pressur
essur e monit
e monit or
oring syst
ing syst em
em
The system checks the tyre pressure and the tyre
te mp erature of the tyres /t tedtotheve hicle by
means of a tyre pressure sensor.
The tyre pressure and the tyre temp erature
appear in the on-board computer (/ page 377).
If th ere is a substantial pressure loss or if the tyre
te mp erature is excessive, you will be warned with
display messages (/ page 469) orthe0077 wa
rning lamp in the inst rument cluster
(/ page 493).
The tyre pressure monitoring system is only an
aid. It is the driver's responsibility toset the tyre
pressure tothere commended cold tyre pressure
suitable forth e operating situation.
In most cases, the tyre pressure monitoring sys-
te m will automatically update the new refere nce
va lues aTer you ha vechanged the tyre pressure.
Yo u can, ho wever, also update there fere nce val-
ues byrestarting the tyre pressure monitoring
system manually (/ page 378).
Syst
Syst em limits em limits
The system may be impaired or may not function
particular lyin thefo llowing situations:
R incor rect refere nce values were ta ught in
R sudden pressure loss caused byafo re ign
object penetrating the tyre, forex ample
R there is a malfunction caused byano ther radio
signal source Chec Chec
king t king t he tyr
he tyr e pr
e pressur
essur e wit
e with t
h the tyr
he tyr e pr
e pressure
essure
monit
monit or
oring sy
ing sy st
stem
em
R
R eq
eq uir
uir ements:
ements:
R The vehicle is switched on.
On-board computer: 4 Service 5
Tyres
One of thefo llowing displa ysappears:
R Current tyre pressure and tyre temp erature of
th e individual wheels: R
Tyre pressures will be displayed after a few
minutes of driving Wheels and tyres
377 377

R
Tyre pressure monitor active :th ete ach-in
process of the system is not yetcomple te. The
tyre pressures are already being monitored. #
Compare the tyre pressure with there com-
mended tyre pressure forth e cur rent ope rat-
ing condition (/ page 376).Additionall y,
obser vethe no tes on cold tyres
(/ page 375).
% The values displa yed in the on-board com-
puter may deviate from those of the tyre pres-
sure gauge as they referto sea le vel.At high
ele vations, the tyre pressure values indicated
by a pressure gauge are higher than those
shown bythe on-board computer. In this case,
do not reduce the tyre pressure.
R
R est
est ar
arting t
ting t he tyr
he tyr e pr
e pressur
essur e monit
e monit or
oring syst
ing syst em
em
R
R eq
eq uir
uir ements:
ements:
R The recommended tyre pressure is cor rectly
set forth ere specti veoperating status on all of
th e wheels (/ page 375).
Re start the tyre pressure monitoring system in the
fo llowing situations:
R The tyre pressure has changed. R
The wheels or tyres ha vebeen changed or
ne wly /tted.
On-board computer: 4 Service 5
Tyres #
Swipe down wards on Touch Control on the
leT-hand side of the steering wheel.
The Use current pressures as new reference
values? message is shown in the Instrument
Displa y. #
Torestart, press Touch Control on the leT-
hand side of the steering wheel.
The Tyre press. monitor restarted message is
shown in the Instrument Displa y.
Cur rent wa rning message s are deleted and
th eye llow 0077 warning lamp goes out.
ATer you ha vebeen driving for a few minutes,
th e system checks whe ther the cur rent tyre
pressures are within the speci/ed range. The
cur rent tyre pressures are then accep ted as
re fere nce values and monitored.
Be sure toalso pay attention tothefo llowing rela-
te dto pic:
R Notes on tyre pressure (/ page 375) T
T
yr
yr e pr
e pr essur
essur e loss w
e loss w ar
arning syst
ning syst em
em F
F
unction of t
unction of t he tyr
he tyre pr
e pressur
essur e loss w
e loss w ar
arning syst
ning syst em
em
The tyre pressure loss warning system warnsthe
driver bymeans of display messages when there
is a se vere tyre pressure loss.
Syst
Syst em limits
em limits
The system may be impaired or may not function
particula rly in thefo llowing situations:
R incor rect refere nce values were ta ught in
R sudden pressure loss caused byafo re ign
object penetrating the tyre, forex ample
R aneven pressure loss on more than one tyre
occurs
The system has a restric ted or dela yed function
particular lyin thefo llowing situations:
R poor ground conditions, e.g. snow or grav el
R driving with snow chains
R when adopting a very sporty driving st yle with
high cornering speeds or sudden acceleration
R driving with a very heavy or lar getrailer
R driving with a high load 378
378
Wheels and tyres

The tyre pressure loss
warning system is only an
aid. It is the driver's responsibility toset the tyre
pressure tothere commended cold tyre pressure
suitable forth e operating situation and tocheck
it.
Be sure toalso obser vethefo llowing fur ther rela-
te d subjects:
R Notes on tyre pressure (/ page 375)
R Displ aymessages about the tyres
(/ page 469)
R
R est est ar
arting t
ting t he tyr
he tyr e pr
e pressur
essur e loss w
e loss w ar
arning syst
ning syst em
em
R
R eq
eq uir
uir ements:
ements:
R The recommended tyre pressure is cor rectly
set forth ere specti veoperating status on all
wheels.
Re start the tyre pressure loss warning system in
th efo llowing situations:
R The tyre pressure has changed.
R The wheels or tyres ha vebeen changed or
ne wly /tted. On-board computer:
4 Service 5
Tyres #
Swipe down wards on Touch Control on the
leT-hand side of the steering wheel.
The Run Flat Indicator active Restart mes-
sage is shown in the displa y. #
Tobegin restart, press Touch Control on the
leT-hand side of the steering wheel.
The Tyre pressure now OK? message is
shown in the displa y. #
Select Yes. #
Tocon/rm restart, press Touch Control on the
leT-hand side of the steering wheel.
The Run Flat Indicator restarted message is
shown in the displa y.
ATer you ha vedriven for a few minutes, the
tyre pressure loss warning system monitors
th e set tyre pressures of all the tyres.
Be sure toalso pay attention tothefo llowing rela-
te dto pic:
R Notes on tyre pressure (/ page 375) Wheel c
Wheel c
hange
hange N
No
ot
tes on selecting,
es on selecting, /tting
/ttingand r
and replacing tyr
eplacing tyr es
es &
W
WARNING
ARNING Risk of accident due toincor-
re ct wheel and tyre dimensions
If wheels and tyres of the wrong size are /t ted,
th e service brakes or components in the brake
system and in the wheel suspension may be
damaged. #
Alwaysre place wheels and tyres with
th ose that ful/l the speci/cations of the
original part.
Fo r wheels, pay attention tothefo llowing:
R Designation
R Type
Fo r tyres, pay attention tothefo llowing:
R Designation
R Manufacturer
R Type Wheels and tyres
379
379