MERCEDES-BENZ A-CLASS SEDAN 2021 Service Manual

R
The seat beltmustbe routed acr oss thecen‐
te rof theshoulder andaslow do wn across
th ehips aspossible.
R The shoulder sectionoftheseat beltshould
no tto uc hyo ur neck nor berouted unde r
yo ur arm or behin dyo ur bac k.
R Avoid wearing bulk yclo thing, e.g. awint er
coat .
R Push thelap belt down asfaras possi ble
acr oss your hips andpulltight wit hth eshoul‐
der sect ionofthebelt. Neverro uteth elap
belt across your abdom en.
Pr egn ant women mustals ota ke par ticular
car ewit hth is.
R Neverro uteth eseat beltacross shar p,poin‐
te d, abr asiv eor fragile objec ts.
R Onlyone person should useeachseat beltat
an yone time. Neverall ow babies andchil‐
dr en totrave lsitt ing onthelap ofano ther
ve hicle occupant.
R Neversecur eobjects withaseat beltifth e
seat beltisalso being usedbyone ofthe
ve hicle's occupants. Alwaysobser vethe
ins truct ions forloa ding theve hicle when secur
ingobject s,lugg ageor loads
(/ page98).
Also ensur eth at no obj ect s,e.g .a cus hion ,
ar eeve rpla ced between aper son and the
seat.
The seat belts onthefo llo wing seats areeq uip‐
ped withaspec ialseat beltretract or:
R Front passeng erseat
R Rear seat s
Ac tivateor deacti vate thespecial seatbelt
re tract or(/ page 56).
If ch ildr enaretra veling intheve hicle, besur eto
obser vetheins truction sand safetyno teson
"Chi ldren intheve hicle" (/page52). Limitations
ofthepr otection prov ided bythe
seat belt &
WARNIN GRisk ofinju ryor deat hdue to
an incorrect sea tpos ition
The seatbel tdoe sno tof ferth eint ended
le ve lof protect ion ifyo uha ve notmo vedth e
seat backres tto an almos tve rtical posit ion.
Yo uco uld slip beneathth eseat beltand
injur eyo urself . #
Adjus tth eseat proper lybef orecom‐
menc ingyour jour ne y. #
Alw aysensur eth at theseat backres tis
in an almos tve rtical posit ionand that
th eshoulder beltisrouted acr oss the
cent erofyour sho ulder . &
WARNIN GRisk ofinju ryor deat hwhen
additional restra int systems areno tused
fo rper sons withasmal lerstatur e
Pe rsons under 5ft (1.50 m)ta llcan notwe ar
th eseat beltcorrectly without asuit able
additional restra int system. Occ
upant safety 39

#
Alw ayssecur eper sons under 5ft
(1 .50 m)tallin asuit able restra int sys‐
te m. &
WARNIN GRisk ofinju ryor deat hdue to
damag edormodif iedseat belts
Seat belts cannotprov ide protect ion inthe
fo llo wing situat ions:
R The seat beltisdamag ed,has been modi‐
fi ed, isex treme lydirty, bleac hedordyed
R The seat beltbuckleisdamag edor
ex treme lydir ty
R Modif ication sha ve been made tothe
Emerg encyTensi oni ng Device ,sea tbe lt
anc horageor sea tbe ltre tract or
Sea tbe lts ma ysu stain non-visi ble damag ein
an acc iden t,e.g .due toglass splin ters.
Modif iedordamag edseat belts could tear or
fa ilin theev ent ofan acciden t,forex am ple.
Modif iedEmerge ncy Tensi oni ng Device s
cou ldacci dentally trig ge ror failto function
as intended . #
Nevermodify theseat beltsystem, for
ex am ple theseat belt, seatbeltbuckle,
Emer gency Tensi oni ng Device ,sea tbe lt
anc horageand seatbe ltre tract or. #
Makesur eth at theseat belts are
undamag ed,notwo rnand clean. #
Alw aysha ve theseat belts checked
immed iatelyaf te ran accide ntata
qu alif ied spec ialistwo rkshop. Onl
yuse seat belts whichha ve been approved
fo ryo ur vehicle byMer cedes-Ben z. &
WARNIN GRisk ofinju ryor deat hfrom
deplo yedpy rotech nic Emerg encyTen‐
si oni ng Device s
Py rotech nic Emerg encyTensi oni ng Device s
th at have been deployedar eno long eroper a‐
tion aland areunable toper form their inten‐
ded protect ive func tion. #
Ther efor e, have deplo yedpy rotech nic
Emerg encyTensi oni ng Device simm edi‐
at ely replaced ataqu alif ied spec ialist
wo rkshop. Mer
cedes-Benz recomme ndsthat youha ve the
ve hicle towe dto aqu alif ied spec ialistwo rkshop
af te ran accide nt.
* NO
TEDama gecau sed bytrap ping the
seat belt If
an unused seatbeltisno tfully retract ed,it
ma ybe come trap pe din thedoor orinthe
seat mechanism. #
Alw aysensur eth at an unus edseat belt
is full yre tract ed. Fa
stening seatbelts If
th eseat beltispulled quickl yor shar ply, the
seat beltretract orlock s. The seat beltstra pcan‐
no tbe pulled outanyfur ther. 40
Occupant safety

#
Alw ayseng ageseat belttongu e2 ofthe
seat beltintoseat beltbuckle1 ofthecor‐
re sponding seat.
Ve hicl eswith automatic front passen gerair‐
bag shutoff: *
NO
TEDep loym ent oftheEmer gency
Te nsi oni ng Device andside airba gwh en
th efront passeng erseat isunocc upied If
th eseat belttongu eis eng aged intheseat
belt buckleoftheunocc upied front
passeng erseat, theEmer gency Tensi oni ng
De vice andtheside airbag mayalso deplo y
in theev ent ofan acciden talong withot her
sy stems. #
Onlyone person should useeachseat
belt atanyone time. Ve
hicl eswithout automatic front passen ger
airb agshu toff:
* NO
TEDep loym ent oftheEmer gency
Te nsi oni ng Device when thefront -
passeng erseat isunocc upied If
th eseat belttongu eis eng aged intheseat
belt buckleoftheunocc upied front -
passeng erseat, theEmer gency Tensi oni ng
De vice mayal so deploy intheev ent ofan
acciden talong withot her systems. #
Onlyone person should useeachseat
belt atanyone time. Seat
beltadjustm ent function Ve
hicl eswith PRE-S AFE®
:Af tera front seat
belt hasbeen fastened, theaut omatic seatbelt
adjus tmentma yappl ya cer tain tigh tening forc e.
Do nothold theseat belttight lywhile itis
adjus ting.
Yo ucan activat eand deac tivateth eseat belt
adjus tmentfunc tion using themultimedia sys‐
te m (/ page41 ). Ac
tiv atin g/deac tivatin gse at beltadjus tment
vi athe multi mediasy stem Multi
media system:
4 © 5
Set ting s5
Vehicle #
Activateor deacti vate Belt Adjus tment . Occup
antsafety 41

Re
leasing seatbelts #
Press there lease buttonintheseat belt
buc kleand guide theseat beltbackwit hth e
seat belttongu e. Se
at beltwa rning funct ionforthe driver and
fr on tpass enger The
00E9 seatbeltwarning lam pin theins tru‐
ment displa yis are minder that all vehicle occu‐
pants mustwe artheir seat belts correctly .
The 00E9 seatbel twa rning lam plight sup forsix
seconds everytim eth eve hicle isstar ted.
In addition, awa rning tone maysou nd.
Whe nth edr iver's andfront passeng er'sdoor s
ar eclosed andthedr iver and front passeng er
ha ve fastened their seat belts, theseat belt
wa rning goes out.
In thefo llo wing cases ,th eseat beltwarning
light sup dur ing ajour neyif:
R The vehicle speed exceeds 15mp h
(25 km/ h)and thedr iver's orfront
passeng erseat beltisno tfa stened. R
The driver or front passeng erunf astens their
seat beltwhile theve hicle isin mo tion. Airbags
Ov
ervie wof airbags 1
Driver's knee airbag
2 Driver's airbag
3 Front passeng erairbag
4 Front passeng erknee airbag
5 Windo wcur tain airbag
6 Side airbag The
installation locationofan airbag isident ified
by theAIRB AGsymbol.
When enabled, anairbag canprov ide addition al
pr otect ion forth ere spectiv eve hicle occupant.
Pot entialprotect ion prov ided byeac hairbag:
R Knee airbag: thigh, knee and lowe rleg
R Driver's airbag,front pass engerairb ag:head
and ribcag e
R Windo wcur tain airbag: head
R Side airbag: ribcag eand pelvis
* NO
TEMer cedes-AMG vehicles #
Obser vetheno tesin theSupplement .
Yo uco uld other wise failto recogni ze
da ngers. &
WARNIN GRisk ofinju ryor deat hif th e
co-dr iver airba gis ena bled
If th eco- driver airbag isenabled, ach ild on
th eco- driver seat maybe stru ck bytheco-
dr iver airbag during anacciden t. 42
Occupant safety

NEVER
useare ar wa rd-faci ng child restra int
sy stem onaseat withan ENABL EDFRONT
AIRB AG;DE ATHor SERIOU SINJU RYtothe
CH ILD can occur . When
installing ach ild restra int system onthe
fr ont passeng ersea t,obse rveth eve hicle-spe‐
cif icinf ormation (/page61 ).Al so ,alw ays
obser vetheno teson rear wa rd-faci ng or
fo rw ard-f acin gch ild restra int systems onthe
fr ont passeng ersea t.
Inf ormation onaut omatic front passen ger
airbag shutoff
The front passeng erairbag canonly bedep loye d
in an acc ident ifth ePA SSENGER AIRBAGOF F
ind icat orlam pis off.Ifth efront passeng erseat
is occupied, makesur e,bo th bef oreand during
th ejour ney,that thest atus ofthefront
passeng erairbag iscor rect (/ page 47). *
NO
TEImpo rtant poin tsto remember if
th efront passeng erseat isunocc upied In
an acciden t,th ecom ponen tsof the
re stra int system maydeplo yunnec essarily
on thefront passeng erside if:
R Ther ear ehea vyobjec tson thefront
passeng erseat.
R The seat belttongu eis eng aged inthe
seat beltbuckleofthefront passeng er
seat andthefront passeng erseat is
unocc upied. #
Stow object sin asuit able place. #
Onlyone person should useeachseat
belt atanyone time. Depending
onthede tected acci dent situation,
th ewindo wcur tain airbag onthefront
passeng erside maydeplo y.The airbag is
deplo yedre ga rdless ofwhe ther thefront
passeng erseat isoccupied. Pr
otectiv ecap acit yof theair bags Dep
endingontheacciden tsituation ,an airbag
ma ysupplement thepr otect ion offere dby acor ‐
re ctly fastened seatbelt. &
WARNIN GRisk ofinju ryor deat hdue to
an incorrect sea tpos ition
If yo ude viat efrom thecor rect sea tpos ition,
th eairbag cannotper form itsintended pro‐
te ctiv efuncti on.
Eac hve hicle occupant mustmak esur eof the
fo llo wing:
R Fasten seat belts correctl y.Pregnant
wo men mustta ke par ticular careto
ensur eth at thelap belt neverlie sacr oss
th eabdomen.
R Adoptth ecor rect sea tpos ition and keep
as faraw ay as poss iblefrom theairbags.
R Obser vethefo llo wing informatio n. #
Alw aysmak esur eth at ther ear eno
objec tsbetween theairbag andvehicle
occupant. Occupant
safety 43

To
avo idtherisk sre sulting from thedeplo yment
of an airbag, eachve hicle occupant must
obser vethefo llo wing informatio nin par ticular :
R Beforest ar tin gyo ur jour ne y,adjus tyo ur seat
co rrect ly;th edr iver's seat andfront
passeng erseat should bemo vedas farbac k
as possi ble.
When doingso,alwaysobser vetheinf orma‐
tion onthecor rect driver's seatpos ition
(/ page 87).
R Onlyhold thesteer ing wheel bythesteer ing
wheel rim. This allows theairbag tobe fully
deplo yed.
R Alw ayslean agains tth eseat backres twhen
th eve hicle isin mo tion. Donotlean forw ards
or agains tth edoor orside windo w.Youma y
ot her wise beinthedeplo yment area ofthe
airbag s.
R The occupant smus talw ayske ep their feet
on thefloor .Do notput your feet on the
coc kpit, forex am ple. Your feet ma yot her‐
wise beinthedeplo yment area oftheairbag.
R Ifch ildr enaretrav eling intheve hicle,
obser vetheadditional notes(/ page52). R
Alw aysst or eand secur eobject scor rectl y.
Objects intheve hicle interior maypr eve ntan
ai rba gfrom func tioning correctly .Eac hve hicle
occupant mustalw aysmak esur eof thefo llo w‐
ing inpar ticular :
R Ther ear eno people, animals orobje cts
be tween theve hicle occupants andanair‐
bag.
R Ther ear eno object sbe tween theseat, door
and door pillar (B-pillar).
R Ther ear eno har dobjec ts,e.g. coat hangers,
hanging onthegr ab handles orcoat hooks.
R Ther ear eno accessor ypar ts,suc has mobile
na vig ation devices, mobile phones orcup
holder s,wit hin thedeplo yment area ofan air‐
bag, e.g.onthecoc kpit, onthedoor ,on the
side windo wor on theside trim.
In addition, nocon nect ingcables, tensi oni ng
st ra ps orretainin gst ra ps mus tbe routed or
att ached totheve hicle within thedeplo y‐
ment area ofan airbag. Alwayscom plywit h
th eaccessor ymanuf acturer'sinstallation
ins truct ions and, inpar ticular ,th eno teson
suit able places forins tallation . R
Ther ear eno hea vy,shar p-edg edorfra gile
obje ctsin thepoc kets of your clo thing. Store
suc hobject sin asuit able place. Limit
edprotection prov ided byairbags &
WARNIN GRisk ofinju rydue tomodif i‐
cations totheco verof an airb ag
If yo umod ifytheco verof an airb agoraffix
object ssuc has sticke rs to it,theairbag may
no long erfunc tion correctly . #
Nevermodify theco verof an airb agand
do notaf fix obje ctstoit. The
installation locationofan airbag isident ified
by theAIRB AGsymbol (/page42). &
WARNIN GRisk ofinju ryor deat hdue to
th euse ofunsuit ableseat covers
Due touns uitable seat covers,th eairbags
cann otprotect vehicle occupants asinten‐
ded. 44
Occupant safety

In
addi tion, theoper ation oftheaut omatic
fr ont passeng erairbag shutoffcould be
re strict ed. #
Yousho uld onlyuse seat covers that
ha ve been approved forth ecor respond‐
ing seats byMer cedes-Ben z. &
WARNIN GRisk ofinju rydue tomalfu nc‐
tioning sensorsin thedoor
The func tion oftheairbags canbeimpair ed
due tomodif icationsorincor rect wo rkper‐
fo rm ed on thedoor sor door trim, orifth e
door sar edamag ed. #
Nevermodify thedoor sor par tsof the
door s. #
Alw aysha ve wo rkon thedoor sor door
tr im car ried out ataqu alif ied spec ialist
wo rkshop. &
WARNIN GRisk ofinju rydue todeplo yed
airbag
A deplo yedairbag nolong eroffers anypr o‐
te ction. #
Have theve hicle towe dto aqu alif ied
spec ialistwo rkshop inorder tohave the
deplo yedairbag replaced. Ha
ve deplo yedairbags replaced immediat ely. St
atus ofthefront passeng erfront airbag Fu
nction oftheaut oma ticfront passeng er
air bag shutoff
The automatic front passeng erairbag shutoffis
able todetect whe ther thefront passeng erseat
is occupied byaper son orach ild restra int sys‐
te m. The front pass engerairb agand front
pass engerknee airbagareenabl edordisa bled
accor dingly. &
WARNIN GRisk ofinju ryor deat hdue to
object sunder theco- driver seat
Objec tstrapped undertheco- driver seat can
int erfere wit hth efunc tion oftheaut omatic
co- driver airbag shutoffor damag eth esy s‐
te m. #
Donotst or ean yobject sunder theco-
dr iver seat. #
When theco- driver seat isoccupied,
mak esur eth at no obj ect sar etrapped
unde rth eco- driver seat. When
installing ach ild restra int system onthe
fr ont passeng ersea t,alw aysmak esur eof the
fo llo wing:
R Ensur eth at thech ild restra int system isposi‐
tion edcor rectl y(/ page 51).
R Alw ayscom plywithth ech ild restra int sys‐
te m manuf acturer'sinstallation instruct ions .
R Neverpla ceobjects (e.g.cushi ons)under or
behi ndthech ild restra int system.
R Fully re tract theseat cushion lengthadjus t‐
ment .
R The entire base ofthech ild restra int system
mus talw aysre st on thesitt ing surface ofthe
fr ont passeng ersea t.
R The backres tof thefo rw ard-f acin gch ild
re stra int system mus t,as faras possi ble,be Occupa
ntsaf ety 45

re
sting ontheseat backres tof thefront
passeng erseat.
R The child restra int system mus tno tto uc hth e
ro of or be put under stra in by thehead
re stra int s.Ad jus tth eseat backres tinclin a‐
tion andthehead restra int setting accord‐
ing ly. &
WARNIN GRisk ofinju ryor deat hdue to
object sbe tween theseat surface and
th ech ild restra int system
Objec tsbetween thesitt ing surface and the
ch ild restra int system could affect thefunc ‐
tion oftheaut omatic co-driver airbag shut‐
of f. #
Donotplace anyobjec tsbetween the
sitting surface and thech ild restra int
sy stem. #
The entire base ofthech ild restra int
sy stem mus talw aysre st on thesitt ing
sur face oftheco- driver seat. #
The backres tof thefo rw ard-f acin gch ild
re stra int system mus t,as faras possi ‐ ble,
beresting ontheseat backres tof
th eco- driver seat. #
Alw ayscom plywit hth ech ild restra int
sy stem manuf acturer'sinstallation
ins truct ions . A
per son onthefront passeng erseat must
obser vethefo llo wing informatio n:
R Fasten seat belts correctl y(/ page 38).
R Sitinan almos tupr ight seatposi tion with
th eir bac kag ains tth eseat backres t.
R Sitwithth eir feet resting onthefloor ,if pos‐
sible.
The front passeng erairbag mayot her wise be
disabl edbymis take ,fo rex am ple, inthefo llo w‐
ing situat ions:
R The front passen gertr ansf ersth eir weight by
suppor tingthemselv eson ave hicle armr est.
R The front passeng ersits insuc hawa yth at
th eir weight israised from thesitt ing sur‐
fa ce. &
WARNIN GRisk ofinju ryor deat hdue to
a disable dfron tpasse nger airbag
The fron tpasse nger airbag isdisable dwhen
th ePA SSENGER AIRBAGOF Find icat orlam p
is lit.
A per son inthefront passeng erseat could
th en, forex am ple, com eint ocon tact with
th eve hicle interior ,especially ifth eper son is
sitt ing tooclose tothecoc kpit.
If th efront passeng erseat isoccupied,
alw aysensur eth at:
R The classificat ion oftheper son inthe
fr ont passeng ersea tis cor rect and the
fr ont passeng erairb agisenabl edordisa ‐
ble din accor dance withth eper son inthe
fr ont passeng ersea t.
R The front passeng ersea thas been moved
as farbac kas possi ble.
R The person isseat edcor rectl y. #
Both bef oreand during thejour ney,
ensur eth at thest atus ofthefront
passeng erairbag iscor rect. 46
Occup antsafety

If
th efront passeng erseat isoccupied, theclas‐
sif ication oftheper son orchild restra int system
on thefront passeng erseat take splace afte rth e
fr ont passeng erairb agshut offself-t est.The
PA SSENGER AIRBAGind icat orlam psdispla yth e
st atus ofthefront passeng erairbag.
Alw aysobser vetheno teson thefunc tion ofthe
PA SSENGER AIRBAGind icat orlam ps
(/ page47 ). Fu
nction ofthePA SSEN GERAIRBAGindic a‐
to rlam ps Se
lf-te st of aut oma ticfront passeng erair bag
shu toff
When theignition isswitc hedon,aself-t estis
per form ed dur ing whic hth etw oPA SSENGER
AIR BAGON and OFFind icat orlam pslight up
simul taneou sly. The
status ofthefront passeng erairbag isdis‐
pla yedvia thePA SSENGER AIRBAGind icat or
lam psafte rth eself-t est:
R ON islit:th efront passeng erairbag may
deplo ydur ing anacciden t.
The indicat orlam pgoes outafte rapp rox‐
ima tely 60 seco nd s.
R ON andOF Far eno tlit :th efront passeng er
airbag maydeplo ydur ing anacciden t.
R OFF islit:th efront passeng erairbag isdisa‐
bled. Itwill then notbe deplo yedin theev ent
of an acciden t.
If th ePA SSENGER AIRBAGON indicat orlam pis
of f,on lythePA SSENGER AIRBAGOF Find icat or
lam psho wsthest atus ofthefront passeng er
airbag. ThePASSENGER AIRBAGOF Find icat or
lam pma ybe litcon tinuousl yor be off.
If th ePA SSENGER AIRBAGOF Find icat orlam p
and the0075 restra int system warning lam p
light upsimult aneousl y,thefront passeng erseat
ma yno tbe used. Alsointhis case, donotins tall
a ch ild restra int system onthefront passeng er
seat. Have theaut omatic front passeng erairbag Occ
upant safety 47

shut
offch eckedand repair edimmediat elyat a
qu alif ied spec ialistwo rkshop.
St atus displa y
If th efront passeng erseat isoccupied, ensure,
bo th bef oreand during thejour ney,that thest a‐
tus ofthefront passeng erairbag iscor rect for
th ecur rent situa tion.
Af terin st alli ng are ar wa rd-faci ng child
re stra int system onthefront passeng er
seat :PA SSENGER AIRBAGOF Fmus tbe litcon ‐
tin uousl y. &
WARNIN GRisk ofinju ryor deat hwhen
using are ar wa rd-faci ng child restra int
sy stem while thefront passeng erairbag
is enabled
If yo usec ureach ild inare ar wa rd-faci ng
ch ild restra int system onthefront passeng er
seat andthePA SSENGER AIRBAGOF Find i‐
cat orlam pis off,th efront passeng erairbag
can deplo yin theev ent ofan acciden t.
The child could bestru ck bytheairbag. Alw
aysensur eth at thefront passeng erair‐
bag isdisabled. ThePASSENGER AIRBAG
OFF indicat orlam pmus tbe lit.
NEVER useare ar wa rd-faci ng child restra int
sy stem onaseat withan ENABL EDFRONT
AIRB AG;DE ATHor SERIOU SINJU RYtothe
CH ILD can occur . When
installing ach ild restra int system onthe
fr ont passeng ersea t,obse rveth eve hicle-spe‐
cif icinf ormation (/page61 ).
De pend ing on thech ild restra int system and the
st atur eof thech ild, thePA SSENGER AIRBAG
OFF indicat orlam pma ybe off.In this case, do
no tins tallth ere ar wa rd-faci ng child restra int
sy stem onthefront passeng erseat.
Ins tead, installth ere ar wa rd-faci ng child
re stra int system onasuit able rear seat .
Af terin st alli ng afo rw ard-f acin gch ild
re stra int system onthefront passeng er
seat :depen dingonthech ild restra int system
and thest atur eof thech ild, PASSENGER AIR
BA GOF Fma ybe litcon tinuousl yor be off.
Alw aysobser vethefo llo wing informatio n. &
WARNIN GRisk ofinju ryor deat hdue to
inc orrect pos itioning ofthefo rw ard-
fa cing child restra int system
If yo usec ureach ild inafo rw ard-f acin gch ild
re stra int system onthefront passeng erseat
th at isposit ioned tooclose tothecoc kpit, in
th eev ent ofan acciden t,th ech ild could:
R com eint ocon tact with par tsof theve hi‐
cle's interior ifth ePA SSENGER AIRBAG
OFF indicat orlam pis lit, forex am ple
R bestru ck bytheairbag ifth ePA SSENGER
AIR BAGOF Find icat orlam pis off #
Alw aysmo vethefront passeng erseat
as farbac kas possi bleand fully retract
th eseat cushion lengthadjus tment.
While doing so,alwaysmak esur eth at
th eshoulder beltstra pis cor rectl y
ro uted from theseat beltoutle tof the
ve hicle totheshoulder beltguide on
th ech ild restra int system. Theshoulder
belt stra pmus tbe routed forw ards and
do wn wardsfrom theseat beltoutle t.If 48
Occupant safety