2021 MERCEDES-BENZ A-CLASS HATCHBACK vehicle electrical system

Changing bulbs (only
forve hicles with hal-
ogen headlamps) ......................................... 143
Wi ndsc reen wipers and windscreen
wa sher system ............................................ 145
Mir rors ........................................................ 149 Climat
Climat
e contr
e control ol........................................... 153 153
Overview of climate control systems ............ 153
Operating the climate control system .......... 154 Dr
Dr
iving and par
iving and par king
king..................................... 162 162
Driving ........................................................1 62
DY NAMIC SELECT switch ........................... .178
Manual transmission ................................... 181
Au tomatic transmission .............................. .183
Fu nction of the 4MATIC ...............................1 87
Re fuelling .................................................... 188
Charging the high-voltage battery (plug-in
hy brid) ........................................................ 194
Pa rking .......................................................2 11
Driving and driving saf ety sy stems ............... 219
Tr ailer hitch ................................................ .270
Bicycle rack function ................................... 274
Ve hicle towing instructions .......................... 276 Ins
Ins
tr
trument displa
ument displa y and on-boar
y and on-boar d com-
d com-
put
put er
er........................................................... 277 277
No tes on the inst rument display and on-
board computer .......................................... 277
Overview of instrument display .................... 278
Overview of buttons on the steering wheel ... 279
Operating the on-board computer ................2 79
Fu nction of the po wer me ter (plug-in
hy brid) ........................................................ 281
Fu nction of the electric mo tor po wer
av ailability displ ay(plug-in hybrid) ................ 281
Displaying the po wer me ter (plug-in
hy brid) ........................................................ 282
Overview of displa ysinthe inst rument
display ........................................................ 282
Head-up display .......................................... 282 MBUX multimedia syst MBUX multimedia syst
em
em........................... .285
285
Overview and operation ............................... 285
System settings .......................................... 294
Plug-in hybrid settings ................................ .298
Na vigation .................................................. .299
Te lephone ................................................... 308
Mercedes me app ....................................... 311 Mercedes-Benz emer
gency call system ....... 320
Ra dio & media ............................................ .324
Sound settings ............................................ 329 Maint Maint
enance and car
enance and car e
e................................. 330 330
ASS YST PLUS service inter val display .......... 330
Engine compartment ................................... 331
Cleaning and care ....................................... 337 Br Br
eakdo
eakdo wn assist
wn assist ance
ance................................. 346 346
Emer gency .................................................. 346
Flat tyre ...................................................... 348
Battery (vehicle) .......................................... 354
To w- starting or towing away ........................ 358
Electrical fuses ............................................ 364 Wheels and tyr Wheels and tyr
es
es......................................... 368 368
No tes on noise or unusual handling char-
acteristics ................................................... 368
No tes on regula rly inspecting wheels and
tyres .......................................................... .368
No tes on snow chains ................................. 368
Ty re pressure .............................................. 369 Contents
3 3

*
N
NO
OTE
TE Damage totheve hicle due todriv-
ing toofast and due toimpacts tothe
ve hicle underbody or suspension compo-
nents In
thefo llowing situations, in particular, there
is a risk of damage totheve hicle:
R theve hicle becomes grounded, e.g. on a
high kerb or an unpa vedro ad
R theve hicle is driven toofast ove r an obsta-
cle, e.g. a kerb, speed bump or po thole
R a heavy object st rike sth e underbody or
suspension components
In situations such as these, damage tothe
body, underbody, suspension components,
wheels or tyres may not be visible. Compo-
nents damaged in this wa y can un expectedly
fa il or, in the case of an accident, may no lon-
ge r absorb there sulting forc e as intended.
If th e underbody panelling is damaged, 0am-
mable materials such as lea ves, grass or twigs
can collect between the underbody and the
underbody panelling. These materials may ignite if
they come into contact with hot parts
of theex haust system. #
Have theve hicle checked and repaired
immediately at a quali/ed specialist
wo rkshop.
or #
If driving saf ety is impaired while con-
tinuing your journe y,pull over and stop
th eve hicle immediatel y,while paying
attention toroad and tra1c conditions,
and contact a quali/ed specialist work-
shop. Plug-in h Plug-in h
ybr
ybr id
id
Hybrid vehicles ha vea combustion engine and an
elect ric mo tor.The energy supply for operating
th eve hicle elect rically is pr ovided bythe high-
vo ltage on-board electrical system. &
D
DAN
AN GER
GER Risk of death and /re due to
modi/ed and/or damaged components of
th e high-voltage on-board electrical sys-
tem
The vehicle's high- voltage on-board electrical
system is under high voltage. If you modify
component parts in theve hicle's high- voltage
on-board electrical system or touch damaged
component parts, you may be electrocuted. In
addition, modi/ed and/or damaged compo-
nents may cause a /re.
In theeve nt of an accident or impact tothe
ve hicle underbod y,components of the high-
vo ltage electrical system may be damaged
although the damage is not visible. #
Never make any modi/cations tothe
high- voltage on-board electrical system. #
Do not switch on or use theve hicle if its
high- voltage on-board electrical system
components ha vebeen modi/ed or dam-
aged. 28 28
General no
tes

#
Neverto uch damaged components of
th e high-voltage on-board electrical sys-
te m. #
ATer an accident, do not touch any com-
ponents of the high-voltage on-board
electrical system. #
ATer an accident, ha vetheve hicle trans-
por tedawa y. #
Have the components of the high-voltage
on-board electrical system checked at a
qu ali/ed specialist workshop and
re placed if necessar y. The components of
the high-voltage on-board
electrical system are mar ked with yellow warning
stic kers. The cables of the high-voltage on-board
electrical system are orange.
Ve hicles with hybrid systems generate signi/-
cant lyless noise when stationary and when being
driven than vehicles with combustion engines.
When driving in elect ric mode, theve hicle may
not be heard by otherroad users due tothe signif-
icantly reduced noise generated. It is
forth is reason that theve hicle is equipped
with a sound generator, which ser ves as an acous-
tic vehicle alerting system (A VAS). Declar
Declar
ations of conf
ations of conf or
ormity and not
mity and not es on dr
es on driving
iving
in
in di.er
di.er ent
entcountr
countr ies
ies Electr
Electr
omagne
omagne tic com
tic compatibility
patibility The elect
romagnetic compatibility of theve hicle
components has been checked and certi/ed
according tothe cur rently valid version of Regula-
tion UN-R 10. v
v
ehicle inst
ehicle inst alled r
alled radio com
adio com ponents
ponents Onl
Onl
y f
y for EU and EFT
or EU and EFT A countr
A countries and countr
ies and countr ies t
ies that
hat
r
r ecognise t
ecognise t he EU manuf
he EU manuf actur
acturer's declar
er's declar ation of
ation of
conf
conf or
ormity:
mity: The
following information applies toall wireless
components of theve hicle and of the information systems and communication devices integ
rated in
th eve hicle:
The manu facturers of the wireless components
ensure that all wireless components ins talled in
th eve hicle comply with Directi ve2014/53/EU.
The full texts of the EU declarations of conformity
are available at thefo llowing web address:
https://moba.i.daimler.com/mar kets/ece-r ow/
baix/cars/certi/cates-of-con form ity/en_GB/
index.html General no
tes
29
29

Inf
Inf
or
ormation on t
mation on t he REAC
he REACH rH regulation
egulation
EU and EFT
EU and EFT A countr
A countries only:
ies onl y:
th e REACH regulation (Regulation (EC) No.
1907/2006, Article 33) stipula tes a duty tosup-
ply information about subs tances of very high
conce rn(SVHCs).
Me rcedes‑Benz AGacts tothe best of its kno wl-
edge toprev ent these SVHCs from being used
and toenable customers tosafely handle these
substances. There are SVHCs known to
Mercedes‑Benz AG, according tosupplier informa-
tion and internal product information, found in
individual components of this vehicle in quantities
of ove r 0.1 percent byweight.
Fu rther information can be obtained at thefo llo w-
ing addresses:
R https://reach.daimler.com/de/home/
R https://reach.daimler.com/en/home/ N
No
ot
tes f
es f or per
or per sons wit
sons wit h electr
h electronic medical aids
onic medical aids
Mercedes-Benz AGcannot, despite carefully
de veloping vehicle systems, comple tely rule out th
e interaction of vehicle systems with elect ronic
medical aids such as ca rdiac pacemake rs.
In addition, there are components installed in the
ve hicle that, rega rdless of the operating status of
th eve hicle, can generate magnetic /elds on a par
with permanent magnets. These /elds can be
fo und, forex ample, in the area around the multi-
media and sound system or also in the area of the
seats, depending on theve hicle equipment.
Fo rth is reason, thefo llowing can occur in isolated
cases, depending on the aids used:
R Medical aids malfunctioning
R Adve rse health e.ects
Obser vethe no tes and warnings of the manufac-
turer of the medical aids; if in doubt, contact the
device manufacturer and/or your doctor. If there
is continuing uncer tainty concerning the possibil-
ity of medical aids malfunctioning, Mercedes-
Benz AGrecommends using only fewelectrical
ve hicle systems and/or main taining a distance
from the components.
Plug-in h
Plug-in h ybr ybrid
id When
charging the high-voltage batter y,ke ep a
distance of at least an arm's length between the
medical aid and thefo llowing components:
R the po wer supply equipment
This includes charging stations in thefo rm of a
wa llbox or a public charging point, forex am-
ple.
R vehicle components car rying live voltage
This includes thech arging cable and the
ch arging cont rol box, forex ample.
Only ha verepairs and maintenance workinthe
area of thefo llowing components car ried out at a
qu ali/ed specialist workshop:
R vehicle components car rying live voltage
R transmission aerials
R multimedia system and sound system
If yo u ha veany queries or suggestions, consult a
qu ali/ed specialist workshop. Gene
ral no tes
41
41

R
R
es
estr traint syst
aint syst em functionality
em functionality When
theve hicle is switched on, a self-test is per-
fo rm ed, during which the6 restraint system
wa rning lamp lights up. It goes out no later than a
few seconds aTer theve hicle is star ted. The com-
ponents of there straint system are then func-
tional. Malfunctioning r
Malfunctioning r
es
estr traint syst
aint syst em
em A malfunction has occur
red in there straint sys-
te m if:
R the6 restraint system warning lamp does
not light up when theve hicle is switched on
R the6 restraint system warning lamp lights
up continuously or repeatedly during a journey
All v
All v ehicles, ex
ehicles, excep
cep t plug-in h
t plug-in h ybr
ybrid:
id: &
W
WARNING
ARNING Risk of injury due tomalfunc-
tions in there straint system
Co mp onents in there straint system ma y be
acti vated unintentionally or not deploy as
intended in an accident. #
Have there straint system checked and
re paired immediately at a quali/ed spe-
cialist workshop. Plug-in h
Plug-in h
ybr
ybrid:
id: &
D
DAN
AN GER
GER Risk of fatal injuries due to
re straint system malfunctions
Co mp onents in there straint system ma y be
acti vated unintentionally or not deploy as plan-
ned in an accident. In theeve nt of an acci-
dent, the high-voltage on-board electrical sys-
te m may not be deactivated as intended.
Yo u may su.er an electric shock if youto uch
th e damaged components of the high-voltage
on-board electrical system. #
Have there straint system checked and
re paired immediately at a quali/ed spe-
cialist workshop. #
ATer an accident, switch o. theve hicle
immediatel y. F
F
unction of t
unction of t he r
he res
estrtraint syst
aint syst em in an accident
em in an accident How
there straint system works is de term ined by
th e se verity of the impact de tected and the type
of accident anticipated:
R Frontal impact
R Rear impact
R Side impact
R Only for cer tain countries: rollo ver
The activation thre sholds forth e components of
th ere straint system are de term ined based on the
ev aluation of the sensor values measured at vari-
ous points in theve hicle. This process is pre-e mp-
tive in nature. The triggering/deployment of the
components of there straint system must take
place in good time at the start of the collision.
Fa ctors which can only be seen and measured
aTer a collision has occur red do not play a deci-
sive role in the deployment of an airbag. Nor do
th ey prov ide an indication of airbag deployment.
The vehicle may be deformed signi/cantly without
an airbag being deplo yed. This is the case if only
parts which are relatively easily deformed are
a.ec tedand thera te of vehicle deceleration is Occupant saf
ety
47
47

#
T To unloc o unloc k t
k the v
he v ehicle:
ehicle: touch the inner sur face
of the door handle. #
T To loc o loc k t
k the v
he v ehicle:
ehicle: touch sensor sur face 1
or 2. #
Conv Conv enience closing:
enience closing: touch recessed sensor
sur face 2 until the closing process has been
comple ted. %
Further information on con venience closing
(/ page 94).
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 loc k 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 83). #
Check the battery using the indicator lamp
(/ page 82). #
Replace theke y batter y,if necessary
(/ page 84). #
Use there placement key. #
Use the emer gency keyto lock or unlock
(/ page 89). #
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. 88
88
Opening and closing

Seats
Seats
A
A
djus
djusting t ting t he fr
he front seat mec
ont seat mec hanicall
hanically (wit
y (without
hout
Seat Comf
Seat Comf or
ort P
t P ack
ack ag
age)
e) &
W
WARNING
ARNING Risk of becoming trapped if the
seats are adjusted bychildren
Children could become trapped if they adjust
th e seats, particular lywhen unat tended. #
When leaving theve hicle, alw aysta ke the
ke y with you and lock theve hicle. #
Never lea vechildren unattended in the
ve hicle. &
W
W ARNING
ARNING Risk of becoming trapped dur-
ing seat adjustment
When you adjust a seat, you or other vehicle
occupants could become trapped, e.g. on the
seat guide rail. #
Make sure when adjusting a seat that no
one has any body parts in the sweep of
th e seat. Obser
vethe saf ety no tes on "Airbags" and "Chil-
dren in theve hicle". &
W
WARNING
ARNING Risk of accident due tothe
driver's seat not being engaged
The driver's seat may mo veunexpectedly
while driving.
This could cause youto lose control of the
ve hicle. #
Always make sure that the driver's seat
is engaged before starting theve hicle. &
W WARNING
ARNING Risk of accident due toadjust-
ing theve hicle settings while theve hicle is
in motion
Yo u could lose control of theve hicle in thefo l-
lowing situations in particular:
R ifyo u adjust the driver's seat, the head
re straint, the steering wheel or the mir ror
while theve hicle is in motion
R ifyo ufa sten your seat belt while theve hi-
cle is in motion #
Before starting theve hicle: in particular,
adjust the driver's seat, head restraint,
stee ring wheel and mir ror,and fasten
yo ur seat belt. &
W
WARNING
ARNING Risk of becoming trapped if the
seat height is adjusted carelessly
If yo u adjust the seat height carelessl y,yo u or
ot her vehicle occupants could be trapped and
th ereby injured.
Children in particular could accidentally press
th e electrical seat adjustment buttons and
become trapped. #
While moving the seats, make sure that
hands or other body parts do not get
under the le ver assembly ofthe seat
adjustment system. Seats and st
owing
103 103

&
W
WARNI NG
ARNI NGRisk of accident due toadjust-
ing theve hicle settings while theve hicle is
in motion
Yo u could lose control of theve hicle in thefo l-
lowing situations in particular:
R ifyo u adjust the driver's seat, the head
re straint, the steering wheel or the mir ror
while theve hicle is in motion
R ifyo ufa sten your seat belt while theve hi-
cle is in motion #
Before starting theve hicle: in particular,
adjust the driver's seat, head restraint,
stee ring wheel and mir ror,and fasten
yo ur seat belt. &
W
WARNING
ARNING Risk of becoming trapped if the
seat height is adjusted carelessly
If yo u adjust the seat height carelessl y,yo u or
ot her vehicle occupants could be trapped and
th ereby injured. Children in particular could accidentally press
th
e electrical seat adjustment buttons and
become trapped. #
While moving the seats, make sure that
hands or other body parts do not get
under the le ver assembly ofthe seat
adjustment system. &
W WARNING
ARNING Risk of injury due tohead
re straints not being /tted or being adjus-
te d incor rectly
If head restraints ha venot been installed or
ha ve not been adjusted cor rectl y,there is an
increased risk of injury in the head and neck
area, e.g. in theeve nt of an accident or when
braking. #
Always drive with the head restraints /t-
te d. #
Before driving o., make sure forev ery
ve hicle occupant that the centre of the
head restraint supports the back of the
head at about eye le vel. &
W
WARNING
ARNING Risk of injury or death due to
incor rect seat position
The seat belt will not o.er the intended le vel
of pr otection if you ha venot mo vedth e seat
backrest toan almost vertical position.
In particular, you may slip under the seatbelt
and injure yourself. #
Adjust the seat proper lybefore begin-
ning your journe y. #
Always ensu rethat the seat backrest is
in an almost vertical position and that
th e shoulder section of your seat belt is
ro uted across the centre of your shoul-
der. &
W
WARNING
ARNING Risk of injury due toexcessive
st ra in on thegr ab handle
If yo u apply your full body weight tothegr ab
handle or pull it abruptl y,thegr ab handle may
be damaged or become loose from its anchor-
age. 106 106
Seats and st
owing