brake sensor MERCEDES-BENZ A-CLASS HATCHBACK 2021 User Guide

*
N
NO
OTE
TE Damage from automatic braking If one of
thefo llowing functions is switched
on, theve hicle brakes automatically in cer tain
situations:
R Active Brake Assist
R Active Distance Assist DISTRONIC
R HOLD function
R Active Parking Assist
To avoid damage totheve hicle, deactivate
th ese systems in thefo llowing or similar situa-
tions: #
during towing #
in a car wash *
N
NOOTE
TE Damage due tounsuitable car wash #
Before driving into a car wash make sure
th at the car wash is suitable forth eve hi-
cle dimensions. #
Ensu rethere is su1cient ground clear-
ance between the underbody and the
guide rails of the car wash. #
Ensure that the clearance width of the
car wash, in particular the width of the
guide rails, is su1cient. To
avo id damage toyour vehicle when using a car
wa sh, ensu rethefo llowing beforehand:
R Active Distance Assist DISTRONIC is deactiva-
te d.
R The HOLD function is switched o..
R The 360° Camera or there ve rsing camera is
switched o..
R The side windo wsand sliding sunroof are com-
ple tely closed.
R The blo werfo rth eve ntilation/heating is
switched o..
R The windsc reen wiper switch is in position g.
R The key is at a minimum dis tance of 3 m away
from theve hicle. Otherwise theta ilgate could
open unintentionall y. R
In automatic car washes with con veyo r sys-
te ms:
- Neutral iis engaged.
- V
V ehicles wit
ehicles wit h aut
h automatic tr
omatic tr ansmission:
ansmission: If
yo uwo uld like tolea vetheve hicle while it
is being washed, make sure theke y is
located in theve hicle. The park position
j isotherwise automatically engaged.
% If, aTer the car wash, youre mo vethewax
from the windscreen and wiper rubbers, this
will pr event smearing and reduce wiper noise.
A
A ut
ut omatic car w
omatic car w ash mode
ash mode
In car wash mode, theve hicle is prepared for driv-
ing into the automatic car wash. Car wash mode
can be activated at a speed of up to20 km/h
Ac tivate (/ page 339).
The following settings are made when car wash
mode is activated:
R The outside mir rors are folded in.
R Topreve ntthe windscreen washer system
from starting up automaticall y,thera in sensor
is deactivated.
R The rear wind owwiper is deacti vated. 338
338
Maintenance and care

R
Furthermore, the use of cer tain tyre types in
cer tain regions and areas of operation can be
high lybene/cial.
R Only use tyres and wheels of the same type
(summer tyres, winter tyres, MOExtended
tyres) and the same make.
R Only /t wheels of the same size on one axle
(leT and right).
It is only permissible to/t a di.e rent wheel
size in theev ent of a 0at tyre in order todrive
to the specialist workshop.
R Do not make any modi/cations tothe brake
system, the wheels or the tyres.
The use of shims or brake dust shields is not
permitted and may in validate theve hicle's
ge neral ope rating permit.
R V
V ehicles wit
ehicles wit h a tyr h a tyre pr
e pressur
essur e monit
e monit or
or ing sy
ing sy s-
s-
t
t em:
em: all /t tedwheels must be equipped with
functioning sensors forth e tyre pressure mon-
itoring system.
R Attemp eratures below 7 °C use winter tyres
or all-season tyres mar kedi M+Sfor all
wheels. Wi
nter tyres pr ovide the best possible grip in
wintry road conditions.
R For M+S tyres, only use tyres with the same
tread.
R Obser vethe maximum permissible speed for
th e M+S tyres /t ted.
If th e tyre's maximum speed is below that of
th eve hicle, this must be indicated byan
appropriate label in the driver's /eld of vision.
R Run in new tyres at moderate speeds forthe
/r st 100 km.
R Replace the tyres aTer six years at the latest,
re ga rdless of wear.
R When r
When r eplacing wit
eplacing wit h tyr
h tyres t
es that do no
hat do no t f
t featur
eatur e
e
r
r un-0at
un-0at c
char
har act
act er
er is
istics:
tics: vehicles with
MOExtended tyres are not equipped with a
TIREFIT kit at thefa ctor y.Equip theve hicle
with a TIREFIT kit aTer replacing with tyres
th at do not feature run-0at characteristics,
e.g. winter tyres.
% You can permanently limit the maximum
speed for driving with winter tyres
(/ page 232). Fo
r more information on wheels and tyres, con-
ta ct a quali/ed specialist workshop.
Be sure toalso obser vethefo llowing fur ther rela-
te d subjects:
R Notes on tyre pressure (/ page 369)
R Tyre pressure table (/ page 370)
R Notes on the emer gency spa rewheel
(/ page 383) N
No
ot
tes on int
es on int erc
erchanging wheels
hanging wheels &
W
WARNING
ARNING Risk of injury thro ugh di.erent
wheel sizes
Inter changing the front and rear wheels can
se verely impair the driving characteristics.
The disk brakes or wheel suspension compo-
nents may also be damaged. #
Only inter change the front and rear
wheels if the wheels and tyres ha vethe
same dimensions. 376
376
Wheels and tyres

Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/consequences and uences andM
MSolutions
Solutions
¸
Ã
ç
Ä
temporarily unavailable
Sensors dirty *F
ront and corner radar sensors (hereaTer "sensors") are malfunctioning. Possible causes:
R The senso rsare dirty
R Heavy rain or snow
R Extended country driving without other tra1c, e.g. in the desert
Driving systems and driving saf ety sy stems ma y be malfunctioning or temp orarily una vailable. The brake system, steer-
ing and drive system will continue tofunction normall y. #
Drive on
Once the causes of the problem are no longer present, the driving systems and driving saf ety sy stems will be available
again and the cor responding symbols will be switched o..
If th e display message does not disappear: #
Stop theve hicle in accordance with the tra1c conditions. #
Clean all sensor co vers from outside (/ page 220). #
Restart theve hicle. 456 456
Displ
aymessages and warning/indicator lamps

Dr
Dr
iving syst
iving syst ems
ems W
W
ar
ar ning/indicat
ning/indicat or lampP
or lam pP ossible causes/conseq
ossible causes/consequences and uences andM
MSolutions
Solutions
L
Wa rning lamp for distance
wa rning function *T
he red distance warning lamp lights up while theve hicle is in motion.
The dis tance totheve hicle in front is too small forth e speed selected.
If th ere is an additional warning tone, you are approaching an obstacle at too high a speed. #
Be prepared tobrake immediatel y. #
Increase the distance.
Fu nction of Active Brake Assist (/ page 241).
Ó Ac tive Brake Assist warning
lamp *T
heActive Brake Assist warning lamp is on.
Due todirty sensors or a malfunction, the system is not available or thera nge of functions is restric ted. #
Notethe messages on the instrument displa y.
ê
Ac tive Brake Assist warning
lamp *T
heActive Brake Assist warning lamp is on.
The system is switched o. or thera nge of functions has been automatically restric ted.
This may be the case if the driver is not wearing a seat belt or ano ther driving system has been activated. #
Obser vethe no tes on Active Brake Assist (/ page 241). Display messages and
warning/indicator lamps
487
487

Br
Br
ak
ak es
es
ABS (Anti-lo ckBraking System).............. 221
Ac tive Brake Assist................................. 241
Ad aptive brake lights.............................. 226
BAS (Brake Assist System).................... .222
Driving tips............................................ 169
EBD (Electronic Brake forc e Distribu-
tion).......................................................2 24
HOLD function....................................... 225
Limited braking e.ect (salt-treated
ro ads)................................................... .169
Ne w/replaced brake linings/brake
discs...................................................... 168
Po st-collision brak e.................................. 61
Ru nning-in no tes.................................... 168
Br
Br ak ak es
es
see Recuperation
Br Br aking assist aking assist ance
ance
see BAS (Brake Assist System)
Br
Br eakdo
eakdo wn
wn
Assistance overview. ................................ 20
To w- starting........................................... 364
To wing away.......................................... 360
Tr anspo rting theve hicle........................ .362
Wheel chang e........................................ 378 Br
Br ea kdo
eakdo wn
wn
see Flat tyre
Butt
Butt ons
ons
St eering wheel....................................... 279 C
C
Calls
Calls Mercedes me......................................... 311
Camera
Camera
Information............................................ 220
Camera
Camera
see 360° Camera
see Dashcam
see Reversing camera
Car key
Car key
see Key
Car w Car w ash
ash
see Care
Car w
Car w ash (car
ash (car e)
e)............................................ 337
Car
Car -t
-to-X
o-X -Communication
-Communication
Displaying hazard warnings.................... 305
Care
Care 360° camera......................................... 342 Air-water duct........................................ 337
Au
tomatic car wash.............................. .337
Carpet................................................... 343
Decorative foil........................................ 341
Display................................................... 343
Exterior lighting...................................... 342
Head-up display..................................... 343
High-pressure cleaner............................3 39
Pa int...................................................... 340
Plastic trim............................................3 43
Re alwo od/trim elements..................... .343
Re versing camera..................................3 42
Ro of lining............................................. 343
Seat belt................................................ 343
Seat co ver............................................. 343
Sensors................................................. 342
St eering wheel....................................... 343
Ta ilpipes................................................ 342
Tr ailer hitc h............................................ 342
Ve hicle soc ketfo rth e high-voltage
battery................................................... 342
Wa shing byhand.................................... 340
Wheels/rims.......................................... 342
Wi ndo ws................................................ 342
Wi per blades.......................................... 342 496 496
Index

ç
suspended .................................... 449
: Switch o. lights............................ 418
: Switch on headlamps .................... 418
6 Tank is dep ressurised Ready for
re fuelling ............................................... 428
6 Tank ventilation Malfunction
Consult workshop ................................. .428
á temp orarily una vailable Camera
view restric ted....................................... 457
¸ temp orarily una vailable Sensors
dirty....................................................... 456
Ú Top up AdBlue Emer gency op. in
XXX miles See Owner's Manual.............. 471
+ Top up coolant See Owner ’s
Manual.................................................. 435
¥ Top up washer 0uid...................... .434
u Towing not permitted See Own-
er's Manual ............................................ 423
d Trans. oil overheated Drive on
with care................................................ 440 !
Turn on the ignition torelease
th e parking brake ................................... 446
Ú .................................................... 471
d Vehicle is operational Switch o.
ignition before exiting............................. 429
h Warning tyre defect....................... 468
h Wheel sensor(s) missing ................ 467
Ú XX,X l Top up AdBlue Swit chon
ignition, wait 60 sec. or eng. start not
poss...................................................... 472
"Electric" drive prog ram cur rently
una vailable............................................. 425
Ac tive Blind Spot Assist cur rently
una vailable See Owner's Manual ............ 454
Ac tive Blind Spot Assist inoperative........ 454
Ac tive Blind Spot Assist not available
when towing a trailer See Owner's
Manual.................................................. 455
Ac tive bonnet malfunction See Own-
er's Manual............................................ 432 Ac
tive Brake Assist Functions cur-
re ntly limi ted See Owner's Manual .........462
Ac tive Brake Assist Functions limited
See Owner's Manual.............................. 463
Ac tive Distance Assist available again ..... 451
Ac tive Distance Assist cur rently
una vailable See Owner's Manual ............ 450
Ac tive Distance Assist inoperative.......... 450
Ac tive Lane Keeping Assist cur rently
una vailable See Owner's Manual ............ 455
Ac tive Lane Keeping Assist inoperative... 455
Ac tive Steering Assist cur rently
una vailable due tomultiple emer-
ge ncy stops........................................... 452
Ac tive Steering Assist cur rently
una vailable See Owner's Manual ............ 452
Ac tive Steering Assist inoperative...........4 52
Ad aptive Highbeam Assist cur rently
una vailable See Owner's Manual ............ 418
Ad aptive Highbeam Assist inoperative ....4 19 502 502
Index

Only select
Park (P) when vehicle is
stationary.............................................. 438
Pa rking Assist and PARKTRONIC inop-
erative See Owner's Manual................... 458
Pa rking lock inoperative Apply the
parking brake ........................................ .440
Place theke y in the mar ked space
See Owner's Manual.............................. 416
PRE-SAFE inoperative See Owner's
Manual.................................................. 414
Re duce speed........................................ 469
Re duced drive system per form ance
See Owner's Manual.............................. 425
Re versing not poss. Consult workshop ... 439
Risk of vehicle rolling away App ly
parking brake See Owner's Manual ........ 441
Risk of vehicle rolling awayPa rking
brake not applied See Owner's Manual ... 446
Risk of vehicle rolling Driver door
open and transmission not in P .............. 439Ru
n Flat Indica tor inoperative................. 470
Speed limit (winter tyres) XXX km/h .......451
Speed Limit Assist cur rently una vaila-
ble See Owner's Manual........................ 451
Speed Limit Assist inoperative................ 451
Te aching in transmission comple te......... 441
Te aching in transmission Operate
selector le ver Brake for XX seconds
Risk of vehicle rolling ............................. 440
To shiT out of P or N,depress brake
and start engine.................................... .438
To switch o. the engine, press the
St art/ Stop button for at least 3 sec-
onds or 3 times...................................... 435
Tr a1c Sign Assist cur rently una vaila-
ble See Owner's Manual........................ 453
Tr a1c Sign Assist inoperative................. 453
Tr ansmission Malfunction ....................... 440
Tr ansmission Malfunction Stop............... 439 Tr
ansmission Malfunction Visit work-
shop ...................................................... 441
Ty re press. monitor cur rently una vaila-
ble......................................................... 466
Ty re press. monitor inoperative .............. 466
Ty re press. monitor inoperative No
wheel sensors ........................................ 467
Ty re pressure Check tyres ...................... 469
Ty re(s) ove rheated .................................. 469
Ve hicle not cur rently being charged
Charging station fault............................. 424
Wi per malfunctioning .............................434
Wi thout changing gear, consult work-
shop ............................................. .426, 439
Wi thout starting engine again, consult
wo rkshop ............................................... 426
Dist
Dist ance contr ance contr ol
ol
see Active Distance Assist DISTRONIC
DIS DIS TR TRONIC
ONIC
see Active Distance Assist DISTRONIC 504
504
Index

Door
Door
Additional door loc k................................. 86
Child saf ety lock (rear door )..................... 79
Locking/unlocking (emer gency key)........ .89
Opening (from inside).............................. .86
Unlo cking (from inside)............................ 86
Door contr
Door contr ol panel
ol panel......................................... 18
Dra
Dra wbar
wbar
see Tow- bar system
Dr
Dr iv
ive Awa
e Away Assi st
y Assi st........................................ .269
Dr
Dr iv
ive position
e position
Engaging................................................ 185
Dr
Dr iv
ive pr
e pr ogr
ogram display
am display .................................. 179
Dr
Dr iv
ive pr
e pr ogr
ograms
ams
see DYNAMIC SELECT
Dr
Dr iv
iver's seat
er's seat
see Seat
Dr
Dr iving abr
iving abr oad
oad
Light adjustment (l owbeam).................. 134
Dr
Dr iving safe
iving safe ty syst
ty system
em
ABS (Anti-lock Braking System)............. .221
Ac tive Brake Assist................................. 241
Ad aptive brake lights.............................. 226 BAS
(Brake Assist System).................... .222
Cameras................................................2 20
EBD (Electronic Brake forc e Distribu-
tion).......................................................2 24
ESP ®
Crosswind Assist.......................... 223
ESP ®
trailer stabilisation........................ 223
Overview................................................ 220
Ra dar and ultrasonic sensor s................. 220
Re sponsibility......................................... 219
ST EER CONTROL................................... 224
Dr Dr iving syst
iving syst em
em
Suspension with adaptive damping
adjustment............................................ 254
Dr
Dr iving syst
iving syst em
em
see 360° Camera
see Active Blind Spot Assist
see Active Distance Assist DISTRONIC
see Active Emer gency Stop Assist
see Active Lane Keeping Assist
see Active Parking Assist
see Active Speed Limit Assist
see Active Steering Assist
see ATTENTION ASSIST
see Blind Spot Assist
see Cruise cont rol see Driving saf
ety sy stem
see HOLD function
see Limi ter
see Parking Assist PARKTRONIC
see Reversing camera
see Speed Limit Assist
see Start-o. assist
see Tra1c Sign Assist
Dr
Dr iving tips iving tips
Driving abroad (low beam light adjust-
ment)..................................................... 134
Gene ral driving tips................................1 69
Ru nning-in no tes.................................... 168
Dr
Dr iving tips iving tips
see Recuperation
Dr ow
Dr ow siness det
siness det ection
ection
see ATTENTION ASSIST
Dynamic handling contr
Dynamic handling contr ol syst
ol system
em
see ESP ®
(Electronic Stability Prog ram)
D
D YN
YNAMIC SELECT AMIC SELECT
Ad aptive damping adjustmen t................254
Calling up the fuel consum ption indi-
cator...................................................... 181
Con/guring drive prog ram I................... .180 Index
505 505

V
V
ehicle dimensions
ehicle dimensions ...................................... 403
V
V ehicle emerg
ehicle emerg ency st
ency start
art...............................3 64
V
V ehicle
ehicle identi/cation
identi/cation number
number
see VIN
V
V ehicle
ehicle identi/cation
identi/cation plate
plate
EU type appr oval number....................... 392
Maximum gross vehicle weight............... 392
Pa int code............................................. 392
Pe rm issible axle load.............................. 392
VIN........................................................3 92
V
V ehicle int
ehicle int er
erior
ior
Cooling or heating (Remo teOnline)........ 167
V
V ehicle key
ehicle key
see Key
V
V ehicle maint
ehicle maint enance
enance
see ASS YST PLUS
V
V ehicle sensors
ehicle sensors
Information............................................ 220
V
V ehicle so cket
ehicle soc ket
Care...................................................... 342
Indicator lamps...................................... 201
V V ehicle t
ehicle t ool kit
ool kit
TIREFIT kit...................................... 349, 350 To
wing eye............................................. 363
V
V entilating
entilating
Con venience opening.............................. .94
V
V entilation
entilation
see Climate control
V
V ents
ents
see Air vents
VIN
VIN Engine compartment.............................. 392
Identi/cation pla te................................. 392
Wi ndsc reen............................................ 392
V
V ision
ision
Demisting windo ws................................ 155 W
W
W
W ar
ar ning lamp
ning lamp
see Warning/indicator lamp
W
W ar
ar ning syst
ning syst em
em
see ATA (anti-theT alarm system)
W
W ar
ar ning tr
ning tr iangle
iangle
Re moving............................................... 346
Setting up.............................................. 347 W
W
ar
ar ning/indicat
ning/indicat or lamp
or lamp
! ABSwarning lamp......................... 488
Ó Active Brake Assist warning lam p..4 87
J Brake system warning lamp (red)... 486
J Brake system warning lamp (yel-
low)....................................................... 485
ÿ Coolant warning lamp (red)........... 481
ÿ Coolant warning lamp (yellow).......4 83
! Electric parking brake indicator
lamp (red).............................................. 485
# Electrical fault warning lamp
...................................................... 480, 484
; Engine diagnosis warning lamp...... 483
å ESP®
OFF warning lam p................ 489
÷ ESP®
wa rning lamp 0ashes........... 488
÷ ESP®
wa rning lamp lights up......... 489
æ Fuelreser vewarning lamp lights
up.......................................................... 484
Ù Powe r steering warning lamp
(red)...................................................... 480 Index
525 525