warning light MERCEDES-BENZ A-CLASS HATCHBACK 2021 Repair Manual

Switc
Switc
hing t
hing t he r
he reading light on and
eading light on and o.
o.#
Brie0y mo vea hand up or down beneath the
inside rearview mir ror.
The reading light is switched on or o. forthe
driver or the front passenger. Switc
Switc hing t
hing t he searc
he searc h light on and
h light on and o.
o. #
T
T o switc
o switc h on:
h on:reach across the front
passenger seat with a hand.
The sear chlight is switched on forth e driver. #
T
T o switc o switc h
ho.:
o.: take a hand back away from the
front passenger seat.
The search light is switched o. again. Inf
Inf
or
ormation on
mation on pr
pro/les,
o/les, t
themes, sugg
hemes, sugg es
estions andtions and
fav
fav our
our it
ites
es Fo
r electrically adjustable seats obser vethefo l-
lowing no tes. &
W
WARNING
ARNING Risk of becoming trapped dur-
ing adjustment of the driver's seat aTer
calling up a driver pro/le
Selecting a user pro/le may trigger an adjust-
ment of the driver's seat tothe position sa ved
under the user pro/le. You or other vehicle
occupants could be injured in the process. #
Make sure that when the position of the
driver's seat is being adjus ted via the
multimedia system, no people or body
parts are in the seat's range of mo ve-
ment.
If th ere is a risk of someone becoming trap-
ped, stop the adjustment process immedi-
atel y: #
a)Tapth ewa rning message onthe
media displa y.
or #
b) Press a memory function position but-
ton or a seat adjustment switch on the
driver's door.
The adjustment process will be stopped. 292 292
MBUX multimedia system

#
Select Maximum ,8 amps or6 amps .
When the battery is charge d, thech arging cur-
re nt is limi tedto the selected amperage.
% For saf etyre asons, only use thech arging
cable supplied with theve hicle or an original
Mercedes-Benz charging cable. Mercedes-
Benz thoroughly tests these original charging
cables forth eir suitability forth e high-voltage
ch arging of your vehicle. Pur chase these parts
from your Mercedes-Benz Service Centre and
obtain advice there.
A
A ctiv
ctiv ating or deactiv
ating or deactiv ating r
ating rout
oute-based oper
e-based oper ating
ating
mode s
mode str trat
at egy
egy #
Select Electric in city .
Depending on the pr evious status, the func-
tion is activated or deactivated. Calling up t Calling up t
he ener
he ener gy
gy0ow
0ow display
display Multimedia system:
4 © 5
EQ #
Select Energy flow.
The visualisation of the energy 0ow in theve hi-
cle is displ ayed. In addition
tothe energy 0o w,information on the
status of thehy brid system and the cur rent state
of charge ofthe high-voltage battery is also dis-
pla yed. F F
unctions of t
unctions of t he ener
he energy
gy0ow
0ow display
display 1
State of charge ofthe high-voltage battery
2 Combustion engine
3 Energy 0ow
4 High-voltage battery
5 Status of thero ute-based operating-mode
strategy (/ page 177) The active components of
thehy brid system are
highlighted in the energy 0ow displa y.The energy
0ow between the individual components is shown
in colour.
The energy 0ow is shown in di.erent colours
depending on the operating status:
R Whit Whit e: e:constant energy 0ow
R R
Red:
ed: high energy 0ow (boost e.ect)
R Gr
Green:
een: low- emission energy 0ow in the case of
re cuperation, elect ric mode and when charg-
ing the high-voltage battery N
N
a
avig
vig ation
ation N
No
ot
tes on na
es on na vig
vigation
ation R
R
out
out e guidance wit
e guidance wit h augment
h augmented r
ed reality
eality &
W
WARNING
ARNING Risk of accident and injury as a
re sult of distraction, inco rrect depiction or
wrong interpr etation of the display
The camera image of the augmented reality
displ ayis not suitable as a guide for driving. MBUX multimedia system
299
299

Then,
you can select a service and be connected
to a specialist at the Mercedes-Benz Customer
Centre.
Calling t Calling t he Mer
he Mercedes-Benz Cust
cedes-Benz Cust omer Centr
omer Centre
eaTer
aTer
aut
aut omatic accident or br
omatic accident or br eakdo
eakdown det
wn det ection
ection
R
R eq
eq uir
uir ements:
ements:
R The vehicle has de tected an accident or break-
down situation.
R The vehicle is stationar y.
R The hazard warning lights are switched on.
% This function is not available in all countries.
The vehicle can de tect accident or breakdown sit-
uations under cer tain circumstances.
In theev ent an accident or breakdown is de tec-
te d, the emer gency guide sh ows saf ety no tes in
th e multimedia system displa y.
ATer quitting the emer gency guide display on the
multimedia system, a prom ptappears asking
whe ther youwo uld like toget support from the
Mercedes-Benz Customer Centre. #
Select Call.
R ATer your ag reement, or if the Mercedes
me connect service "Accident and Break-
down Management" is active, theve hicle
data is transfer red automatically
(/ page 316).
R The Mercedes-Benz Customer Centre
ta ke syo ur call and or ganises the break-
down and accident assistance.
Yo u may be charge dfo rth ese services.
% Depending on the se verity of the accident, an
automatic emer gency call can be initia ted.
This has priority over all other active calls.
% In addition, if the Mercedes me connect
service "Telediagnostics" is active, a similar
prom ptcan appear aTer a delay in theev ent
of a breakdown. If you are already in contact
with the Mercedes-Benz Customer Centre or
ha ve already received support, this prom pt
can be ignored or declined.
% Ifyo u answer the prom ptfor support from the
Mercedes-Benz Customer Centre with Later,
th e message will be hidden and appear again
later. The prom
pttriggered bythe Mercedes me
connect service "Telediagnostics", can either
be con/ rmed or declined. ATer being
declined, this will not be shown again.
Arr Arr anging a ser
anging a ser vice appointment via a Mer
vice appointment via a Mer cedes
cedes
me call
me call
If yo u ha veactivated the maintenance manage-
ment service, releva nt vehicle data is transfer red
automatically tothe Mercedes-Benz Customer
Centre. You will then receive individual recom-
mendations rega rding the maintenance of your
ve hicle.
Re gardless of whe ther you ha veconsen tedto the
maintenance management service, the multime-
dia system reminds you aTer a cer tain amount of
time that a service is due. A prom ptappears ask-
ing if youwo uld like tomake an appointment. #
T To arr
o arr ang
ange a ser
e a ser vice appointment
vice appointment: :select Call.
ATer your ag reement, theve hicle data is
transfer red and the Mercedes-Benz customer
centre take syo ur prefer red appointment date.
The information is then sent toyour desired
service outlet. MBUX multimedia system
313
313

R
Frequent operation in mountainous terrain or
on poor road sur faces
R When the engine is oTen leT idling for long
periods
R Operation in particular lydusty conditions
and/or if air-recirculation mode is frequently
used
In these or similar operating conditions, ha vethe
interior air /lter, air /lter, engine oil and oil /lter,
fo rex ample, changed more frequentl y.The tyres
must be checked more frequently if theve hicle is
operated under increased loads. Further informa-
tion can be obtained at a quali/ed specialist work-
shop. Batt Batt
er
ery disconnection per
y disconnection per iods
iodsThe AS
SYST PLUS service inter val display can cal-
culate the service due date only when the battery
is connected. #
Display and no tedown the service due date
on the inst rument display before disconnect-
ing the battery (/ page 330). Engine com
Engine com
par
partment
tment A
A
ctiv
ctiv e bonne
e bonne t (pedes
t (pedestr trian pr ot
ian pr otection)
ection) Oper
Oper
ation of t
ation of t he activ
he active bonne
e bonne t (pedes
t (pedestr trian pr ot
ian pr otec-
ec-
tion)
tion)
In cer tain accident situations, the actuation of the
active bonnet reduces therisk of injury topedes-
trians. The rear area of the bonnet is raised by
appr oximately 70 mm.
Fo rth e drive tothewo rkshop, reset the actuated
active bonnet yourself (/ page 331).
ATer the active bonnet has been actuated, pedes-
trian pr otection may be limited.
Ha ve the full functionality of the active bonnet
re stored in a quali/ed specialist workshop.
R
R ese ese tting t
tting t he activ
he activ e bonnet
e bonnet &
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. #
With your hand 0at, push down active bonnet
1 inthe area around the hinges on bo th
sides (ar rows ).
In doing so, the actuator is depressurised and
yo u may hear a hissing sound.
The engine bonnet must engage in position. #
Ifth e active bonnet can be raised slightly at
th ere ar in the area of the hinges, repeat the
step until it engages co rrectl y. Maintenance and ca
re
331
331

#
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. 334
334
Maintenance and care

Ext
Ext
er
erior lighting
ior lighting
R Clean the lenses with a wet sponge and mild
cleaning agent, e.g. car sha mpoo.
R Only use cleaning agents or cleaning clo ths
th at are suitable for plastic lenses.
V
V ehicle soc ke
ehicle soc ket (high-v
t (high-v olt
oltag
age batt
e batt er
ery)
y)
R Use clean water and a soT clo thtoclean the
ve hicle soc ket.
R Do not use high-pressure cleaners or cleaning
agents, such as soap.
Sensors
Sensors
R Clean the sensors in the front and rear bump-
ers with a soT clo thand car shampoo
(/ page 220).
R When using a high-pressure cleaner, main tain
a minimum distance of 30 cm.
Rev Rev er
ersing camer
sing camer a and 360° Camera
a and 360° Camera
R Open the camera co ver with the multimedia
system (/ page 260).
R Use clean water and a soT clo thtoclean the
camera lens.
R Do not use a high-pressure cleane r.T
T
ailpipes
ailpipes
R Clean with a cleaning agent recommended for
Mercedes-Benz, especially in the winter and
aTer washing theve hicle.
R Do not use acidic cleaning agents.
Tr
Tr ailer hitch
ailer hitch
R Obser vethe no tes on care in the trailer hitch
manufacturer's operator manual.
R Do not clean the ball neck with a high-pres-
sure cleaner or sol vent.
R Remo vetraces of rust on the ball, forex ample,
with a wire brush.
R Remo vedirt with a lint-free clo th.
R ATer cleaning, lightly oil or grease the ball
head.
% Before using trailers with anti-torsional cou-
pling, obser vethe manufacturer's operator
manual. N No
ot
tes on car
es on car e of t
e of t he int
he int er
erior
ior &
W
WARNING
ARNING Risk of injury from plastic parts
breaking o. aTer the use of sol vent-based
ca re products
Care and cleaning products containing sol-
ve nts can cause sur faces in the cockpit to
become porous. When the airbags are
deplo yed, plastic parts may break away. #
Do not use any care or cleaning products
containing sol vents toclean the cockpit. &
W WARNING
ARNING Risk of injury or fatal injuries
from bleached seat belts
Bleaching or dyeing seat belts can se verely
we aken them.
This can, forex ample, cause seat belts to tear
or fail in an accident. #
Never bleach or dye seat belts. To
avo id damage totheve hicle, obser vethefo l-
lowing no tes on cleaning and care: Main
tenance and ca re
343
343

#
Obser vethe sequence described for
connecting and disconnecting the jump
leads when receiving starting assistance. #
Do not connect or disconnect the bat-
te ry term inals while the engine is run-
ning. &
W
WARNI NG
ARNI NGRisk of explosion due toexplo-
sive mixture of gases
An explosive mixture of gases can escape
from the battery during charging and starting
assis tance. #
Fire , naked 0ames, smoking and creating
spar ksmust be avoided. #
Make sure there is adequate ventilation. #
Do not stand overth e batter y. &
W
WARNI 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 instrument
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. 356 356
Breakdown assistance

sumer on
your ow nve hicle, e.g. there ar win-
dow heater or lighting.
When the starting assistance/charging process is
comple te: #
Firs t, re mo vethe jump lead/charging cable
from ear thpoint 3and the negative pole of
th e donor batter y,then from positive clamp
2 and the positive pole of the donor batter y.
Begin ea chtime with the contacts on your
ow nve hicle /rst. #
ATer removing the jump lead/charging cable,
close co ver1 of positive clamp 2.
Plug-in h
Plug-in h ybr
ybrid:
id:ifyo ur vehicle has been star ted
with starting assis tance, it may not be possible to
use the electric drive for appr oximately 30
minutes.
Fu rther information can be obtained at a quali/ed
specialist workshop. R R
eplacing t
eplacing t he 12 V batt
he 12 V batt ery
ery #
Obser vethe no tes on the 12 V battery
(/ page 354). Mercedes-Benz
recommends that you ha vethe
12 V battery replaced at a quali/ed specialist
wo rkshop, e.g. at a Mercedes-Benz Se rvice
Centre.
Obser vethefo llowing no tes if youwa nttoreplace
th e battery yourself:
R Alwaysre place a faulty battery with a battery
which meets the speci/c vehicle requ ire-
ments.
The vehicle is equipped with a 0eece batter y.
Fu llve hicle functionality is only guaranteed
with a 0eece batter y.Fo r saf etyre asons,
Mercedes-Benz recommends that you only
use batteries which ha vebeen tested and
appro vedfo ryo ur vehicle byMercedes-Benz.
R Use de tach able parts such as vent hoses,
elbow /ttings or term inal co vers from the bat-
te ry which is tobe replaced.
R Make sure that theve nt hose is alw ays con-
nected tothe original opening on the side of
th e batter y.
Fi t any existing or supplied cell caps.
Otherwise, gases or battery acid could
escape. R
Make sure that de tach able parts are recon-
nected in the same way. T T
o
o w
w -st
-st ar
arting or to
ting or towing away
wing away P
P
er
er mitt
mitt edto
ed towing met
wing met hods (non plug-in h
hods (non plug-in h ybr
ybrid)
id) Mercedes-Benz
recommends transporting your
ve hicle in the case of a breakdown, rather than
to wing it away.
Fo rto wing, use a tow rope or tow bar with bo th
axles on thegr ound. Do not use tow bar systems. &
W
WARNING
ARNING Risk of accident when towing
with steering wheel lock
If th e steering wheel lock is engaged, you will
not be able tosteer theve hicle. #
When towing with a tow rope or tow bar,
alw ays switch on theve hicle. *
N NOOTE TE Damage totheve hicle due to tow-
ing awa y incor rectly #
Obser vethe inst ructions and no tes on
to wing away. 358 358
Breakdown assistance

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 370).
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. 370
370
Wheels and tyres

-
Athttps://be vo.mercedes-benz.com
- Inthe Mercedes-Benz BeVo App
R Ataqu ali/ed specialist workshop *
N
NOOTE
TE Overheating at high outside tempe r-
atures If an inappropriate coolant is used,
the engine
cooling system is not su1ciently pr otected
against overheating and cor rosion at high out-
side temp eratures. #
Only use coolant appr ovedby Mercedes-
Benz. #
Obser vethe inst ructions in the
Mercedes-Benz Speci/cations for Oper-
ating Fluids 320.1. Ha
ve the coolant regula rly re placed at a quali/ed
specialist workshop.
Proportion of antif reeze concentrate in the engine
cooling system:
R A minimum of 50% (antifreeze pr otection down
to about -37°C) R
A maximum of 55% (antif reeze pr otection
down to-45°C) N
No ot
tes on windscr
es on windscr een w
een washer
asher 0uid
0uid Obser
vethe no tes on operating 0uids
(/ page 393). &
W
WARNING
ARNING ‑ Risk of /re and injury due to
windscreen washer concent rate
Wi ndsc reen washer concent rate is highly 0am-
mable. It could ignite if it comes into contact
with hot engine component parts or the
ex haust system. #
Make sure that no windscreen washer
concent rate spills out next tothe /ller
opening. *
N NOOTE
TE Damage totheex terior lighting due
to unsuitable windscreen washer 0uid Unsuitable windscreen
washer 0uids may
damage the plastic sur face of theex terior
lighting. #
Only use windscreen washer 0uids which
are also suitable for use on plastic sur fa-
ces, e.g. MB SummerFit or MB WinterFit. *
N
NOOTE
TE Bloc ked spr aynozzles caused by
mixing windscreen washer 0uids #
Do not mix MB SummerFit and MB Win-
te rFit with other windscreen washer 0u-
ids. Do not use distilled or de-ionised
water. Other-
wise, the /ll le vel sensor may be triggered er rone-
ous ly.
Re commended windscreen washer 0uid:
R abo vefreezing point: e.g. MB SummerFit
R below freezing point: e.g. MB WinterFit
Fo rth e cor rect mixing ratio, referto the informa-
tion on the antifreeze container.
Mix washer 0uid with windscreen washer 0uid all
ye ar round. 402
402
Te
ch nical data