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

&
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

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

%
V
Vehicles wit
ehicles wit h a tyr
h a tyre pr
e pressur
essur e loss w
e loss w ar
arning
ning
syst
syst em:
em: if an emer gency spa rewheel is /tted,
th e tyre pressure loss warning system cannot
function reliabl y.Only restart the system
again when the emer gency spa rewheel has
been replaced with a new wheel.
V
V ehicles wit
ehicles wit h a tyr
h a tyre pr
e pressur
essur e monit
e monit or
oring sy
ing sy s-
s-
t
t em:
em: if an emer gency spa rewheel is /tted, the
tyre pressure monitoring system cannot func-
tion reliabl y.Fo r a few minutes aTer an emer-
ge ncy spa rewheel is /tted, the system may
still display the tyre pressure of there mo ved
wheel. Only restart the system again when the
emer gency spa rewheel has been replaced
with a new wheel.
Be sure toalso obser vethefo llowing fur ther rela-
te d subjects:
R Notes on tyre pressure (/ page 375)
R Tyre pressure table (/ page 376)
R Notes on /tting tyres (/ page 379)
R Fitting an emer gency spa rewheel
(/ page 383) In0ating
In0ating
t
the emerg
he emerg ency spar
ency spar e wheel
e wheel *
N
NOOTE
TE Overheating due tothe tyre in0ation
compressor running too long #
Do not runth e tyre in0ation compressor
fo r longer than ten minutes without inter-
ru ption. R
R
eq
eq uir
uir ements:
ements:
The emer gency spa rewheel has been /tted cor-
re ctl y. ( / page 383)
Comply with the manufacturer's saf ety no tes on
th e stic ker of the emer gency spa rewheel and on
th e tyre in0ation compressor. #
Remo vethe stic ker with the label 80 km/h
from the tyre in0ation compressor housing
and a1x it tothe inst rument cluster within the
driver's /eld of vision. #
Remo vethe tyre in0ation compressor from the
st ow age space under the luggage compart-
ment 0oor . (/ page 356, 355) #
Pull /ller hose 1and plug 3out of the tyre
in0ation compressor housing. #
Insert plug 7of /ller hose 1inthe soc ket
on the tyre in0ation compressor and then turn
it until plug 7engages. #
Unscr ewthe cap from theva lve on the emer-
ge ncy spa rewheel. #
Screw union nut 2of /ller hose 1onto the
va lve. #
Make sure on and o. switch 4ofthe tyre
in0ation compressor is set to 00. #
Insert plug 3in a soc ket in your vehicle.
R Cigar ette lighter soc ket 390
390
Wheels and tyres

Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/consequences and uences and0050
0050Solutions
Solutions
Place the key in the
marked space See Owner's
Manual *K
eydetection is malfunctioning. #
Change the location of theke y in theve hicle. #
Place theke y in the slot for starting the engine with theke y (/ page 170). Lights Lights
Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/conseq uences and
uences and0050
0050Solutions
Solutions
:
Left dipped beam (examp le) *T
he cor responding light source is defecti ve. #
Drive on carefull y. #
Consult a quali/ed specialist workshop immediatel y.
or #
Check whe ther you are permitted toreplace the light source yourself (/ page 148).
% LED light sources: the display message forth e cor responding light appears only when all the light-emitting diodes
in the light are faulty. Display message
s andwarning/indicator lamps
419
419

Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/consequences and uences and0050
0050Solutions
Solutions
:
Malfunction See Owner's
Manual *T
heexterior lighting is malfunctioning. #
Consult a quali/ed specialist workshop.
*V Vehicles wit ehicles wit h a tr
h a trailer hitc
ailer hitc h:
h:a fuse may ha veblown. #
Stop theve hicle in accordance with the tra1c conditions. #
Check the fuses and replace them if necessary (/ page 371).
:
Automatic driving lights
inoperative *T
he light sensor for automatic driving lights is malfunctioning. #
Consult a quali/ed specialist workshop.
:
Active Light System inoper-
ative *T
he active headlamps are malfunctioning. #
Consult a quali/ed specialist workshop. 420 420
Displ
aymessages and warning/indicator lamps

Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/consequences and uences and0050
0050Solutions
Solutions
:
Switch on headlamps *Y
ou are driving without lo w-beam headlamps. #
Turn the light switch tothe0058 or0058 position.
:
Switch off lights *Y
ou are leaving theve hicle and the lights are still switched on. #
Turn the light switch tothe0058 position.
:
Intelligent Light System
inoperative *T
he Intelli gent Light System is malfunctioning. The lighting system continues tofunction proper lywithout the functions
of the Intelligent Light System. #
Consult a quali/ed specialist workshop.
Adaptive Highbeam Assist
currently unavailable See
Owner's Manual *A
daptive Highbeam Assist is tempo rarilyuna vailable.
The system limits ha vebeen reached (/ page 143).
Once the cause of the problem is no longer present, the system will be available again. The Adaptive Highbeam
Assist available again displaymessage will appear. #
Drive on Display messages and
warning/indicator lamps
421
421

Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/consequences and uences and0050
0050Solutions
Solutions
Ù
Steering malfunction See
Owner's Manual *T
he elect ric steering lock is malfunctioning. The steering may be loc kedby the electric steering loc k. &
W WARNI NG
ARNI NGRisk of accident if steering capability is impai red
If th e steering does not function as intended, theve hicle's operating saf ety is jeopardised. #
Pull over and stop theve hicle safely as soon as possible, paying attention toroad and tra1c conditions. Do
not continue driving under any circums tances. #
Consult a quali/ed speciali stwo rkshop. #
Stop theve hicle immediately in accordance with the tra1c conditions. Do not continue driving. #
Consult a quali/ed specialist workshop.
û
Before starting the engine,
turn the steering wheel. *T
he elect ric steering lock could not unlock the steering. #
Switch o. theve hicle. #
Tounlock the steering, mo vethe steering wheel slightly tothe leT and right. #
Switch on theve hicle again.
Active bonnet malfunction
See Owner's Manual *T
he active bonn et(pedest rian pr otection) is malfunctioning or inoperative aTer having already been triggered. #
Consult a quali/ed specialist workshop. Displ
aymessages and warning/indicator lamps
435 435

Dr
Dr
iving safe
iving safe ty syst
ty systems
ems Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/consequences and uences and0050
0050Solutions
Solutions
0025
00E5
currently unavailable See
Owner's Manual *
ABS and ESP ®
are temp orarily una vailable.
Other driving systems and driving saf ety systems (e.g. BAS) may also be temp orarily una vailable.
The brake system will continue tooperate normall y.Braking distance may inc rease in an emer gency braking situation. &
W WARNI NG
ARNI NGRisk of skidding if ABS and ESP ®
are malfunctioning
The wheels may lock during braking and ESP ®
does not per form any vehicle stabilisation.
The steerability and braking characteristics are heavily impaired and the braking distance may increase. In addi-
tion, other driving saf ety sy stems are swit ched o.. #
Drive carefully on a suitable str etch of road, making slight steering mo vements at a speed abo ve30 km/h. #
Ifth e display message does not disappear, consult a quali/ed specialist workshop immediatel y.Drive care-
full y. 462
462
Display message
s andwarning/indicator lamps

Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/consequences and uences and0050
0050Solutions
Solutions
0025
00E5
inoperative See Owner's
Manual *
ABS and ESP ®
are malfunctioning.
Other driving systems and driving saf ety sy stems (e.g. BAS) ma y also be malfunctioning.
The brake sy stem will continue tooperate normall y.Braking distance may inc rease in an emer gency braking situation. &
W WARNI NG
ARNI NGRisk of skidding if ABS and ESP ®
are malfunctioning
The wheels may block during braking and ESP ®
does not per form any vehicle stabilization.
The steerability and braking characteristics are heavily impaired and the braking distance may increase. In addi-
tion, other driving saf ety sy stems are swit ched o.. #
Drive on carefull y. #
Have ABS and ESP ®
ch ecked immediately at a quali/ed specialist workshop. 00E5
currently unavailable See
Owner's Manual *
ESP ®
is temp orarily una vailable.
Other driving systems and driving saf ety sy stems (e.g. BAS) ma y also be malfunctioning. &
W WARNING
ARNING Risk of skidding if ESP is malfunctioning ®
If ESP ®
is malfunctioning, ESP ®
cann otcar ryout vehicle stabilisation. In addition, other driving saf ety sy stems are
swit ched o.. #
Drive carefully on a suitable str etch of road, making slight steering mo vements at a speed abo ve30 km/h. Display message
s andwarning/indicator lamps
463
463

W
W
ar
ar ning and indicat
ning and indicat or lam
or lamps
ps Ov
Ov
er
ervie
vie w of indicat
w of indicat or and w
or and war
arning lam
ning lam ps
ps Some systems will per
form a self-test when the
ve hicle is switched on. Some indicator and warn-
ing lamps may brie0y light up or 0ash. This beha v-
iour is non-critical. These indicator and warning
lamps indicate a malfunction only if they light up
or 0as haTer theve hicle has been star ted or dur-
ing a journe y.
S
S t
tandar
andar d ins
d instr
trument displ ay
ument display W
W
idescr
idescr een coc
een coc kpit ins
kpit instrtrument display
ument display Depending on
the display setting, the positions of
th e indicator lamps on the inst rument display may
di.er from theex ample shown.
Indicat
Indicat or and w
or and w ar
arning lam
ning lam ps:
ps:
0075 Restraint system (/ page 480)
00E9 Seat belt (/ page 480)
_ Reduced po wer (/ page 482)
00D6 System error (/ page 482)
003D Electricalfault (/ page 482)
ï Trailer hitch (/ page 483)
Ù Powe r steering (/ page 483) ÿ
V
V ehicles wit
ehicles wit h a widescr
h a widescr een coc
een cockpit
kpit:
:
coolant temp erature (/ page 484)
00B9 Engine diagnostics (/ page 484)
0028 V
Vehicles wit
ehicles wit h a diesel engine:
h a diesel engine: preglow
003D Electricalfault (/ page 484)
00D4 Reser vefuel wi thfuel /ller 0ap loca-
tion indicator (/ page 484)
0024 Electric parking brake (red)
(/page 488)
0024 Electric parking brake (yellow)
(/page 488)
004D Brakes (yellow) (/ page 488)
004D Brakes (red) (/ page 488)
L Distancewarning (/ page 490)
Ó Active Brake Assist (/ page 490)
ê Active Brake Assist (/ page 490)
0025 ABS (/page 491)
00E5 ESP®
(/ page 491)
00BB ESP®
OFF (/ page 491) Display messages and
warning/indicator lamps
479 479