2021 MERCEDES-BENZ B-CLASS HATCHBACK check engine light

#
Remo vetheke y1 from theke yring. #
Place theke y1 inthe mar ked space 2on
th e symbol 3.
The vehicle will start aTer a short time.
When youre mo vetheke y1 from the mar ked
space 2,theve hicle can be driven. For fur-
th er engine starts ho wever,theke y1 must
be located in the mar ked space 2onthe
symbol 3during the entire journe y. #
Have theke y1 checked at a quali/ed spe-
cialist workshop.
If t
If t he v
he v ehicle does no
ehicle does no t st
t st art:
art: #
Place theke y1 inthe mar ked space 2and
lea veitth ere. #
V
Vehicles wit
ehicles wit h manual tr
h manual tr ansmission:
ansmission: Depress
th e clutch pedal. #
Depress the brake pedal and start theve hicle
using the start/s top button.
% You can switch on the po wer supply or the
ve hicle with the start/s top button. Obser
veany information rega rding display mes-
sages that can be displ ayed on the inst rument
displa y. S
S
t
tar
ar ting t
ting t he v
he vehicle via R
ehicle via R emot
emote Online Ser
e Online Ser vices
vices Cooling or heating t
Cooling or heating t
he v
he vehicle int
ehicle int er
erior bef
ior bef ore
ore
st
st ar
ar ting t
ting t he jour
he jour ney
ney
Ensu rethefo llowing before starting the engine:
R The legal stipulations in the area where your
ve hicle is par ked allow engine starting via
smartphone.
R It is safe tostart and runth e engine where
yo ur vehicle is par ked.
R The fuel tank is su1cient lyfull.
R The star ter battery is su1ciently charge d.
Char
Char ging t
ging t he st
he start
arter batt
er batt er
ery bef
y bef or
ore st
e st ar
arting t
ting t he
he
jour
jour ney
ney
Yo u can receive a message on your smartphone
when the state of charge ofthe star ter battery is
lo w. You can then start theve hicle with the smart-
phone tocharge the batter y.The vehicle is auto-
matically switched o. aTer ten minutes. Ensure
thefo llowing before starting the engine:
R The legal stipulations in the area where your
ve hicle is par ked allow engine starting via
smartphone.
R It is safe tostart and runth e engine where
yo ur vehicle is par ked.
R The fuel tank is su1cient lyfull.
S
S t
tar
ar ting t
ting t he v
he vehicle (R
ehicle (R emot
emot e Online)
e Online) &
W
WARNING
ARNING Risk of crushing or entrapment
due tounintentional starting of the engine
Limbs could be crushed or trapped if the
engine is star ted unintentionally during service
or maintenance work. #
Always secure the engine against unin-
te ntional starting before ca rrying out
main tenance or repair work. R
R
eq
eq uir
uir ements:
ements:
R Park position 005Dis selected.
R The anti-theT alarm system is not activated.
R The hazard warning light system is switched
o.. Driving and parking
171
171

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 336). 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 337).
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
337
337

#
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. 340
340
Maintenance and care

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

006F
2nd seat row, right Not loc ked...... 437
003D 12 V battery See Owner's Man-
ual......................................................... 467
ò Acoustic presence indicator
inoperative............................................ .426
: Active Light System inoperative..... 420
0099 AdBlue system fault Emer. op.:
max. XXX km/h Start not poss. in
XXX km.................................................. 476
0099 AdBlue system fault Emer gency
op. in XXX miles See Owner's Manual.... 475
0099 AdBlue system fault Engine
start not possible................................... 476
0099 AdBlue system fault See Own-
er's Manual............................................ 475
00B3 Add 1 litre engine oil when next
re fuelling ............................................... 477
é ATTENTION ASSIST inoperati ve..... 451
é ATTENTION ASSIS T:Take a
break!.................................................... 451 :
Automatic driving lights inoper-
ative...................................................... 420
00D7 Battery overheated Stop, every-
body out! Outdoors if possible ................ 428
û Before starting the engine, turn
th e steering wheel.................................. 435
004D Brake immediately ........................ 450
Á Change key batteries .................... 417
00E5 Charger cable connected .............. 426
004D Check brake 0uid le vel.................. 450
ï Check trailer hitch lock (white
display message) .................................... 432
0077 Check tyre(s) ................................ 470
003A Clean the fuel /lter....................... 440
ÿ Coolant Stop vehicle Switch
engine o............................................... 439
0025 currently una vailable See Own-
er's Manual............................................4 62
00E5 currently una vailable See Own-
er's Manual............................................4 6300B3
Engine oil le vel cannot be meas-
ured....................................................... 478
00B3 Engine oil le velRe duce oil le vel..... 477
00B3 Engine oil le velSt op vehicle
Switch engine o.................................... 477
00B3 Engine oil pressure Stop Switch
o. engine.............................................. 478
ä Fault Drive at max. 80 km/h ......... 461
0075 Front leT malfunction Consult
wo rkshop (e xample)...............................4 14
003B inoperative Battery low................. 423
003B inoperative Char geHV battery...... 424
003B inoperati veHigh-voltage battery
ch arging inco mplete ............................... 424
003B inoperative Refuel vehicle............. .424
003B inoperative See Owner's Man........ 423
0025 inoperative See Owner's Manual.. .463
00E5 inoperative See Owner's Manual.. .464
007A inoperative See Owner's Manual.. .465
0053 Inoperative................................... 466 Index
503 503