engine overheat MERCEDES-BENZ B-CLASS HATCHBACK 2021 Owners Manual

&
D
DAN
AN GER
GER Risk of fatal injury due topoison-
ous exhaust gases
If th eta ilpipe is bloc ked or su1cient ventila-
tion is not possible, poisonous exhaust gases
such as carbon monoxide may enter theve hi-
cle. This is the case if theve hicle gets stuck in
sno w,forex ample. #
Keep theta ilpipe and the area around
th eve hicle free from snow when the
ve hicle or the stationary heater is run-
ning. #
Open a wind owonthe side of theve hicle
fa cing away from the wind toensure an
adequate supply of fresh air. &
W
WARNING
ARNING Risk of accident due tothe
brake system overheating
If yo u lea veyour foot on the brake pedal when
driving, the brake system may overheat.
This increases the braking distance and the
brake system can even fail. #
Never use the brake pedal as a foot re st. #
Do not depress the brake pedal and the
accelerator pedal at the same time while
driving. *
N
NOOTE
TE Engine damage due toexcessively
high engine speeds The engine will be damaged if
you drive with
th e engine in theove rrev ving range. #
Do not drive with the engine in theove r-
re vving range. *
N
NOOTE
TE Causing wearto the brake linings by
permanently depressing the brake pedal #
Do not permanently depress the brake
pedal while driving. #
Touse braking e.ect of the engine, shiT
to a lo werge ar in good time. *
N
NOOTE
TE Damage tothe driv etra in and
engine when pulling away #
Do not warm upthe engine while the
ve hicle is stationar y.Pull away immedi-
atel y. #
Avoid high engine speeds and driving at
full thro ttle until the engine has reached
its operating temp erature. *
N
NOOTE
TE Damage tothe catalytic con verter
due tonon-combusted fuel The engine is not
running smoo thly and is mis-
/ring.
Non-combus ted fuel may getinto the catalytic
con verter. #
Only depress the accelerator pedal
slightl y. #
Have the cause recti/ed immediately at
a qu ali/ed specialist workshop. 174 174
Driving and parking

#
Before refuelling, switch o. theve hicle
and, if /tted, the stationary heater and
ke ep switched o. during /lling. &
W
WARNING
ARNING Risk of injury from fuels
Fu els are poisonous and hazardous toyour
health. #
Do not swallow fuel or let it come into
contact with skin, eyes or clo thing. #
Do not inhale fuel vapour. #
Keep children away from fuel. #
Keep doors and windo wsclosed during
th ere fuelling process.
If yo u or other people come into contact with
fuel, obser vethefo llowing: #
Immediate lyrinse fuel o. your skin with
soap and water. #
If fuel comes into contact with your eyes,
immediately rinse them thoroughly with
clean water. Seek medical at tention
immedia tely. #
Ifyo u swallow fuel, seek medical atten-
tion immediatel y.Do not induce vomit-
ing. #
Change immediately out of clo thing that
has come into contact with fuel. &
W WARNING
ARNING Risk of /re and explosion due
to electrostatic charge
Electrostatic charge can ignite fuel vapour. #
Before you open the fuel /ller cap or
ta ke hold of the pump nozzle, touch the
me tallic vehicle body. #
Toavo id creating ano ther electrostatic
ch arge , do not get into theve hicle again
during there fuelling process. &
W
WARNING
ARNING Risk of /re from fuel mixture
Ve hicles with a diesel engine:
If yo u mix diesel fuel with petrol, the 0ash
point of the fuel mixture is lo werth an that of
pure diesel fuel. While
theve hicle is running, component parts
in theex haust system may overheat without
wa rning. #
Neverre fuel using petrol. #
Never mix petrol with diesel fuel. *
N
NOOTE
TE Damage caused bythe wrong fuel Ve
hicles with a petrol engine:
Even small amounts of the wrong fuel could
re sult in damage tothe fuel system, the
engine and the emission control system. #
Only refuel using unleaded, sulphu r-free
spar k-ignition engine fuel that conforms
to European EN 228, or an equivalent
speci/cation.
Fu el of this speci/cation may contain up to
10% ethanol. Your vehicle is suitable for use
with E10 fuel.
Ne verre fuel wi thone of thefo llowing fuels:
R Diesel 192 192
Driving and parking

Se
Se
tting A
tting A TTENTION ASSI ST
TTENTION ASSIST
Multimedia system:
4 © 5
Settings 5
Assistance
5 Attention Assist
Se
Se tting op
tting op tions
tions #
Select Standard ,Sensitive orOff .
Sugg
Sugg es
esting a rting a r es
est art ar ea
ea #
Select Suggest rest area .#
Activate or deactivate the function.
If AT TENTION ASSIST de tects fatigue or
increasing lack of attention, it suggests a rest
area in the vicinity. #
Select the suggested rest area.
Yo u are guided tothe selected rest area. Cr
Cr
uise contr
uise control and limit ol and limit er
er F
F
unction of cr
unction of cr uise contr
uise controlol
Cruise control regula testh e speed totheva lue
selected bythe driver.
If yo u accelerate toove rtake, forex ample, the
stored speed is not dele ted. If youre mo veyour fo
ot from the accelerator pedal aTer overtaking,
cruise cont rol will resume speed regulation back
to the stored speed.
Yo u can store any speed abo ve20 km/h up tothe
maximum design speed or up tothe set winter
tyre limit.
Obser vethe no tes on driving systems and your
re sponsibility; you may otherwise failto recognise
dangers (/ page 223).
Display Display s in t
s in the Ins
he Ins tr
trument Display
ument Display
R h (gre y): cruise control is selected but not
yet activated.
R h (gre en): cruise control is active.
A stored speed appears along with theh dis-
pla y.
% The segments extending from the cur rent
stored speed tothe end of the scale, or tothe
set winter tyre limit, light up in the speedome-
te r. Syst Syst
em limits em limits
Cruise control may be unable tomaintain the
stored speed on uphill gradients. The stored
speed is resumed when thegr adient evens out.
Change into a lo werge ar in good time on long and
steep downhill gradients. Take particular no teof
th is when driving a laden vehicle. By doing so, you
will make use of the engine's braking e.ect. This
re lie vesth e load on the brake system and pre-
ve nts the brakes from overheating and wearing
to oqu ickl y.
Do not use cruise control in thefo llowing situa-
tions:
R in tra1c situations which requ ire frequent
ch anges of speed, e.g. in heavy tra1c, on
winding roads
R on slippery roads. Accelerating can cause the
drive wheels tolose traction and theve hicle
could then skid.
R when visibility is poor
F
F unction of t
unction of t he limit
he limiter
er
The limiter restricts the speed of theve hicle. To
re duce the speed tothe set speed, the limiter
applies the brakes automaticall y.232
232
Driving and parking

Coolant
Coolant
N
No
ot
tes on coolant
es on coolant
Obser vethe no tes on operating 0uids
(/ page 396). &
W
WARNING
ARNING Risk of /re‑ and injury from
antif reeze
If antifreeze comes into contact with hot com-
ponent parts in the engine compartment, it
may ignite. #
Allow the engine tocool down before
yo uto p up the antifreeze. #
Make sure that no antif reeze spills out
next tothe /ller opening. #
Thoroughly clean the antifreeze from
component parts before starting the
ve hicle. *
N
NOOTE
TE Damage caused byincor rect cool-
ant #
Only use coolant that has been premixed
with there qu ired antifreeze pr otection. Information on coolant is
available at thefo l-
lowing locations:
R Inthe Mercedes-Benz Speci/cation for
Operating Fluids 320.1
- Athttps://be vo.mercedes-benz.com
- Inthe Mercedes-Benz BeVo App
R Ataqu ali/ed specialist workshop *
N NOOTE
TE Overheating at high outside temp er-
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 396). &
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. 404
404
Te
ch nical data

Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/consequences and uences and0050
0050Solutions
Solutions #
Refuel immedia tely.
Subse quentl y,there may be temp orary restrictions in theav ailability of elect ric mode over a driving distance of
50 km.
If th ere is fuel in theve hicle, there is a fault with the combustion engine. #
Consult a quali/ed specialist workshop.
"Electric" drive program
currently unavailable *T
hecharge leve l of the high-voltage battery is not su1cient forth e Electric drive prog ram.
Char gethe high-voltage battery (/ page 198).
Reduced drive system per-
formance See Owner's
Manual *T
he drive system switches toemer gency ope ration mode due toa malfunction. #
Drive on carefull y. #
Consult a quali/ed specialist workshop.
00D7
Battery overheated Stop,
everybody out! Outdoors if
possible *T
he high- voltage battery has overheated. There is a risk of /re. #
Stop theve hicle immediately in accordance with the tra1c conditions. #
If possible, stop theve hicle in the open air and ensure that all vehicle occupants getout.
% Supporting vehicle functions may activate automaticall y,e.g. the air-recirculation mode as part of climate control. #
Do not continue driving. #
If smoke is present, lea vethe danger zone and call the /re service immediatel y. #
Consult a quali/ed specialist workshop even if there are no extern al signs of a /re. 428 428
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
00BD
Top up coolant See Own-
er’s Manual *T
he coolant le vel is too lo w.
* N
N O OTE
TE Engine damage due toinsu1cient coolant #
Avoid long journe yswith insu1cient coolant. #
Add coolant (/ page 342). #
Have the engine cooling system checked at a quali/ed specialist workshop.
ÿ
Coolant Stop vehicle
Switch engine off *T
he coolant is too hot. #
Stop immediately in accordance with the tra1c conditions and switch o. theve hicle. &
W WARNING
ARNING Risk of burns when opening the bonnet
If yo u open the bonnet in theev ent of an overheated engine or /re in the engine compartment, thefo llowing situa-
tions may occur:
R You may come into contact with hot gases.
R You may come into contact with other escaping hot operating 0uids. #
Before opening the bonnet, allow the engine tocool down. #
Intheev ent of a /re in the engine compartment, keep the bonnet closed and call the /re service. #
Wait until the engine has cooled down. Display messages and
warning/indicator lamps
439
439

Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/consequences and uences and0050
0050Solutions
Solutions
0080
Trans. oil overheated Drive
on with care *T
he transmission is overheating. When the display message is active, start-up and driving characteristics may be tem-
porarily impaired. #
Drive at low engine speed. #
Avoid sporty driving. #
Before pulling away on uphill gradients, let the transmission cool down until the display message disappears.
Parking lock inoperative
Apply the parking brake *T
he transmission is malfunctioning. The park position 005Dcann otbe selected. #
Park theve hicle safel y. #
Use the electric parking brake tosecure theve hicle against rollingaway.
Teaching in transmission
Operate selector lever
Brake for XX seconds Risk
of vehicle rolling *T
he transmission is being taught in. There is a risk of theve hicle rolling away. #
Depress and hold the brake pedal until thete ach-in process has been comple ted.
The electric parking brake is applied automatically during thete ach-in process. #
Switch on theve hicle. #
Select park position 005D, transmission position 005Eor neutral 005C.
Risk of vehicle rolling away
Apply parking brake See
Owner's Manual *T
he transmission position cann otbe reliably identi/ed. #
Use the electric parking brake tosecure theve hicle against rollingaway.
Teaching in transmission
complete *T
he transmission's teach-in process is comple te. All transmission positions can be selected again. 444 444
Display messages and
warning/indicator lamps

Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/consequences and uences and0050
0050Solutions
Solutions
Transmission Malfunction
Visit workshop *T
he transmission is malfunctioning.
Consult a quali/ed specialist workshop.
Depress clutch fully to
start engine *Y
ou ha veattem pted tostart theve hicle without depressing the clutch pedal. #
Depress the clutch pedal and then start theve hicle.
*T hevehicle has stalled while theve hicle was pulling away,e.g. because the clutch pedal wasre leased tooqu ickl y. #
Depress the clutch pedal again.
The vehicle will start automaticall y. #
Slowly re leasethe clutch pedal topull away.
Clutch overheated Avoid
pulling away until the warn-
ing goes out *T
he clut chis under considerable load and is overheating.
Av oid frequent pulling away and driving at walking pace over longer distances. #
Stop theve hicle, paying attention toroad and tra1c conditions and lea vetheve hicle running.
The clutch will cool more quickly when theve hicle is running.
or #
If possible, continue driving at a steady speed and remo veyour foot from the clutch pedal. Do not let the clutch
drag.
The clutch will cool while theve hicle is in motion.
When the clutch has cooled down, the display message will disappear.
Auxiliary battery malfunc-
tion (white display message) *T
he auxiliary battery forth e automatic transmission is no longer being charge d. #
Consult a quali/ed specialist workshop. Displ
aymessages and warning/indicator lamps
445 445

W
W
ar
ar ning/indicat
ning/indicat or lampP
or lam pP ossible causes/conseq
ossible causes/consequences and uences and0050
0050Solutions
Solutions
R The engine coolant pump is faulty
If th ere is an additional warning tone, the coolant temp erature has exceeded 120°C. &
W
WARNING
ARNING Risk of burns when opening the bonnet
If yo u open the bonnet in theeve nt of an overheated engine or /re in the engine compartment, thefo llowing situa-
tions may occur:
R You may come into contact with hot gases.
R You may come into contact with other escaping hot operating 0uids. #
Before opening the bonnet, allow the engine tocool down. #
Intheev ent of a /re in the engine compartment, keep the bonnet closed and call the /re service. #
Stop immediately in accordance with the tra1c conditions and switch o. theve hicle. Do not continue driving. #
Notethe messages on the instrument displa y.
If t If t he coolant t
he coolant t em
em per
per atur
atur e displa
e displa y is at t
y is at the low
he lower end of t
er end of t he t
he tem
emper
per atur
atur e scale:
e scale: #
Consult a quali/ed specialist workshop.
If t
If t he coolant t he coolant t em
emper
per atur
atur e displa
e displa y is at t
y is at the upper end of t
he upper end of t he t
he tem
emper
per atur
atur e scale:
e scale: #
Exit theve hicle and keep a safe distance from it until the engine has cooled down. #
Check the coolant le vel (/ page 342). Display message
s andwarning/indicator lamps
485
485

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