battery MERCEDES-BENZ B-CLASS HATCHBACK 2021 Workshop Manual

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003B
Pre-entry climate control
(via key) available again
after engine start *Y
ou ha veattem pted toswitch on pre-ent ryclimate cont rol more than twice with theve hicle switched o.. #
Start theve hicle forte n seconds.
Pre-entry clima tecont rol is operational again.
003B Pre-entry climate control
(via key) inoperative HV-
battery low *T
hecharge ofthe high-voltage battery is too lo w.Pre-entry clima tecont rol cannot be switched on. #
Char gethe high-voltage batter y.
When the high-voltage battery is su1ciently charge d, pre-ent ryclimate cont rol will be operational again. Display message
s andwarning/indicator lamps
425 425

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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

V
V
ehicle
ehicle Displa
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0072
Vehicle is operational
Switch off ignition before
exiting *Y
ou are leaving theve hicle in a ready-to-drive state. #
Get out of theve hicle, secure it against rolling away and take theke y with you. #
Ifyo u do not lea vetheve hicle, switch o. the electrical consumers, e.g. the seat heating. Otherwise, the 12‑V bat-
te ry may dischar geand starting the engine may be possible only with the help of a second battery (jump start).
ï
Check trailer hitch
lock (white display message) *T
he trailer hitch is not operational during a jou rney with a trailer. &
W WARNING
ARNING Risk of an accident if the ball neck is not loc ked
The trailer may become de tach ed. #
Stop theve hicle immediately in accordance with the tra1c conditions. Do not continue driving. #
Uncouple the trailer and secure it against rolling away. #
Initiate a new swivelling procedu reand do not re-couple the trailer until the display message disappears. #
Initiate a new swivel mo vement (/ page 274). #
When the display message disappears, couple up the trailer and drive on.
If th e display message does not disappear, the trailer hitch is malfunctioning and the ball neck is not loc ked. 432
432
Display messages and
warning/indicator lamps

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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

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Until then, alw ays select park position 005Dmanually before you switch o. theve hicle. #
Before leaving theve hicle, apply the electric parking brake.
Auxiliary battery malfunc-
tion (red display message) *V
Vehicles wit ehicles wit h manual tr
h manual tr ansmission:
ansmission: There is afault with the auxiliary batter y.
V
V ehicles wit
ehicles wit h aut
h automatic tr
omatic tr ansmission:
ansmission: The auxiliary battery forth e transmission is no longer being charge d. #
Consult a quali/ed specialist workshop. #
V
Vehicles wit
ehicles wit h aut
h automatic tr
omatic tr ansmission:
ansmission: untilthen, alw ays select park position 005Dbefore you switch o. theve hicle. #
Before leaving theve hicle, apply the electric parking brake. Br
Br
ak
ak es
es Displa
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0024
Parking brake See Owner's
Manual *T
heyellow 0024 indicator lamp is lit. The electric parking brake is malfunctioning.
T
T o apply o apply :
: #
Switch theve hicle o. and switch it back on #
App lythe electric parking brake manually (/ page 221).
If it is not possible toapply the electric parking brake: #
Consult a quali/ed specialist workshop. #
Where necessar y,also secure the par kedve hicle against rolling away. 446
446
Display message
s andwarning/indicator lamps

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Device detected at diagnos-
tics connection See Own-
er's Manual *T
hevehicle functions forfa ult de tection are restric ted.
At least one of the main functions of the Mercedes me connect system is malfunctioning. #
Obser vethe no tes on the diagnostics connection (/ page 38). #
Consult a quali/ed specialist workshop. Batt Batt
ery
ery Displa
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003D
12 V battery See Owner's
Manual *T
hevehicle is o. and the state of charge ofthe 12 V battery is too lo w. #
Switch o. elect rical consume rsthat are not requ ired. #
Drive for 30–60 minutes.
or #
Char gethe 12 V battery when stationary (/ page 363).
*I fth e message appears while theve hicle is switched on, this indicates an on-board electrical system malfunction. #
Consult a quali/ed specialist workshop.
003D
See Owner's Manual *T
he 12 V battery is not being charge d. Display messages and
warning/indicator lamps
467 467

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* NO
NOTE
TEPossible engine damage if you continue driving #
Do not continue driving under any circumstances. #
Consult a quali/ed speciali stwo rkshop. #
Stop immediately in accordance with the tra1c conditions and switch o. theve hicle. #
Consult a quali/ed specialist workshop.
003D
Stop vehicle See Owner's
Manual *T
he 12 V battery is no lon ger being charge d and the state of charge istoo lo w.
* N
N O OTE
TE Possible engine damage if you continue driving #
Do not continue driving under any circumstances. #
Consult a quali/ed speciali stwo rkshop. #
Stop theve hicle immediately in accordance with the tra1c conditions. Do not continue driving. #
Switch o. theve hicle. #
Consult a quali/ed specialist workshop. 468
468
Displ
aymessages and warning/indicator lamps

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003D
Stop vehicle Leave engine
running *T
he 12 V battery charge leve l is too lo w. #
Stop theve hicle immediately in accordance with the tra1c conditions. Do not continue driving. #
Leavetheve hicle running #
Ifth e display message disappears: drive on. #
Ifth e display message does not disappear: consult a quali/ed specialist workshop. T T
yr
yr e pr
e pr essur
essur e monit
e monit or
or Displa
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Tyre press. monitor cur-
rently unavailable *T
here is inter fere nce from a po werful radio signal source. As a result, no signals from the tyre pressure sensors are
being received. The tyre pressure monitoring system is temp orarily una vailable.
The tyre pressure monitoring system will restart au tomatically as soon as the cause has been recti/ed. #
Drive on.
Tyre press. monitor inoper-
ative *T
he tyre pressure moni toring system is malfunctioning. &
W WARNI NG
ARNI NGThere is a risk of an accident if the tyre pressure monitoring system is malfunctioning
The tyre pressure monitoring system cannot issue a warning if there is pressure loss in one or more of the tyres.
Ty res with insu1cient tyre pressure may impair the driving characteristics as well as steering and braking. #
Have the tyre pressure monitoring system checked at a quali/ed specialist workshop. Displ
aymessages and warning/indicator lamps
469
469

W
W
ar
ar ning/indicat
ning/indicat or lampP
or lam pP ossible causes/conseq
ossible causes/consequences and uences and0050
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Make sure that the air supply tothera diator is not obstructed. #
Avoiding high loads on the engine, drive tothe nearest quali/ed specialist workshop. In doing so, ensu rethat the
coolant temp erature display remains below 120°C.
ÿ
Coolant warning lamp (yel-
low) *T
he yellow coolant warning lamp is lit while the engine is running.
Po ssible causes:
R The temp erature sensor is malfunctioning
R The charge air, transmission oil or battery cooling is faulty
R The radiator shutters are bloc ked or defective #
Avoiding high loads on the engine, drive tothe nearest quali/ed specialist workshop.
00B9 Engine diagnosis warning
lamp *T
he yellow engine diagnostics warning lamp is lit while the engine is running.
A malfunction has occur red in the engine, theex haust system or the fuel system.
The emissions limit value may ha vebeen exceeded and the engine may be running in eme rgency operation mode. #
Have theve hicle checked as soon as possible at a quali/ed specialist workshop.
V
V ehicles wit
ehicles wit h a diesel engine:
h a diesel engine: the fuel tank may ha vebeen run dr y. #
Start the engine thre eto four times aTer refuelling.
If th eye llow engine diagnosis warning lamp goes out, emer gency ope ration mode is cancelled. The vehicle need not
be checked. 486
486
Display messages and
warning/indicator lamps

Side airbag.............................................. 52
Wi ndow airbag......................................... 52
Air0 ow
Air0ow
Setting................................................... 157
Alar
Alar m syst
m syst em
em
see ATA (anti-theT alarm system)
All-wheel dr
All-wheel dr ive
ive
see 4M ATIC
Ambient lighting
Ambient lighting Setting (MBUX multimedia system)........ .146
Andr
Andr oid A
oid A uto
uto
see Smartphone integ ration
Animals
Animals Pets in theve hicle.................................... 80
Anti-loc
Anti-loc k br
k braking syst
aking syst em
em
see ABS (Anti-lock Braking System)
Anti-skid c
Anti-skid c hains
hains
see Sn owchains
Anti-t
Anti-theT heTprot
pr otection
ection
Ad ditional door loc k................................. 84
Immobiliser............................................ 102
Anti-t
Anti-theT heTprot
pr otection
ection
see ATA (anti-theT alarm system) Anticipat
Anticipat
or
ory occupant pr ot
y occupant pr otection
ection
see PRE-SAFE ®
(anticipatory occu-
pant pr otection)
see PRE-SAFE ®
PLUS (anticipatory
occupant pr otection plus)
Apple CarPlay
Apple CarPlay ®
®
see Smartphone integ ration
Assist
Assist ance syst
ance syst ems
ems
see Driving saf ety sy stem
ASS YS
ASS YST PL
T PL US
US
Battery disconnection period s................ 337
Displaying the service due dat e.............. 336
Fu nction/no tes...................................... 336
Re gular maintenance work..................... 336
Special service requ irements................. 336
AT
ATA A(anti-t
(anti-theT heTalar
alarm syst
m syst em)
em)
Deactivating the alarm........................... 103
Fu nction................................................ 102
Interior pr otection function.....................1 04
Priming/deactivating interior pr otec-
tion........................................................ 104
Priming/deactivating tow- awa y pro-
te ction................................................... 104
To w- awa y protection function................. 103 A
A TTENTION ASSIST
TTENTION ASSIST
Function................................................ 230
Setting.................................................. .232
System limitations.................................. 230
A
A tt
tt ention assist
ention assist ant
ant
see ATTENTION ASSIST
A A ut ut hor
hor ised w
ised w ork
orkshop
shop
see Quali/ed specialist workshop
A
A ut
ut omatic car w
omatic car w ash mode
ash mode
Ac tivating............................................... 345
A
A ut
ut omatic co-dr
omatic co-dr iv
iver airbag
er airbag shut
shuto.
o.
Fu nction of co-driver airbag shuto........... 55
A
A ut
ut omatic dist
omatic dist ance contr
ance control
ol
see Active Distance Assist DISTRONIC
A
A ut
ut omatic dr
omatic dr iving lights
iving lights ................................ 139
A
A ut
ut omatic engine st
omatic engine st art
art
see ECO start/stop function
A
A ut
ut omatic engine st
omatic engine st op
op
see ECO start/stop function
A
A ut
ut omatic fr
omatic fr ont passeng
ont passeng er airbag
er airbagshut
shut o.
o.
PA SSENGER AIR BAG indicator la mps...... 57
A
A ut
ut omatic measur
omatic measur es
esaTer
aTer an accident
an accident........... .60 Index
497
497