check engine MERCEDES-BENZ A-CLASS SALOON 2021 User Guide

Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/consequences and uences andM
MSolutions
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 160). Lights Lights
Displa
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y messag es P
es Possible causes/conseq
ossible causes/conseq uences and
uences andM
MSolutions
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 140).
% LED light sources: the display message forth e cor responding light appears only when all the light-emitting diodes
in the light are faulty. 408
408
Display message
s andwarning/indicator lamps

Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/consequences and uences andM
MSolutions
Solutions #
Request service personnel from the operator of thech arging station via the emer gency call button attached tothe
ch arging station or the emer gency call numbers.
Vehicle not currently being
charged Charging station
fault *A
malfunction has occur red in thech arging station or the RFID card is not recognised. #
Start thech arging process at a di.erent charging station.
or #
Have the RFID card checkedto ensure it is functioning.
Charging method currently
unavailable Please try
again or change charging
method *A
temp orary malfunction has occur red in thech arging station. #
Wait until the malfunction has passed.
or #
Start thech arging process at a di.erent charging station.
Charging fault Please
change charging method
See Owner's Manual *A
temp orary malfunction has occur red in thech arging station. #
Wait until the malfunction has passed.
or #
Start thech arging process at a di.erent charging station.
Only electric drive availa-
ble Power limited *T
he fuel tank is em pty and the combustion engine is switched o.. The output of your vehicle is limi ted because you
are driving in elect ric mode. 416 416
Display messages and
warning/indicator lamps

V
V
ehicle
ehicle Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/conseq uences and
uences andM
MSolutions
Solutions
d
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 265). #
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. Display messages and
warning/indicator lamps
421
421

Engine
Engine
Displa
Displa
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es Possible causes/conseq
ossible causes/consequences and uences andM
MSolutions
Solutions
To switch off the engine,
press the Start/Stop but-
ton for at least 3 seconds
or 3 times. *Y
ou ha vepressed the start/s top button while theve hicle is in motion. #
Information about switching o. theve hicle while driving (/ page 160).
Cannot start engine See
Owner's Manual *T
hevehicle cann otbe star ted. #
Switch theve hicle o. and switch it back on #
Ifth e display message still appears, consult a quali/ed specialist workshop.
+
Top up coolant See Own-
er’s Manual *T
he coolant le vel is too lo w.
* N NO
OTE
TE Engine damage due toinsu1cient coolant #
Avoid long journe yswith insu1cient coolant. #
Add coolant (/ page 330). #
Have the engine cooling system checked at a quali/ed specialist workshop. Displ
aymessages and warning/indicator lamps
427
427

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es Possible causes/conseq
ossible causes/consequences and uences andM
MSolutions
Solutions
#
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
Displa
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y messag es P
es Possible causes/conseq
ossible causes/conseq uences and
uences andM
MSolutions
Solutions
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. 458
458
Displ
aymessages and warning/indicator lamps

Displa
Displa
y messag
y messag es P
es Possible causes/conseq
ossible causes/consequences and uences andM
MSolutions
Solutions #
Switch o. theve hicle. #
Add 1 l of engine oil (/ page 328). #
Check the engine oil le vel.
No tes on engine oil (/ page 391).
5
Engine oil pressure Stop
Switch off engine *T
he oil pressure is too lo w.
* N
N O OTE
TE Engine damage caused bydriving with insu1cient oil pressure #
Avoid driving with insu1cient oil pressure. #
Stop theve hicle immediately in accordance with the tra1c conditions. Do not continue driving. #
Switch o. theve hicle. #
Consult a quali/ed specialist workshop.
5
Engine oil level cannot be
measured *T
he elect rical connection tothe oil le vel sensor has been inter rupted or the oil le vel sensor is faulty. #
Consult a quali/ed speciali stwo rkshop. Displ
aymessages and warning/indicator lamps
467 467

W
W
ar
ar ning/indicat
ning/indicat or lampP
or lam pP ossible causes/conseq
ossible causes/consequences and uences andM
MSolutions
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
emper
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 330). 474
474
Display message
s andwarning/indicator lamps

W
W
ar
ar ning/indicat
ning/indicat or lampP
or lam pP ossible causes/conseq
ossible causes/consequences and uences andM
MSolutions
Solutions #
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.
; 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. Display messages and
warning/indicator lamps
475
475

Displa
Displa
y messag
y messag es
es
ç - - - km/h..................................... 441
È - - - km/h..................................... 441
h - - - km/h..................................... 440
# 12 V battery See Owner's Man-
ual......................................................... 456
ò Acoustic presence indicator
inoperative............................................ .415
: Active Light System inoperative..... 409
¯ AdBlue system fault Emer. op.:
max. XXX km/h Start not poss. in
XXX km.................................................. 465
¯ AdBlue system fault Emer gency
op. in XXX miles See Owner's Manual.... 464
¯ AdBlue system fault Engine
start not possible................................... 465
¯ AdBlue system fault See Own-
er's Manual............................................ 464
5 Add 1 litre engine oil when next
re fuelling ............................................... 466 é
ATTENTION ASSIST inoperati ve..... 440
é ATTENTION ASSIS T:Take a
break!.................................................... 440
: Automatic driving lights inoper-
ative...................................................... 409
Û Battery overheated Stop, every-
body out! Outdoors if possible ................ 417
û Before starting the engine, turn
th e steering wheel.................................. 424
J Brake immediately ........................ 438
Á Change key batteries .................... 406
è Charger cable connected .............. 415
J Check brake 0uid le vel.................. 439
ï Check trailer hitch lock (white
display message) .................................... 421
h Check tyre(s) ................................ 459
! Clean the fuel /lter....................... 429
ÿ Coolant Stop vehicle Switch
engine o............................................... 428 !
currently una vailable See Own-
er's Manual............................................4 51
÷ currently una vailable See Own-
er's Manual............................................4 52
5 Engine oil le vel cannot be meas-
ured....................................................... 467
5 Engine oil le velRe duce oil le vel..... 466
5 Engine oil le velSt op vehicle
Switch engine o.................................... 466
5 Engine oil pressure Stop Switch
o. engine.............................................. 467
ä Fault Drive at max. 80 km/h ......... 450
6 Front leT malfunction Consult
wo rkshop (e xample)...............................4 03
& inoperative Battery low................. 412
& inoperative Char geHV battery...... 413
& inoperati veHigh-voltage battery
ch arging inco mplete ............................... 413
& inoperative Refuel vehicle............. .413
& inoperative See Owner's Man........ 412 492 492
Index

Apply brake
toselect D or R ...................430
Apply brake toselect R .......................... 430
Au xiliary battery malfunction (red dis-
play message) ....................................... .434
Au xiliary battery malfunction (white
displ aymessage) .................................... 434
Beginning emer gency stop..................... 444
Blind Spot Assist cur rently una vailable
See Owner's Manual.............................. 445
Blind Spot Assist inoperative.................. 446
Blind Spot Assist not available when
to wing a trailer See Owner's Manual ...... 446
Cann otstart engine See Owner's
Manual................................................. .427
Charging fault Please change charging
me thod See Owner's Manual .................416
Charging me thod cur rently una vaila-
ble Please try again or change charg-
ing me thod............................................ 416 Check brake pads See Owner's Man-
ual........................................................
.439
Check tyre pressures then restart Run
Flat Indicator......................................... 462
Clutch overheated Avoid pulling away
until thewa rning goes out...................... 433
Cruise control and Limiter inoperative.... 440
Cruise control inoperative...................... 440
Cruise control o.................................... 441
Depress clutch fully tostart engine........ 433
Device de tected at diagnostics con-
nection See Owner's Manual................. .456
Drive system Malfunction Stop Switch
engine o............................................... 429
Drive system Malfunction Visit work-
shop ...................................................... 429
Fr ont-passenger airbag disabled See
Owner's Manual .................................... .404
Fr ont-passenger airbag enabled See
Owner's Manual .................................... .405 Hazard
warning lamps malfunctioning .... 412
Head-up display cur rently una vailable
See Owner's Manual.............................. 422
Head-up display inoperative ...................423
Limiter inoperative................................. 441
Limiter passive....................................... 441
N permanently active Risk of vehicle
ro lling....................................................4 31
Not possible tounlock charging cable
See Owner's Manual.............................. 415
Only elect ric drive available Power
limited................................................... 416
Only select Park (P) when vehicle is
stationary.............................................. 430
Pa rking Assist and PARKTRONIC inop-
erative See Owner's Manual................... 450
Pa rking lock inoperative Apply the
parking brake ........................................ .432
Place theke y in the mar ked space
See Owner's Manual.............................. 408 Index
495 495