check engine light MERCEDES-BENZ A-CLASS SALOON 2021 Owners Manual

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 324). 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 325).
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
325
325

#
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. 328
328
Maintenance and care

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
Displa
y messag
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
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