check engine light MERCEDES-BENZ A-CLASS SALOON 2018 Owners Manual

#
Toswitch on the ignition: press button 1
twice.
The indicator lamps in the instrument clus ter
light up.
The ignition is switched off again if one of the
fo llowing conditions is me t:
R vehicles with automatic transmission:you
do not start theve hicle within 15minutes
and the transmission is in position jorthe
electric parking brake is applied.
R vehicles with manual transmission: you do
not start theve hicle within 15minutes and
th e electric parking brake is applied.
R you press but ton1 once. St
arting theve hicle St
arting theve hicle with thest art/s top but‐
ton
Requ irements:
R theke y is in theve hicle and is recognised. R
or: a Digi talVe hicle Key is located in the
mar ked space and is recognised
(/ page 156). #
Vehicles with manual transmission:
depress the clutch pedal. #
Vehicles with automatic transmission:
shift the transmission toposition jori. #
depress the brake pedal and press button 1
once. #
Ifth eve hicle does not star t:switch off non-
essential consumers and press button 1
once.
If th eve hicle still does not start, one of thefo l‐
lowing display messages appears in the multi‐
function display: #
Place the key in the marked space See Own-
er's Manual :st art theve hicle in emer gency
operation mode (/ page 157).
or #
Key not detected Place smartphone in charg-
ing bracket: place the mobile phone in the
mar ked space (/ page125). Yo
u can swit choff the engine while driving by
pressing button 1for about thre e seconds or
by pressing button 1thre e times within a sec‐
ond. Be sure toobser vethe saf ety no tes under
"Driving tips".
St arting theve hicle with a Digital Vehicle
Key
Re quirements:
R one of thefo llowing versions of the Digital
Ve hicle Key is available:
- suitable mobile phone
- Digital Vehicle Keyst icker
R theve hicle is equipped with the "Digital Vehi‐
cle Key" function.
R the "Digital Vehicle Key" function is activated
via Mercedes me connec t:http://
www.mercedes.me.
R the mobile phone is suf ficiently charge d.
% You can check the suitability of your mobile
phone byentering the phone number at
http://www.mercedes.me. 15 6
Driving and pa rking

#
Push yellow handle 1onthe bonn etcatch
to the left as far as it will go (palm down‐
wa rds). Lift the bonn etuntil it is automati‐
cally raised bythe pneumatic stru t. #
Toclose: lowe rth e bonn etand let it fall from
a height of appr oximately 20 cm. #
Ifth e bonn etcan still be lif ted slightl y,open
th e bonn etagain and close it with a little
fo rc e until it engages cor rectl y. Engine oil
Checking
the engine oil le vel using the on-
board compu ter
Re quirements:
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.
In order torecei veare sult as quickly as possi‐
ble:
R warm upthe engine
R park theve hicle on a le vel sur face
R leave the engine running at idling speed
On-board compu ter:
4 Service 5
Engine oil level
Yo u will see one of thefo llowing messages on
th e multifunction display:
R Engine oil level Measuring now : measure‐
ment of the oil le vel is not yet possible. #
Repeat there qu est af ter a maximum of
30 minutes driving. R
Engine oil level OK andthe bar display for
indicating the oil le vel on the multifunction
display is green and is between "min" and
"max": the 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 multifunc‐
tion display is orange and is below "min": #
Top up with 1 l engine oil.
R Reduce engine oil level andthe bar display
fo r indicating the oil le vel on the multifunc‐
tion display is orange and is abo ve"max": #
Drain off excess engine oil that has been
added. Consult a qualified specialist work‐
shop.
R For engine oil level turn on ignition: #
switch on the ignition tocheck the engine oil
le ve l.
R Engine oil level System inoperative : sensor
fa ulty or not inser ted. #
Consult a qualified specialist workshop.
R Engine oil level System currently unavail. : Maintenance and care
433

&
WARNING Risk ofexplosion from a fro‐
zen battery
A dischar ged battery may freeze at temp era‐
tures slightly abo veor below freezing point.
During starting assis tance or battery charg‐
ing, bat tery gas may be released. #
Alw aysth aw a frozen bat tery out first
before charging it or per form ing start‐
ing assis tance. If
th e indicator/warning lamps in the instrument
clus ter do not light up at low temp eratures, it is
ve ry likely that the dischar ged battery has fro‐
zen. In this case you may neither jump-s tart the
ve hicle nor charge the batter y.
The service life of a battery that has been
th awe d may be dramatically shor tened. The
st arting characteristics may be impaired, espe‐
cially at low temp eratures.
It is recommended that you ha veathaw ed bat‐
te ry checked at a qualified specialist workshop. *
NO
TEDama gecaused bynumerous or
ex tended attem ptsto start the engine Nume
rous or extended attem ptsto start the
engine may damage the catalytic con verter
due tonon-combu sted fuel. #
Avoid numerous and extended attem pts
to start the engine. Obser
vethefo llowing points during starting
assis tance and when charging the battery:
R Only use undamaged jump lead/charging
cables with a suf ficient cross-section and
insula tedte rm inal clamps.
R Non- insulated parts of thete rm inal clamps
must not come into con tact wi thother me tal
parts while the jump lead/charging cable is
connected tothe battery/jump-s tart connec‐
tion point.
R The jump lead/charging cable must not
come into contact wi thany parts which may
mo vewhen the engine is running.
R Alw ays make sure that nei ther you nor the
battery is elect rostatically charge d. R
Keep away from fire and naked flames.
R Do not lean overth e batter y.
Obser vethe additional following points when
ch arging the battery:
R Only use battery charge rs tested and
appr oved for Mercedes-Benz.
R Read the battery charge r's operating instruc‐
tions before charging the batter y.
Obser vethe additional following points during
st arting assis tance:
R Starting assis tance may be pe rformed using
only batteries with a nominal voltage of 12V.
R The vehicles must not touch.
R Petrol engine: only acceptstarting assis‐
ta nce if the engine and exhaust sy stem are
cold. 458
Breakdown assis tance

Display messages
Possible causes/consequences and M
MSolutions
Active Brake Assist Func-
tions currently limited See
Owner's Manual *
Ve hicles with the Driving Assistance Package: Active Brake Assi stwith cross-traf fic function, Evasi veSteering
Assist or PRE‑SAFE ®
PLUS are temp orarily una vailable or only partially available.
Ve hicles without the Driving Assistance pa ckage: Active Brake Assi stistemp orarily una vailable.
The ambient conditions are outside the sy stem limits (/ page195). #
Drive on.
As soon as the ambient conditions are within the sy stem limits, the sy stem will become available again. #
Ifth e display message does not disappear, stop theve hicle while paying attention toroad and traf fic conditions
and restart the engine.
6
Restraint sys. malfunction
Consult workshop *T
herestra int sy stem is faulty (/ page 33). &
WARNING Risk of inju ryor fata l injury due toa malfunction in there stra int sy stem
If th ere stra int sy stem is malfunctioning, restra int sy stem components may be triggered unintentionally or
might not be triggered at all in theeve nt of an accident. This may af fect the seat belt tensioner or airbag, for
ex ample. #
Have there stra int sy stem checked and repaired immediately at a qualified specialist workshop. De
tection of a restra int sy stem fault:
R The restra int sy stem warning lamp 6does not light up when the ignition is switched on.
R The restra int sy stem warning lamp 6lights up continuously or repeatedly during a journe y. #
Consult a qualified specialist workshop immediatel y.522
Display messages and warning/indicator lamps

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions #
Have there stra int sy stem checked and repaired immediately at a qualified specialist workshop. #
Drive on carefully. #
Obser vethe messages on the multifunction displa y. #
Consult a qualified specialist workshop immediatel y. Seat belt
Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions
7 Seat belt warning lamp
lights up The
red seat belt warning lamp will light up once the engine has star ted.
In addition, a warning tone may sound.
The seat belt warning lamp reminds the driver and front passenger tofast entheir seat belts. #
Fasten your seat belt (/ page37).
If yo u ha veplaced objects on the front passenger seat, the seat belt warning lamp may remain lit.
7 Seat belt warning lamp
fl ashes The
red seat belt warning lamp flashes and an intermit tent wa rning tone sounds.
The driver or front passenger has not fastened their seat belt while theve hicle is in motion. #
Fasten your seat belt(/ page37).
There are objects on the front passenger seat. #
Remo vethe objects from the front passenger seat. Display messages and
warning/indicator lamps 567

Driving sy
stems Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions
L Wa rning lamp for dis tance
wa rning function The
red dis tancewarning lamp lights up while theve hicle is in motion.
The dis tance totheve hicle in front is too small forth e speed selected.
If th ere is an additional warning tone, you are approaching an obs tacle at too high a speed. #
Be prepared tobrake immediatel y. #
Increase the dis tance.
Fu nction of Active Brake Assi st .Engine
Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions
; Engine diagnosis warning
lamp The
yellow engine diagno stics warning lamp is lit while the engine is running.
A malfunction has occu rred in the engine, theex haust sy stem or the fuel sy stem.
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 qualified specialist workshop.
Ve hicles with a diesel engine: the fuel tank may ha vebeen run dr y. 568
Display messages and warning/indicator lamps

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions #
Start the engine thre eto four times af terre fuelling.
If th eye llow engine diagnosis warning lamp goes out, emer gency operation mode is cancelled. The vehicle need not
be checked.
æ Fu elreser ve wa rning lamp The
yellow fuel reser ve wa rning lamp lights up while the engine is running.
The fuel supp lyhas dropped into there ser verange. #
Refuel.
#
Electrical fault warning
lamp The
red elect rical fault warning lamp is lit.
There is a fault in the electrics. #
Obser vethe messages on the multifunction displa y.
?
Coolant warning lamp The
red coolant warning lamp is lit while the engine is running.
Po ssible causes:
R The temp erature sensor is malfunctioning
R The coolant le vel is too low
R The air supply tothera diator is obstructed
R The radiator fan is faulty
If th ere is an additional warning tone, the coolant temp erature has exceeded 120 °C. Displ
aymessa ges and warning/indicator lamps 569

Ac
tivating/deactivating the synchro‐
nisation function (cont rol panel) .......... 147
Ac tivating/deactivating the synchro‐
nisation function (multimedia sys‐
te m) ..................................................... 14 8
Air di stribution settings .......................1 47
Air-reci rculation mode ........................ .148
Au tomatic control ................................ 147
Calling up the air conditioning menu ... 147
Defrosting the windscreen ...................1 45
Demisting wind ows............................. 14 8
Fr ont air vents ..................................... 15 3
No te .................................................... 14 5
Re ar air vents ...................................... 154
Re sidual heat ....................................... 14 8
Sets the air flow ................................... 14 5
Setting (multimedia sy stem) ................1 47
Setting the air distribution ...................1 45
Setting thete mp erature ......................1 45
St ationary heater/ ventilation .............. 14 8
Switching on/off ................................. 14 6
Switching there ar wind owheater
on/off .................................................1 45
THERMATIC control panel .................... 14 5
THERMOTRONIC contro l panel ............14 5Ve
ntilating theve hicle (con venience
opening) ................................................ 87
Cockpit ........................................................ .6
Overview .................................................6
Cof fee cup symbol
see ATTENTION ASSIST
Combination switch ................................12 9
Compass .................................................. .371
Compu ter
see On-board computer
Connection status
Displ aying ............................................ 408
Overview ............................................ .408
Connectivity Switching transmission of theve hicle
position on/off .................................... 320
Contacts ................................................... 383
Calling up ............................................ 384
Deleting ............................................... 386
Deleting favo urites .............................. 386
Downloading (from mobile phone) ...... 384
Importing ............................................ 385
Importing (o verview) .......................... .385 Information .......................................... 383
Making a call ....................................... 385
Na me form at ...................................... .384
Options ................................................ 385
Saving as a favo urite .......................... .386
Selecting options for suggestions ........ 386
St oring ................................................ 385
Con venience closing ................................. 87
Con venience opening ................................ 87
Coolant (engine) Check le vel .......................................... 435
No tes .................................................. 503
Cooling see Climate control
Co pyright .................................................... 31
Cornering light ........................................ .131
Cross Traf fic Alert .................................. .236
Crosswind Assist Function/no tes .................................... 194
Cruise control .......................................... 201
Ac tivating ............................................ 203
Buttons ................................................ 203
Calling up a speed ............................... 203 Index
581

Ac
tive Steering Assist cur rently
una vailable See Owner's Manual .........525
Ac tive Steering Assist inoperative .......524
Ad aptive Highbeam Assist cur rently
una vailable See Owner's Manual .........559
Ad aptive Highbeam Assist inopera‐
tive ...................................................... 559
Ad aptive Highbeam Assist Plus cur‐
re ntly una vailable See Owner's Man‐
ual ...................................................... .560
Ad aptive Highbeam Assist Plus inop‐
erative ................................................ .560
¯ AdBlue sy stem fault Engine
st art not possible ................................ 539
¯Ad Blue system fault Perf.
re duced in XXX miles See Owner's
Manual ................................................ 538
¯ AdBlue sy stem fault Perf.
re duced: XXX km/h Nostart in XXX
km ...................................................... .538 ¯
AdBlue sy stem fault See Own‐
er's Manual ........................................ .538
4Ad d 1 litre engine oil when next
re fuelling ............................................. 536
Anti-theft ala rmsystem Malfunction ... 556
Apply brake todeselect Park (P)
position ...............................................5 40
Apply brake toselect R ........................ 543
À ATTENTION ASSIST inoperative ... 526
ÀAT TENTION ASSIS T:Take a
break! .................................................. 525
bAu tomatic driving lights inoper‐
ative .................................................... 559
Au xilia rybattery malfunction ...............541
_ Before starting the engine, turn
th esteering wheel. .............................. 544
Blind Spot Assi stcur rently una vaila‐
ble See Owner's Manual ...................... 523
Blind Spot Assist inope rative ............... 524 Blind Spot Assi
stnot available when
to wing a trailer See Owner's Manual ...5 26
Brake immediate ly............................... 51 0
Á Changekey bat teries .................. 550
JCheck brake fluid le vel................ .515
Check brake pads See Owner's Man‐
ual ...................................................... .523
ïChe cktrailer hitch lo ck(white
display message) .................................5 52
Che cktyre pressu resth en restart
Ru n Flat Indicator ................................ 549
h Check tyre(s) .............................. .546
!Clean the fuel filter ...................... 531
Clutch overheated Avoid pulling away
fo r XX:XX mins .................................... .541
? Coolant Stop vehicle Switch
engine off ............................................ 534
Cruise contro l and Limiter inope ra‐
tive ...................................................... 529
Cruise control inope rative ................... 529 584
Index