check engine MERCEDES-BENZ A-CLASS SALOON 2018 User Guide

&
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

#
Vehicles with automatic transmission
must not be tow- star ted. #
Vehicles with automatic transmission must
not be tow- star ted.
Ve hicles with manual transmission #
Obser vethe no tes on towing away
( / page 461). #
If necessar y,allow the engine and exhaust
sy stem tocool down. #
Switch the ignition on. #
Enga gesecond gear. #
Release the electric parking brake. #
Tow- start theve hicle while the clutch pedal
is fully depressed. #
Slowly release the clutch pedal. #
Immediately shift toneutral if the engine
st arts. #
Pull over and stop theve hicle, paying atten‐
tion toroad and traf fic conditions. #
Remo vetheto w bar. #
Remo vetheto wing eye. #
Have theve hicle checked at a qualified spe‐
cialist workshop. Electrical fuses
Note
s on electrical fuses &
WARNING Risk of accident and inju ry
due to ov erloaded lines
If yo u manipulate or bridge a faulty fuse or if
yo ure place it with a fuse with a higher
amperage, the electric line could be overloa‐
ded.
This could result in a fire. #
Alw aysre place faulty fuses with speci‐
fi ed new fuses conta iningthe cor rect
amperage. *
NO
TEDama gedue toincor rect fuses Electrical components or sy
stems may be
damaged byincor rect fuses, or their func‐
tionality may be significant lyimpaired. #
Only use fuses that ha vebeen appr oved
by Mercedes-Benz and which ha vethe
cor rect fuse rating. Blown fuses mu
stbe replaced with fuses of the
same rating, which you can recognise bythe col‐
our and fuse rating. The fuse ratings and fu rther
information tobe obser ved are lis ted in the fuse
assignment diagram.
Fu se assignment diag ram: onthe fuse box in
th e engine compartment (/ page 466).
* NO
TEDama geor malfunctions caused
by moisture Moisture may cause dama
getothe electrical
sy stem or cause it tomalfunction. #
When the fuse box is open, make sure
th at no moisture can enter the fuse
box. #
When closing the fuse box, make sure
th at the seal of the lid is positioned cor‐
re ctly on the fuse box. Breakdown assis
tance 465

Ad
Blue ®
re sidues cr ystallise af ter a period of
time, and contamina tethe sur faces wi thwhich
th ey come into contact. Clean the dirty sur faces
wi th wate r as soon as possible.
When you open theAd Blue ®
tan k,small
amounts of ammonia vapour may escape. Do
not inhale any ammonia vapours that may be
re leased. Only fill th eAd Blue ®
tank in well-venti‐
lated areas.
Ad Blue ®
filling capacity and consum ption
To tal capacity of AdBlue ®
tank Mode
lT otal capacity
All models 23.8 lAd
Blue ®
consu mption
Like fuel consu mption, AdBlue ®
consu mption is
highly dependent upon driving style and operat‐
ing conditions. Forth is reason, your vehicle's
actual consum ption figures under normal operat‐
ing conditions may dif fer from the consum ption
fi gures calculated. AdBlue ®
consu mption is
between 1% and 5% of fuel consumption. Ha veth
eAd Blue ®
supply checked at a qualified spe‐
cialist workshop before making journe ysoutside
of Europe. Before a longer stay outside of
Europe, consult a qualified specialist workshop.
Display theAd Blue ®
ra nge and le vel
( / page 260). Engine oil
Note
s on engine oil
Obser vethe no tes on operating fluids
(/ page 496). *
NO
TEEngine dama gecaused byan
incor rect oil filter, incor rect oil or addi‐
tives #
Do not use engine oils or oil filters
which do not cor respond tothe specifi‐
cations explicitly prescribed forthe
service inter vals. #
Do not alter the engine oil or oil filter in
order toachie velonger change inter vals
th an presc ribed. #
Do not use additives. #
Have the engine oil rene we d at regular
inter vals. Mercedes-Benz
recommends that you ha vethe
oil change car ried out at a qualified specialist
wo rkshop.
Only Mercedes-Benz appr oved engine oils may
be used in Mercedes-Benz engines.
Fu rther information on engine oil and oil filters is
av ailable at thefo llowing locations:
R inthe Mercedes-Benz Specifications for
Operating Fluids byentering the designation Te
ch nical da ta501

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

Display messages
Possible causes/consequences and M
MSolutions #
Ifth e display message does not disappear, stop theve hicle while paying attention toroad and traf fic conditions
and restart the engine. Active Steering Assist cur-
rently unavailable See Own-
er's Manual
*A
ctive Steering Assist is temp orarily una vailable.
The ambient conditions are outside the sy stem limits (/ page211). #
Drive on.
As soon as the ambient conditions are within the sy stem limits, the sy stem will become available again. #
If necessar y,clean the windscreen in the camera's field of vision. #
Check the tyre pressure if necessar y.
À ATTENTION ASSIST: Take a
break! *A
TTENTION ASSIST has de tected fatigue or an increasing la ckof concentration on the part of the driver
(/ page 237). #
If necessar y,take a break.
Traffic Sign Assist inopera-
tive *T
raffic Sign Assist is malfunctioning. #
Consult a qualified specialist workshop.
Active Lane Keeping Assist
currently unavailable See
Owner's Manual *A
ctive Lane Keeping Assist is temp orarily una vailable.
The ambient conditions are outside the sy stem limits (/ page245). #
Drive on.
As soon as the ambient conditions are within the sy stem limits, the sy stem will become available again. Display messages and
warning/indicator lamps 525

Display messages
Possible causes/consequences and M
MSolutions #
Pull over and stop theve hicle safely as soon as possible, paying attention toroad and traf fic conditions. Do not
continue driving under any circums tances. #
Switch off the engine. #
Add 1 l engine oil. #
Check the engine oil le vel.
To p up engine oil (/ page 434).
No tes on engine oil (/ page 501).
4 Engine oil pressure Stop
Switch off engine *D
isplay message only for cer tain engines:
The engine oil pressure is too lo w.
* NO
TEEngine dama gecaused bydriving with insuf ficient engine oil pressure #
Avoid driving with insuf ficient engine oil pressure. #
Pull over and stop theve hicle safely as soon as possible, paying attention toroad and traf fic conditions. Do not
continue driving under any circums tances. #
Consult a qualified specialist workshop.
4 *D
isplay message only for cer tain engines:
The engine oil le vel has dropped tothe minimum le vel. 536
Display messages and warning/indicator lamps

Display messages
Possible causes/consequences and M
MSolutions &
WARNING Risk of an accident from driving wi thove rheated tyres
Overheated tyres may bur st, particularly at high speeds. #
Reduce speed so that the tyres cool down. #
Reduce speed so that the tyres cool down.
Check tyre pressures then
restart Run Flat Indicator *T
he tyre pressure loss warning sy stem generated a displ aymessa geand has not been restar ted since. #
When the tyre pressure is cor rect, restart the tyre pressure loss warning sy stem (/ page478).
Run Flat Indicator inopera-
tive *T
he tyre pressure loss warning sy stem is malfunctioning. #
Consult a qualified specialist workshop. Key
Display messages
Possible causes/consequences and M MSolutions
Á Key not detected (red dis‐
play message) *T
hekey cannot be de tected and may no longer be in theve hicle.
The key is no lon ger in theve hicle and you swit choff the engine:
R You can no lon gerst art the engine.
R You cannot centrally lock theve hicle. #
Ensure that theke y is in theve hicle. Display messages and
warning/indicator lamps 549

Display messages
Possible causes/consequences and M
MSolutions
ï Check trailer hitch lock
(white display message) *T
he trailer tow hit chis not operational when you are driving with a trailer. #
Stop theve hicle immediately, paying attention toroad and traf fic conditions, and switch off the engine. #
Uncouple the trailer and secure it against rolling away. #
Initiate a new swivelling procedure (/ page248). #
Ifth e ball neck is extended, press and hold the button on theta ilgate until the ball neck engages beneath the
bumper. #
When the display message disappears, couple up the trailer and drive on. &
WARNING Risk of an accident if the ball neck is not loc ked
If th e ball neck is not in the loc ked position, the trailer may come loose. #
Pull over and stop theve hicle safely as soon as possible, paying attention toroad and traf fic conditions.
Do not continue driving under any circums tances. #
Uncouple the trailer and secure it against rolling away. #
Initiate a new swivelling procedure and do not re-couple the trailer until the display message disappears. If
th e display message does not disappear, the trailer tow hit chis defective and the ball neck is not loc ked. #
Do not couple up the trailer. Drive on without the trailer. No tethere duced ground clearance due tothe
unlo cked ball nec k. #
Consult a qualified specialist workshop.
The trailer tow hit chis not operational when theve hicle is at a standstill. 552
Display messages and warning/indicator lamps

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions #
Pull over and stop theve hicle safely as soon as possible, paying attention toroad and traf fic conditions. Do not
continue driving under any circums tances. #
Obser vethe messages on the multifunction displa y. #
Consult a qualified specialist workshop.
! ABS warning lamp The
yellow ABS warning lamp is lit while the engine is running.
ABS is malfunctioning.
If th ere is an additional warning tone, EBD is malfunctioning.
Other driving sy stems and driving saf ety sy stems may also be malfunctioning. &
WARNING Thereisrisk of skidding if EBD or ABS is malfunctioning
If EBD or ABS is malfunctioning, the wheels could lock when braking
The steering capability and braking characteristics are thus se verely impaired. The braking dis tance may increase in
an emergency braking situation. In addition, other driving saf ety sy stems are switched off. #
Drive on carefull y. #
Have the brake sy stem checked immediately at a qualified specialist workshop. #
Drive on carefully. #
Obser vethe messages on the multifunction displa y. #
Consult a qualified specialist workshop. Display messages and
warning/indicator lamps 563

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions
! Re d indicator lamp, elect ric
parking brake applied
!
Ye llow elect ric pa rking
brake indicator lamp is mal‐
functioning The
red elect ric pa rking brake indicator lamp flashes or is lit. The yellow indicator lamp is also lit if the electric parking
brake malfunctions. #
Obser vethe messages on the multifunction displa y.
J
Brake sy stem warning lamp
(yellow) The
yellow brake sy stem warning lamp is lit while the engine is running. &
WARNING Risk of an accident due toa brake sy stem malfunction
If th e brake sy stem is malfunctioning, braking characteristics may be impaired. #
Drive on carefull y. #
Have the brake sy stem checked immediately at a qualified specialist workshop. #
Adjust your speed and continue todrive carefull y,leaving a suitable dis tance totheve hicle in front. #
Ifth e multifunction display sho wsa display message, please obse rveth is. 564
Display messages and warning/indicator lamps