check engine MERCEDES-BENZ CLA COUPE 2018 User Guide

ProblemPossible causes/consequences andMSolutions
KEYLESS-GO is malfunctioning.
XLock/unlock the vehicle using the remote control function of the
SmartKey.
XHave the vehicle and SmartKey checked at aqualified specialist
workshop.
If the vehicle can also not be locked/unlocked using the remote con-
trol function:
XUnlock (Ypage 77) or lock (Ypage 77) the vehicle using the
mechanical key.
XHave the vehicle and SmartKey checked at aqualified specialist
workshop.
The engine cannot be
started using the Smart-
Key.The on-board voltage is too low.
XSwitch off non-essential consumers, e.g. seat heating or interior
lighting, and try to start the engine again.
If this does not work:
XCheck the starter battery and charge it if necessary (Ypage 278).
or
XJump-start the vehicle (Ypage 278).
or
XConsult aqualified specialist workshop.
The engine cannot be
started using the Start/
Stop button. The Smart-
Key is in the vehicle.The vehicle is locked.
XUnlock the vehicle and try to start the vehicle again.
The SmartKey battery is discharged or nearly discharged.
XCheck the SmartKey battery (Ypage 73) and replace it if necessary
(Ypage 73).
If this does not work:
XStart your vehicle with the SmartKey in the ignition lock.
There is interference from apowerful source of radio waves.
XStart your vehicle with the SmartKey in the ignition lock.
You have lost aSmart-
Key.XHave the SmartKey deactivated at aqualified specialist workshop.
XReport the loss immediately to the vehicle insurers.
XIf necessary, have the locks changed as well.
You have lost the
mechanical key.XReport the loss immediately to the vehicle insurers.
XIf necessary, have the locks changed as well.
SmartKey75
Opening and closing
Z

XPress the lockingbutton on the driver’s door
(Ypage 76).
XCheck whether the lockin gknobs on the
front-passenger door and the rear doors are
still visible. Press down the lockin gknobs by
hand, if necessary.
XClose the driver's door.
XTake the mechanical key out of the SmartKey
(Ypage 72).
XInsert the mechanical key into the lock of the
driver's door as far as it will go.
XTurn the mechanical key clockwise as far as it
will go to position 1.
XTurn the mechanical key back and remove it.
XMake sure that the doors and the trunk lid are
locked.
XInsert mechanical key into the SmartKey
(Ypage 72).
iIf you lock the vehicle as described above,
the fuel filler flap is not locked. The anti-theft
alarm system is not armed.
Trunk
Important safety notes
GWARNING
Combustion engines emit poisonous exhaust
gases such as carbon monoxide. Exhaust
gases can enter the vehicle interior if the
trunk lid is open when the engine is running,
especially if the vehicle is in motion .There is a
risk of poisoning.
Always switch off the engine before opening
the trunk lid. Never drive with the trunk lid
open.
GWARNING
If objects, luggage or loads are not secured or
not secured sufficiently, they could slip, tip
over or be flung around and thereby hit vehicle
occupants. There is arisk of injury, particu-
larly in the event of sudden braking or asud-
den change in direction.
Always store object ssothat they cannot be
flung around. Secure objects, luggage or
loads against slipping or tipping before the
journey.
!The trunk lid swings upwards when opened.
Therefore, make sure that there is sufficient
clearance above the trunk lid.
The opening dimensions of the trunk lid can be
found in the "Vehicle data" section
(
Ypage 320).
You should preferably place luggage or loads in
the trunk .Observe the loading guidelines
(
Ypage 237).
Do not leave the SmartKey in the trunk .You
could otherwise lock yourself out.
The trunk lid can be:
Ropened and closed manually from outside
Ropened automatically from outside
Ropened automatically from inside
Rreleased with the emergencyr elease from the
inside
Opening/closing from outside
Opening
XPress the %button on the SmartKey.
XPull handle :.
XRaise the trunk lid.
78Trunk
Opening and closing

Problems with the seat heating
ProblemPossible causes/consequences andMSolutions
The seat heating has
switched off prematurely
or cannot be switched
on.The on-board voltage is too low because too many electrical consum-
ers are switched on.
XSwitch off electrical consumers that you do not need, such as the
rear window defroster or interior lighting.
Once the battery is sufficiently charged, the seat heating will switch
back on automatically.
Steering wheel
Important safety notes
GWARNING
You could lose control of your vehicle if you do the following while driving:
Radjust the driver's seat, head restraint,
steering wheel or mirrors
Rfasten the seat belt
There is arisk of an accident.
Adjust the driver's seat, head restraint,s teer-
ing wheel and mirror and fasten your seat belt before startin gthe engine.
GWARNING
Children could injure themselves if they
adjust the steering wheel. There is arisk of
injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children unsupervised in the vehicle.
Adjusting the steering wheel
GWARNING
If the steering wheel is unlocked while the
vehicle is in motion, it could change position
unexpectedly. This could cause you to lose
control of the vehicle. There is arisk of an
accident.
Before startin goff, make sure the steering
wheel is locked. Never unlock the steering
wheel while the vehicle is in motion.
:Release lever
;Adjustst he steering wheel height
=Adjuststhe steering wheel position (fore-
and-aft adjustment)
XPush release lever :down completely.
The steering column is unlocked.
XAdjust the steering wheel to the desired posi-
tion.
XPush release lever :up completely.
The steering column is locked.
XCheck if the steering column is locked. When
doing so, try to push the steering wheel up or down or try to move it in the fore-and-aft
direction.
Steering wheel95
Seats, steering wheela nd mirrors
Z

GWARNING
Flammable materials introduced through
environmental influence or by animals can
ignite if in contact with the exhaust system or
parts of the engine that heatu p. There isarisk
of fire.
Carry out regular checks to make sure that
there are no flammable foreignm aterials in
the engine compartment or in the exhaust
system.
General notes
During acold start, the engine runs at higher
speeds to enabl ethe catalytic converter to
reach its operating temperature. The sound of
the engine may change during this time.
Automatic transmission
XShift the transmission to position j
(Ypage1 30).
The transmission position display in the mul-
tifunction display shows P(
Ypage1 30).
iYou can start the engine in transmission
position jand i.
Starting procedure with the SmartKey
To start the engine using the SmartKey instead
of the Start/Stop button, pul lthe Start/Stop
button out of the ignitio nlock.
XTurn the SmartKey to position 3in the igni-
tion lock (Ypage1 22) and release it as soon
as the engine is running.
Starting procedure with the Start/Stop
button
The Start/Stop button can be used to start the
vehiclem anually without inserting the SmartKey
into the ignitio nlock. The Start/Stop button
must be inserted in the ignitio nlock and the
SmartKey must be in the vehicle. This mode for
starting the engine operates independently of
the ECO start/stop automatic engine start func-
tion.
You can start the engine if avalidS martKey is in
the vehicle. Switch off the engine and always
take the SmartKey with you when leaving the vehicle, even if you only leave it for
ashort time.
Pay attention to the important safety notes.
XDepress the brake pedala nd keep it
depressed.
XPress the Start/Stop button once
(Ypag e122).
The engine starts.
Starting procedure via smartphone
Observe the important safety notes on starting
the engine (Ypag e123).
You can als ostart you rengine via you rsmart-
phone from outside the vehicle. In this case, the
previousl yselected climate control setting is
activated. In this way you can cool or heat the
interior of the vehicleb efore starting the jour-
ney.
Only start the engine via you rsmartphone if it is
safe to start and run the engine where you rvehi-
cle is parked.
Observe the legals tipulations in the area where
you rvehicleisp arked.Engine start via smart-
phone may be limited to certain countries or
regions.
You can execute amaximu moftwo consecutive
starting attempts via you rsmartphone. If you
insert the SmartKey into the ignitio nlock, you
can carry out two more starting attempts.
Once you have started the engine, you can
switch the engine off via you rsmartphone at any
time.
You can only start the engine via you rsmart-
phone if:
Rthe SmartKey is in the ignitio nlock
Rpark position jis selected
Rthe accelerator pedalisn ot depressed
Rthe anti-theft alarm system is not activated
Rthe panicalarm is not activated
Rthe hazard warning lamp sare switched off
Rthe hood is closed
Rthe doors are closed and locked
Rthe windows and sliding sunroof are closed
Also make sure that:
Rthe fuel tank is sufficiently filled
Rthe starter battery is sufficiently charged
GWARNING
Limbs coul dbecrushedortrappe difthe
engine is started unintentionally during ser-
124Driving
Driving and parking

ProblemPossible causes/consequences andMSolutions
The engine does not
start. You cannot hear
the starter motor.The on-board voltage is too low because the battery is too weak or
discharged.
XJump-start the vehicle (Ypage 278).
If the engine does not start despite attempt stojump-start it:
XConsult aqualified specialist workshop.
The starter motor was exposed to athermal load that was too high.
XAllow the starter motor to cool down for approximately two minutes.
XTry to start the engine again.
If the engine still does not start:
XConsult aqualified specialist workshop.
The engine is not running
smoothly and is misfir-
ing.There is amalfunction in the engine electronics or in amechanical
componentoft he engine management system.
XOnly depress the accelerator pedal slightly.
Otherwise, non-combusted fuel may get into the catalytic converter
and damage it.
XHave the cause rectified immediately at aqualified specialist work-
shop.
The coolant temperature
gauge shows avalue
above 248 ‡(120 †).
The coolant warning
lamp may also be on and
aw arning tone may
sound.The coolant level is too low. The coolant is too hot and the engine is no
longer being cooled sufficiently.
XStop as soon as possible and allow the engine and the coolant to
cool down.
XCheck the coolant level (Ypage 260). Observe the warning notes
as you do so and add coolant if necessary.
DYNAMIC SELECTb utton (all vehicles
except Mercedes-AMG vehicles)
Use the DYNAMIC SELECT button to change the
drive program. Depending on the drive program
selected the following vehicle characteristics
will change:
Rthe drive (engine and transmission manage-
ment)
Rthe suspension (vehicles with damping sys-
tem or AMG adaptive sport suspension sys-
tem)
Rthe steering
Rthe availability of the ECO start/stop function
Rthe climate control:
Each time you start the engine with the Smart-
Key or the Start/Stop button, drive program Cis
activated. For further information about starting
the engine, see (
Ypage 125).
XPress DYNAMIC SELECT button :as many
times as necessary until the desired drive
program is selected.
The selected drive program appears in the
multifunction display.A fter five seconds the
display goes out and the status icon of the
selected drive program appears.
128DYNAMIC SELECT button (all vehicles except Mercedes-AMG vehicles)
Driving and parking

Transmission positions
BPark position
Thisprevents the vehicl efromr olling
away when stopped.
Onlys hift the transmission to posi-
tion jwhen the vehicl eisstation-
ary. The parkin gloc ks houl dnot be
used as abrake when parking.
Alway sapply the electronic parking
brake in additio ntothe parkin gloc k
in order to secur ethe vehicle.
In the event of amalfunctio nofthe
vehicle's electronics ,the transmis-
sion mayl ockinp osition j.H ave
the vehicl eelectronics checked
immediatel yataqualified specialist
workshop.
Park position jis automatically
engaged if:
Ryo us witch off the engine using the
SmartKeya nd remove the Smart-
Key
Ryo us witch off the engine using the
SmartKeyoru sing the Start/Stop
button and open the driver's door
or front-passenge rdoor
Ryouo pent he driver's door when
the vehicl eisstationar yorwhen
drivin gatav eryl ow spee dand the
transmission is in position hor
k
CRevers egear
Onlys hift the transmission into posi-
tion kwhen the vehicl eisstation-
ary.
ANeutral
Do not shift the transmission to i
whil edriving. The automatic trans-
mission could otherwis ebedam-
aged.
No powe ristransmitted fromt he
engine to the drive wheels.
Releasing the brakes will allo wyouto
mov ethe vehicl efreely, e.g .topush
it or tow it.
If ESP
®is deactivated or faulty: shift
the transmission to position iif the
vehicl eisind angerofs kidding,e.g.
on icy roads.
If yo uswitch the engine off with the
transmission in position korh,
the automatic transmission shifts to
i automatically.
!Coasting in neutral imay
cause damage to the drive train.
7Drive
The automatic transmission changes
gear automatically. All forward gears
ar ea vailable.
Driving tips
Changin ggear
The automatic transmission shifts throug hthe
individual gear sautomaticall ywhenitisint rans-
mission position h.Thisa utomatic gear shift-
ing behavio risdetermine dby:
Rthe selecte ddrive program
Rthe positio nofthe accelerator pedal
Rthe roa dspeed
Accelerator peda lposition
Your style of drivin ginfluences how the auto-
matic transmission shifts gear:
Rlittle throttle :early upshifts
Rmor ethrottle :lat eu pshifts
Automati ctransmission133
Driving an dparking
Z

Beforethe engine speed reaches the red area,
an upshift indicator will be shownint he multi-
function display.
XShift to recommende dgear :whe nmes-
sage ;is shownint he multifunction display.
Kickdown
XFor maximum acceleration, depress the
accelerator pedal beyond the pressure point.
The automatic transmission shifts to alower
geard epending on the engine speed.
XShift back up once the desire dspeed is
reached. During kickdown, yo
ucannot shift gears using
the steering wheel paddl eshifters.
If yo uapply fullthrottle ,the automatic trans-
missio nshifts up to the next gearw hent he
maximum engine speed is reached.T hispre-
vents the engine from overrevving.
Mercedes-AMG vehicles: it is only possible to
use kickdown in temporary manual drive pro-
gram M.Whenm anual drive program Mis per-
manently activated, kickdown is not possible.
Problems with the transmission
ProblemPossible causes/consequence sand MSolutions
The transmission has
problem sshifting gear.The transmission is losing oil.
XHave the transmission checkedataq ualified specialist workshop
immediately.
The acceleration ability
is deteriorating.
The transmission no lon-
ger shifts into al lofthe
gears.
Reverseg earcan no lon-
ger be engaged.The transmission is in emergency mode.
XStop the vehicle.
XShift the transmission to position j.
XSwitch off the engine.
XWait at least ten seconds before restarting the engine.
XShift the transmission to positionh.
XHave the transmission checkedataq ualified specialist workshop
immediately.
Refueling
Important safety notes
GWARNING
Fue lish ighly flammable. If yo uhandle fuel
incorrectly ,there is ariskoff ire and explo-
sion.
You mus tavoid fire ,openf lames, creating
sparks and smoking. Switch off the engine
and ,ifa pplicable, the auxiliary heating before
refueling.
GWARNING
Fue lisp oisonousa nd hazardoustoh ealth.
There is arisk of injury.
138Refueling
Drivin gand parking

XTurn the fuel filler cap counterclockwise and
remove it.
XInsert the fuel filler cap into the holder on theinside of fuel filler flap =.
XCompletely insert the filler neck of the fuel
pump nozzle into the tank ,hook in place and
refuel.
XOnly fill the tank until the pump nozzle
switches off.
Do not add any more fuel after the pump stops
filling for the first time. Otherwise, fuel may leak
out.
Closing the fuel filler flap
XReplace the cap on the filler neck and turn
clockwise until it engages audibly.
XClose the fuel filler flap. Close the fuel filler flap before lockingt
he vehi-
cle.
If you are driving with the fuel filler cap open, the
8 reserve fuel warning lamp flashes. Ames-
sage appears in the multifunction display
(
Ypage 206).
In addition, the ;Check Engine warning
lamp may light up (
Ypage 224).
For further information on warning and indicator
lamps in the instrument cluster, see
(
Ypage 224).
Problems with fuel and the fuel tank
ProblemPossible causes/consequences and MSolutions
Fuel is leaking from the
vehicle.The fuel line or the fuel tank is faulty.
GWARNING
Risk of explosion or fire.
XApply the electric parking brake.
XSwitch off the engine.
XRemove the SmartKey from the ignition lock.
or, in vehicles with KEYLESS-GO start-function or KEYLESS ‑GO
XOpen the driver's door.
The vehicle electronics are now in positiong.This is the same as
the SmartKey being removed from the ignition.
XDo not restart the engine under any circumstances.
XConsult aqualified specialist workshop.
The fuel filler flap cannot
be opened.The fuel filler flap is not unlocked.
XUnlock the vehicle (Ypage 70).
The SmartKey battery is discharged or nearly discharged.
XUnlock the vehicle using the mechanical key (Ypage 77).
The fuel filler flap is unlocked, but the opening mechanism is jammed.
XConsult aqualified specialist workshop.
140Refueling
Driving and parking

Limited braking performance on salt-
treated roads
If you driveonsalted roads,alayer of salt resi-
due may for monthebraked iscsand brake
pads. This can result in asignificantly longer
braking distance.
RIn ordertop revent any salt build-up, apply the
brakes occasionally while paying attention to th et raffic conditions.
RCarefully depress th ebrakep edal and the
beginnin gand end of ajou rney.
RMaintain agreater distanc etothevehicle
ahead.
Servicing th ebrakes
!The brakef luid level may be to olow, if:
Rif th ered brakew arning lamp lightsupi n
th ei nstrumentc luster and
Ryou hearawarning tone while th eengine is
running
Observe additional warning messages in the
multifunction display.
The brakef luid level may be to olow due to
brak epad wear or leaking brak elines.
Hav ethe brakes ystem checked immediately.
Consult aqualifie dspecialist workshop to
arrange this.
!Af unction or performanc etests hould only
be carried out on a2-axle dynamometer. If
you wish to operate th evehicle on such a
dynamometer, please consult aqualifie dspe-
cialis tworkshop in advance. You could oth-
erwis edamage th edrivet rain or th ebrake
system.
!As th eESP®system operates automatically,
th ee ngine and th eignitio nmust be switched
off (th eSmartKey must be in position uor
1 in th eignitio nlock), if th eelectric parking
brakeist ested onabraking dynamometer
(maximum 10 seconds).
Brakin gtriggered automatically by ESP
®may
cause severe damage to th ebrakes ystem.
All check sand maintenanc ework on th ebrake
system must be carried out at aqualifie dspe-
cialis tworkshop.
Hav ebrakep ads installe dand brakef luid
replaced at aqualifie dspecialist workshop. If th
ebrakes ystem has onl ybeen subject to
moderatel oads, you should tes tthe functional-
ity of your brakes at regular intervals.
You can fin dadescription of Brake Assist (BAS
)
on (Ypage 61).
Mercedes-Ben zrecommend stha tyou onl yhave
brak epads/linings installe donyour vehicle
whichh ave been approved for Mercedes-Benz
vehicle sorwhichcorrespondtoane quivalent
qualitys tandard. Brake pads/linings whichh ave
not been approved for Mercedes-Ben zvehicles
or whicha re not of an equivalent qualityc ould
affect your vehicle's operatin gsafety.
Mercedes-Ben zrecommend sthaty ou onl yuse
brakef luid that has been specially approved for
your vehicle by Mercedes-Benz, or whichc orre-
sponds to an equivalent qualitys tandard. Brake
fluid whichh as not been approved for
Mercedes-Ben zvehicle sorw hichisn ot of an
equivalent qualityc ould affect your vehicle's
operatin gsafety.
Checkingb rake lining thickness
You can measure th ebreak pad/linin gthick-
nes susingat estg age. Color-coding( green or
red) on th etestg age allows you to determine
whether th ebrakep ad/linin gthicknes sisstill
sufficient .The tes tgage is in th evehicle docu-
mentw allet in th egloveb ox.
Front wheel
Driving tips147
Driving and parking
Z

Rear wheel
XBring thevehicl eand wheels int oasuitable
position so that you can attach test gage A.
XSecurethe vehicl eagainst rollin gaway
(Ypage 141).
XEngage park position P.
XSwitchoff th eengine.
XPlac etestg age Abetween th ewheel's
spoke sonb rakepad/lining =.
XHold test gage Averticall yonb rak edisc :
and slid emeasurin gpin; onto brak e
disc :.
XChec kwhichc olor field ?thea rrow on
measurin gpin; is pointing to .
Green: theb rak epad/lining thickness is suf -
ficient.
Red :th eb rak epad/lining thickness is no t
sufficient. Hav ethe brak epads/lining
checke dataq ualified specialist workshop.
To avoi daninaccurat emeasurement:
Rmak esurey ou position th ewheels suitably
Rdo no tput th emeasurin gpin on arecess in
th eb rak edisc
Driving on wet roads
Hydroplaning
If water has accumulated to acertai ndept hon
th er oad surface, there is adanger of hydro-
planing occurring, eve nif:
Ryou driv eatlow speeds
Rthet ires hav eadequat etread dept h
Fo rthisr eason ,intheevent of heav yrain or in
condition sinwhichh ydroplaning may occur ,
you mus tdriveint hefollowin gmanner:
Rlower your spee d
Ravoidruts
Ravoi dsudde nsteering movement s
Rbrakecarefully
Driving on flooded roads
!Do no tdrivet hroug hflooded areas .Chec k
th ed ept hofa ny water before driving throug h
it .D rive slowly throug hstanding water. Oth-
erwise, water may ente rthe vehicl einterior or
th ee nginec om partment. This can damag e
th ee lectronic component sintheengin eor
th ea utomatic transmission .Water can also
be drawn in by th eengine's air suction nozzles
and this can caus eengined amage.
Winter driving
GWARNIN G
If you shif tdown on aslipper yroad surfac ein
an attemp ttoincreas ethe engine's braking
effect, th edrivew heels could lose their grip.
There is an increased danger of skiddin gand
accidents .
Do no tshif td own for additional engin ebrak -
ing on aslipper yroad surface.
GDANGER
If th eexhaust pipe is blocke doradequat e
ventilation is no tpossible, poisonous gase s
suc hasc arbon monoxide (CO) may ente rthe
vehicle. This is th ecase, e.g. if th evehicl e
become strapped in snow. There is arisko f
fatal injury.
148Driving tips
Driving and parking