check engine light MERCEDES-BENZ CLA-Class 2017 C117 User Guide

Limited braking performance on salt-
treated roads
If you drive on salted roads, a layer of salt resi-
due may form on the brake discs and brake
pads. This can result in a significantly longer
braking distance.
RIn order to prevent any salt build-up, apply the
brakes occasionally while paying attention to the traffic conditions.
RCarefully depress the brake pedal and the
beginning and end of a journey.
RMaintain a greater distance to the vehicle
ahead.
Servicing the brakes
!The brake fluid level may be too low, if:
Rif the red brake warning lamp lights up in
the instrument cluster and
Ryou hear a warning tone while the engine is
running
Observe additional warning messages in the
multifunction display.
The brake fluid level may be too low due to
brake pad wear or leaking brake lines.
Have the brake system checked immediately.
Consult a qualified specialist workshop to
arrange this.
!A function or performance test should only
be carried out on a 2-axle dynamometer. If
you wish to operate the vehicle on such a
dynamometer, please consult a qualified spe- cialist workshop in advance. You could oth-
erwise damage the drive train or the brake
system.
!As the ESP®system operates automatically,
the engine and the ignition must be switched
off (the SmartKey must be in position 0or 1in
the ignition lock) if:
Rthe electric parking brake is tested on a
brake dynamometer (for a maximum of
ten seconds)
Rthe vehicle is towed with the front axle
raised.
Braking triggered automatically by ESP
®may
seriously damage the brake system.
All checks and maintenance work on the brake
system must be carried out at a qualified spe-
cialist workshop. Have brake pads installed and brake fluid
replaced at a qualified specialist workshop.
If the brake system has only been subject to
moderate loads, you should test the functional-
ity
of your brakes at regular in

tervals.
You can find a description of Brake Assist (BAS)
on (
Ypage 60).
Mercedes-Benz recommends that you only have
brake pads/linings installed on your vehicle
which have been approved for Mercedes-Benz
vehicles or which correspond to an equivalent
quality standard. Brake pads/linings which have
not been approved for Mercedes-Benz vehicles
or which are not of an equivalent quality could
affect your vehicle's operating safety.
Mercedes-Benz recommends that you only use
brake fluid that has been specially approved for
your vehicle by Mercedes-Benz, or which corre-
sponds to an equivalent quality standard. Brake
fluid which has not been approved for
Mercedes-Benz vehicles or which is not of an
equivalent quality could affect your vehicle's
operating safety.
Checking brake lining thickness
You can measure the break pad/lining thick-
ness using a test gage. Color-coding (green or
red) on the test gage allows you to determine
whether the brake pad/lining thickness is still
sufficient. The test gage is in the vehicle docu-
ment wallet in the glove box.
Front wheel
146Driving tips
Driving and parking

Important safety notes
GWARNING
If you operate information systems and com-
munication equipmen tintegrate din th evehi-
cle while driving ,you will be distracte dfrom
traffic conditions. You could also lose control
of th evehicle. Ther eis aris kof an accident.
Only operate th eequipmen twhen th etraffic
situation permits. If you are no tsur ethat this
is possible ,park th evehicl epayin gattention
to traffic condition sand operate th eequip-
men twhen th evehicl eis stationary.
You must observ eth elegal requirements for th e
country in whic hyou are currentl ydriving when
operating th eon-board computer.
GWARNIN G
If th einstrumen tcluste rhas faile dor mal-
functioned, you may no trecognize function
restriction sin systems relevan tto safety. The
operating safet yof your vehicl emay be
impaired .Ther eis aris kof an accident.
Drive on carefully. Hav eth evehicl echecke d
at aqualified specialist workshop immedi-
ately.
The on-board computer only shows message sor
warning sfrom certain systems in th emultifunc-
tion display. You should therefor emak esur e
your vehicl eis operating safely at all times .
If th eoperating safet yof your vehicl eis
impaired ,pull ove ras soo nas it is saf eto do so.
Contac t aqualified specialist workshop.
Fo ran overview, see th einstrumen tpanel illus-
tration (
Ypage 32).
Displays and operation
Instrument cluster lighting
The ligh tsensor in th einstrumen tcluste rauto -
matically control sth ebrightness of th emulti-
function display. In daylight, th edisplays in th e
instrumen tcluste rare no tilluminated.
The lighting in th einstrumen tcluster, in th edis-
plays and th econtrol sin th evehicl einterior can
be adjusted usin gth ebrightness control knob. The brightness control knob is locate
don th e
botto mleftof th einstrumen tcluste r
(
Ypage 32).
XTurn th ebrightness control knob clockwise or
counter-clockwise.
If th eligh tswitch is set to th eÃ, Tor
L position ,th ebrightness is dependen t
upon th ebrightness of th eambien tlight.
Speedometer with segments
The speedometer is divided int osegments on
vehicles wit hDistanc ePilot DISTRONIC.
The segments in th espeedometer indicat e
whic hspee drange is available.
RDistanc ePilot DISTRONI Cis activated
(Ypage 150):
On eor two segments in th eset spee drange
ligh tup.
RDistanc ePilot DISTRONI Cdetects avehicl ein
fron tmoving mor eslowly than th estore d
speed:
The segments between th espee dof th evehi-
cle in fron tand th estore dspee dligh tup.
Tachometer
!
Do no tdriv ein th eoverrevving range, as this
could damag eth eengine.
The red ban din th etachometer indicates th e
engine's overrevving range.
The engin eis limite dwithin arange to protect
th eengin ewhen th ered ban dis reached.
Outside temperature display
You should pay special attention to road condi-
tion swhen temperatures are aroun dfreezing
point.
Bea rin min dthat th eoutside temperature dis-
play indicates th etemperature measured and
does no trecord th eroad temperature.
The outside temperature display is in th emulti-
function display (
Ypage 176).
Ther eis ashort delay before achang ein outside
temperature appear sin th emultifunction dis-
play.
174Displays and operation
On-board computer and displays

Display messagesPossible causes/consequences andMSolutions
The yellow!warning lamp lights up and th ered F (USAonly)
or ! (Canada only) indicator lamp flashes .
It is no tpossibl eto apply th eelectric parking brak emanually.
XShift th etransmission to position P.
XVisitaqualified specialist workshop .
$(USA
only)
J( Canada
only)
Check Brake Fluid
Level
There is no tenough brak efluid in th ebrak efluid reservoir .
A warning tone sounds. The $(USAonly) or J(Canada only)
warning lamp sin th einstrumen tcluste rmay also ligh tup.
GWARNIN G
The braking effec tmay be impaired.
There is aris kof an accident.
XPull ove rand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions. Do no tcontinu edrivin g
under any circumstances.
XSecur eth evehicl eagainst rollin gaway (Ypage 140).
XConsult aqualified specialist workshop .
XDo notadd brak efluid .This does no tcorrec tth emalfunction .
#
CheckBrakePadWear
The brak epads/linings hav ereached their wear limit.
XVisit aqualified specialist workshop .
G
Inoperative
Oneor mor emain features of th embrace system are malfunctioning .
XVisitaqualified specialist workshop .
ActiveBrakeAssistFunctionsCurrentlyLimitedSee Opera‐tor's Manual
Active Brake Assis tis temporarily inoperative.
Possibl ecauses are:
Rth eradar sensor system is temporarily inoperative, e.g. due to elec -
tromagneti cradiation emitted by nearby TV or radi ostation sor
other source sof electromagneti cradiation
Rth esystem is outside th eoperating temperature range
Rth eon-boar dvoltag eis to olow
Whe nth ecauses state dabov eno longer apply, th edisplay message
disappears.
Active Brake Assis tis operational again .
If th edisplay message does no tdisappear :
XPull overand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 140).
XRestart th eengine.
Active BrakeAssist :SystemInop‐erative
Active Brake Assis tis unavailable due to amalfunction .Situation -
dependen tparking assistanc emay also hav efailed.
XVisit aqualified specialist workshop immediately.
194Display messages
On-board computer and displays

Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
!FNF (USA only), !(Canada only): the red indicator lamp for the electric
parking brake flashes or lights up and/or the yellow warning lamp for the electric
parking brake lights up.
XObserve the additional display messages in the multifunction display.
6N The red restraint system warning lamp is lit while the engine is running.
The restraint system is malfunctioning.
GWARNING
The air bags or Emergency Tensioning Devices may either be triggered uninten-
tionally or, in the event of an accident, may not be triggered.
There is an increased risk of injury.
XObserve the additional display messages in the multifunction display.
XDrive on carefully.
XContact a qualified specialist workshop and have the restraint system checked.
For further information about the restraint system, see (
Ypage 39).
Engine
Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
;NThe yellow Check Engine warning lamp lights up while the engine is running.
There may be a malfunction, for example:
Rin the engine management
Rin the fuel injection system
Rin the exhaust system
Rin the ignition system
Rin the fuel system
The emission limit values may be exceeded and the engine may be in emergency
mode.
XVisit a qualified specialist workshop immediately.
iIn some states, you must immediately visit a qualified specialist workshop as
soon as the yellow Check Engine warning lamp lights up. This is due to the legal
requirements in effect in these states. If in doubt, check whether such legal
regulations apply in the state in which you are currently driving.
æN The yellow reserve fuel warning lamp lights up while the engine is running.
The fuel level has dropped into the reserve range.
XRefuel at the nearest gas station.
222Warning and indicator lamps in the instrument cluster
On-board computer and displays

Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
æNThe yellow reserve fuel warning lamp flashes while the vehicle is in motion.
In addition, the ;Check Engine warning lamp may light up.
The fuel filler cap is not closed correctly or the fuel system is leaking.
XCheck that the fuel filler cap is correctly closed.
XIf the fuel filler cap is not correctly closed: close the fuel filler cap.
XIf the fuel filler cap is closed:visit a qualified specialist workshop.
?NThe red coolant warning lamp lights up while the engine is running and the
coolant temperature gage is at the start of the scale.
The temperature sensor for the coolant temperature gauge is malfunctioning.
The coolant temperature is no longer being monitored. There is a risk of engine
damage if the coolant temperature is too high.
XPull over and stop the vehicle safely and switch off the engine, paying attention
to road and traffic conditions. Do not continue driving under any circumstances.
XSecure the vehicle against rolling away (Ypage 140).
XConsult a qualified specialist workshop.
Warning and indicator lamps in the instrument cluster223
On-board computer and displays
Z

XMake sure that the windshield wipers are
switched off.
XPull release lever:on the hood.
The hood is released.
XReach into the gap between the hood and the radiator trim and press hood catch lever ;to
the left.
XRaise the hood.
XPull support strut ?out of bracket A.
XLift up support strut ?and insert it into yel-
low retaining clip =.
Closing the hood
XRaise the hood slightly and, at the same time,
remove support strut ?from yellow retaining
clip =.
XSwing support strut ?down and press it into
bracket Auntil it engages.
XLower the hood and let it fall from a height of
approximately 8 in (20 cm).
XCheck that the hood has engaged properly.
If the hood can be raised slightly, it is not
properly engaged. Do not press the hood
closed. Open the hood again and close it with
a little more force.
Engine oil
General notes
Depending on your driving style, the vehicle
consumes up to 0.9 US qt (0.8 liters) of oil per
600 miles (1,000 km). The oil consumption may
be higher than this when the vehicle is new or if
you frequently drive at high engine speeds.
Depending on the engine, the oil dipstick may be
in a different location.
When checking the oil level:
Rpark the vehicle on a level surface.
Rthe engine should be switched off for approx-
imately five minutes if the engine is at normal
operating temperature.
Rif the engine is not at normal operating tem-
perature, e.g. if the engine was only started
briefly, wait about 30 minutes before carrying
out the measurement.
Checking the oil level using the oil dip-
stick
GWARNING
Certain components in the engine compart-
ment, such as the engine, radiator and parts
of the exhaust system, can become very hot.
Working in the engine compartment poses a
risk of injury.
Where possible, let the engine cool down and touch only the components described in the
following.
Engine compartment255
Maintenance and care
Z

GWARNING
During charging and jump-starting, explosive gases can escape from the battery. There is a risk of an explosion.
Particularly avoid fire, open flames, creating sparks and smoking. Ensure there is sufficient ven-
tilation while charging and jump-starting. Do not lean over a battery.
GWARNING
During the charging process, a battery produces hydrogen gas. If a short circuit occurs or sparks
are created, the hydrogen gas can ignite. There is a risk of an explosion.
RMake sure that the positive terminal of a connected battery does not come into contact with
vehicle parts.
RNever place metal objects or tools on a battery.
RIt is important that you observe the described order of the battery terminals when connecting
and disconnecting a battery.
RWhen jump-starting, make sure that the battery poles with identical polarity are connected.
RIt is particularly important to observe the described order when connecting and disconnecting
the jumper cables.
RNever connect or disconnect the battery terminals while the engine is running.
GWARNING
A discharged battery can freeze at temperatures below freezing point. When jump-starting the
vehicle or charging the battery, gases can escape from the battery. There is a risk of an explosion. Allow the frozen battery to thaw out before charging it or jump-starting.
!Avoid repeated and lengthy starting attempts. Otherwise, the catalytic converter could be
damaged by the non-combusted fuel.
If the indicator/warning lamps do not light up in the instrument cluster at low temperatures, it is very
likely that the discharged battery has frozen. In this case you may neither jump-start the vehicle nor
charge the battery. Let the battery thaw first. The service life of a thawed-out battery may be shorter.
The starting characteristics can be impaired, particularly at low temperatures. Have the thawed-out
battery checked at a qualified specialist workshop.
Do not start the vehicle using a rapid charging device. If your vehicle's battery is discharged, the
engine can be jump-started from another vehicle or from a second battery using jumper cables.
Observe the following points:
RThe battery is not accessible in all vehicles. If the other vehicle's battery is not accessible, jump-
start the vehicle using a second battery or a jump-starting device.
RYou may only jump-start the vehicle when the engine and exhaust system are cold.
RDo not start the engine if the battery is frozen. Let the battery thaw first.
ROnly jump-start from batteries with a 12 V voltage rating.
ROnly use jumper cables that are not damaged and have a sufficient cross-section and insulated terminal clamps.
RMake sure that the two vehicles do not touch.
274Jump-starting
Breakdown assistance

Make sure that:
RThe jumper cables are not damaged.
RNon-insulated parts of the terminal clamps do not come into contact with other metal parts while
the jumper cables are connected to the battery
RThe jumper cables cannot come into contact with parts that can move when the engine is running,
such as the V-belt pulley or the fan
XSecure the vehicle by applying the electric parking brake.
XShift the transmission to positionP.
XTurn the SmartKey to position0in the ignition lock and remove it.
XSwitch off all electrical consumers, e.g. rear window defroster, lighting, etc.
XOpen the hood.
Position numberBidentifies the charged battery of the other vehicle or an equivalent jump-starting
device.
XPress together cover :of positive clamp ;and slide it back.
XConnect positive terminal ;on your vehicle to positive terminal =of donor battery Busing the
jumper cable, beginning with your own battery.
XStart the engine of the donor vehicle and run it at idling speed.
XConnect negative terminal ?of donor battery Bto ground point Aof your vehicle using the
jumper cable, connecting the jumper cable to battery of other vehicle Bfirst.
XIf the battery is fully discharged, leave the battery that is being used to jump-start connected for
a few minutes before attempting to start. This charges the battery slightly.
XStart the engine.
XBefore disconnecting the jumper cables, let the engine run for several minutes.
XFirst, remove the jumper cables from ground point Aand negative terminal ?, then from pos-
itive clamp ;and positive terminal =. Begin each time at the contacts on your own vehicle first.
XClose cover:of positive terminal ;after removing the jumper cables.
XClose the hood.
XHave the battery checked at a qualified specialist workshop.
iJump-starting is not considered to be a normal operating condition.
Jump-starting275
Breakdown assistance
Z