lights MERCEDES-BENZ C-CLASS COUPE 2018 Repair Manual

Display messagesPossible causes/consequences andMSolutions
The yellow!warning lamp lights up. The red F(USAonly)
or ! (Canada only) indicator lamp flashes for about te nseconds
after th eelectric parking brak ehas been applie dor released. It then
goe sout or remain slit .
The electric parking brak eis malfunctioning .
XSwitchoff th eignition and tur nit bac kon .
XApply th eelectric parking brake.
If it is no tpossibl eto engage th eelectric parking brake:
XShift th etransmission to position j.
XVisitaqualified specialist workshop .
If it is no tpossibl eto release th eelectric parking brak emanually:
XReleas eth eelectric parking brak eautomatically (Ypage 150).
If th eelectric parking brak estill canno tbe released:
XConsult aqualified specialist workshop .
The yellow!warning lamp lights up. If you manually apply or
release th eelectric parking brake, th ered F (USAonly) or !
(Canada only) indicator lamp flashes .
The electric parking brak eis malfunctioning .It is no tpossibl eto apply
th eelectric parking brak emanually.
XShift th etransmission to position j,as th eelectric parking brak e
is no tapplie dautomatically.
XVisit aqualified specialist workshop .
If it is no tpossibl eto release th eelectric parking brak emanually:
XReleas eth eelectric parking brak eautomatically (Ypage 150).
F(USA
only)
!(Canada
only)
Parkin gBrake Inop‐
erativ e
The yellow !warning lamp lights up. The red F(USAonly)
or ! (Canada only) indicator lamp flashes for about te nseconds
after th eelectric parking brak ehas been applie dor released. It then
goe sout or remain slit .
The electric parking brak eis malfunctioning ,e.g. because of over-
voltag eor undervoltage.
XRemove th ecaus efor th eovervoltage or undervoltage, e.g. by
charging th ebattery or restarting th eengine.
XEngage or release th eelectric parking brake.
If it remain simpossible to apply or release th eelectric parking brake:
XSwitc hoff th eignition and tur nit bac kon .
XEngage or release th eelectric parking brake.
If th eelectric parking brak estill canno tbe released:
XConsult aqualified specialist workshop .
If th eelectric parking brak estill canno tbe applied:
XVisit aqualified specialist workshop .
Display messages221
On-board computer and displays
Z

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 j.
XVisitaqualified specialist workshop .
$(USAonly)
J(Canada only)
Check Brake Fluid
Level
There is no tenough brak efluid in th ebrak efluid reservoir .
In addition ,th e$ (USAonly) or J(Canada only) warning lamp
lights up in th einstrumen tcluste rand awarning tone sounds.
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 147).
XConsult aqualified specialist workshop .
XDo notadd brak efluid .This does no tcorrec tth emalfunction .
#
CheckBrakePadWear
The brak epads/linings hav ereached their wear limit.
US Aonly: th e$ red brak esystem warning lamp is lit while th e
engin eis running.
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:
RThe radar sensor system is temporarily inoperative, e.g. due to
electromagneti cradiation emitted by nearby TV or radi ostation sor
other source sof electromagneti cradiation .
RThe system is outside th eoperating temperature range.
RThe on-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 147).
XRestart th eengine.
222Display messages
On-board computer and displays

Display messagesPossible causes/consequences andMSolutions
RadarSensorsDirtySee Operator' sMan ‐ual
The radar sensor system is malfunctioning .
Possibl ecauses are:
RDirt on sensor s
RHeavy rain or snow
RWhendrivin gon inter-urban roads without traffic or infrastructure,
e.g. in desert-like area s
At least on edrivin gsystem or drivin gsafet ysystem is malfunctioning
or is temporarily unavailable :
RActive Brake Assistwit hcross-traffic function
RActive Brake Assis t
RActive LaneKeepin gAssis t
RActive Blind Spot Assis t
RDistancePilo tDISTRONI Cwit hSteering Pilo t
If th eradar sensor system in fron tis dirty, Active Blind Spot Assis twill
no tperfor m acourse-correcting brak eapplication .
Once th ecaus eof th eproblem is no longer present, th edrivin gand
drive safet ysystems will be available again .The display message dis-
appears.
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 147).
XSwitchoff th eengine.
XClean all sensor s (Ypage 295).
XRestart theengine.
The display message disappears.
6
SRSMalfunctionSer ‐viceRequired
The restrain tsystem is malfunctioning .The 6 warning lamp also
lights up in th einstrumen tcluster.
GWARNIN G
The air bags or Emergency Tensioning Devices may either be triggered
unintentionally or, in th eevent of an accident, may no tbe triggered .
There is an increased ris kof injury.
XVisit aqualified specialist workshop immediately.
Fo rfurther information about th erestrain tsystem, see (
Ypage 43).
6
Front Lef tMalfunc‐tio nServic eRequiredorFrontRight MalfunctionServic eRequired
The restrain tsystem is malfunctioning at th efron ton th elef tor right .
The 6 warning lamp also lights up in th einstrumen tcluster.
GWARNIN G
The air bags or Emergency Tensioning Devices may either be triggered
unintentionally or, in th eevent of an accident, may no tbe triggered .
There is an increased ris kof injury.
XVisit aqualified specialist workshop immediately.
224Display messages
On-board computer and displays

Display messagesPossible causes/consequences andMSolutions
6
RearLef tMalfunc‐tio nServic eRequiredorRea rRight MalfunctionServic eRequired
The rear left-han dor right-hand restrain tsystem is malfunctioning .
The 6 warning lamp also lights up in th einstrumen tcluster.
GWARNIN G
The air bags or Emergency Tensioning Devices may either be triggered
unintentionally or, in th eevent of an accident, may no tbe triggered .
There is an increased ris kof injury.
XVisit aqualified specialist workshop immediately.
6
Lef tSid eCurtai nAirbag MalfunctionServiceRequiredor
Right Sid eCurtai n
Airbag MalfunctionServiceRequired
The left-han dor right-hand window curtai nair bag is malfunctioning .
The 6 warning lamp also lights up in th einstrumen tcluster.
GWARNIN G
The lef tor right window curtai nair bag may either be triggered unin-
tentionally or, in th eevent of an accident, may no tbe triggered .
There is an increased ris kof injury.
XVisit aqualified specialist workshop immediately.
Display messages22 5
On-board computer and displays
Z

Display messagesPossible causes/consequences andMSolutions
XVisitaqualified specialist workshop immediately.
Fo rfurther information about th eOccupant Classification System, see
(
Ypage 52).
Lights
Display messagesPossible causes/consequences and MSolutions
b
CheckLeftLowBeam(Example)
The bulb in question is malfunctioning .
XVisitaqualified specialist workshop .
or
XChec kwhether you are permitte dto replace th ebulb yourself
(Ypage 112).
iLE Dligh tsources: th edisplay message for th ecorrespondin g
lamp only appear swhen all th eLEDs in th elamp hav efailed.
b
Active HeadlampsInoperative
The active ligh tfunction is malfunctioning .
XVisitaqualified specialist workshop .
b
Malfunction SeeOperator’sManual
The exterio rlighting is malfunctioning .
XVisitaqualified specialist workshop .
b
AutoLam pFunctionInoperative
The ligh tsensor is malfunctioning .
XVisitaqualified specialist workshop .
b
Switch Off Lights
You leaveth evehicl eand th elights are switched on . Awarning tone
also sounds.
XTurn th eligh tswitch to th eà position .
b
Switch On Headlamps
You are drivin gwit hlow-beam headlamp sswitched off .
XTurn theligh tswitch to th eL orà position .
228Display messages
On-board computer and displays

Safety
Seat belts
Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
üNAfter starting the engine, the red seat belt warning lamp lights up for six sec-
onds.
The seat belt warning lamp reminds the driver and front passenger to fasten their
seat belts.
XFasten your seat belt (Ypage 47).
üN After starting the engine, the red seat belt warning lamp lights up. In addition, a
warning tone sounds for up to six seconds.
The driver's seat belt is not fastened.
XFasten your seat belt (Ypage 47).
The warning tone ceases.
üN The red seat belt warning lamp lights up after the engine starts, as soon as the
driver's or the front-passenger door is closed.
The driver or front passenger has not fastened their seat belt.
XFasten your seat belt (Ypage 47).
The warning lamp goes out.
There are objects on the front-passenger seat.
XRemove the objects from the front-passenger seat and stow them in a secure
place.
The warning lamp goes out.
üN The red seat belt warning lamp flashes and an intermittent audible warning
sounds.
The driver or front passenger has not fastened their seat belt. The vehicle is being
driven faster than 15 mph (25 km/h) or has briefly been driven faster than 15 mph
(25 km/h).
XFasten your seat belt (Ypage 47).
The warning lamp goes out and the intermittent warning tone ceases.
There are objects on the front-passenger seat. The vehicle is being driven faster
than 15 mph (25 km/h) or has briefly been driven faster than 15 mph (25 km/h).
XRemove the objects from the front-passenger seat and stow them in a secure
place.
The warning lamp goes out and the intermittent warning tone ceases.
Warning and indicator lamps in the instrument cluster245
On-board computer and displays
Z

Safety systems
Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
$JN$ (USA only), J(Canada only): the red brake system warning lamp is lit
while the engine is running.
A warning tone also sounds.
GWARNING
The brake boosting effect is malfunctioning and the braking characteristics may be
affected.
There is a risk of an accident.
XPull over and stop the vehicle safely as soon as possible, paying attention to road
and traffic conditions. Do not continue driving under any circumstances.
XSecure the vehicle against rolling away (Ypage 147).
XConsult a qualified specialist workshop.
XObserve the additional display messages in the multifunction display.
$JN $ (USA only), J(Canada only): the red brake system warning lamp lights
up while the engine is running.
A warning tone also sounds.
There is not enough brake fluid in the brake fluid reservoir.
GWARNING
The braking effect may be impaired.
There is a risk of an accident.
XPull over and stop the vehicle safely as soon as possible, paying attention to road
and traffic conditions. Do not continue driving under any circumstances.
XSecure the vehicle against rolling away (Ypage 147).
XDo not add brake fluid. Adding more will not correct the malfunction.
XConsult a qualified specialist workshop.
XObserve the additional display messages in the multifunction display.
$N USA only: the red brake system warning lamp is lit while the engine is running.
The multifunction display also shows a display message with the #symbol.
The brake pads/linings have reached their wear limit.
XVisit a qualified specialist workshop.
246Warning and indicator lamps in the instrument cluster
On-board computer and displays

Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
F!NF (USA only), !(Canada only): the red indicator lamp for the electric
parking brake flashes or is lit and/or the yellow warning lamp for the electric
parking brake is lit.
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 43).
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.
In 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 require-
ments in effect in these states. If in doubt, check whether such legal regulations
apply in the state in which you are currently driving.
8N 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.
250Warning and indicator lamps in the instrument cluster
On-board computer and displays

Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
8NThe 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 gauge 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 147).
XConsult a qualified specialist workshop.
Warning and indicator lamps in the instrument cluster251
On-board computer and displays
Z

Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
XIf the coolant temperature is below the red marking, drive to the nearest quali-
fied specialist workshop.
XAvoid heavy loads on the engine as you do so, e.g. driving in mountainous terrain
and stop-and-go traffic.
Driving systems
Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
·NThe red distance warning lamp lights up while the vehicle is in motion. A warning
tone also sounds.
You are approaching a vehicle, a pedestrian or a stationary obstacle in your line of travel at too high a speed.
XBe prepared to brake immediately.
XPay careful attention to the traffic situation. You may have to brake or take
evasive action.
Further information about Active Brake Assist with cross-traffic function
(
Ypage 70).
Further information on the distance warning function of Active Brake Assist
(
Ypage 64).
Warning and indicator lamps in the instrument cluster253
On-board computer and displays
Z