2018 MERCEDES-BENZ C-CLASS CABRIOLET warning light

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
There is amalfunction in th eleft-han dand/o rright-hand head bag.
The 6 warning lamp also lights up in th einstrumen tcluster.
GWARNIN G
The lef tor right head bag 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.
A
MalfunctionServic eRequired
GWARNIN G
The rol lbars are defective.
XVisit aqualified specialist workshop immediately.
Display messages22 1
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 .
iLEDligh 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 .
Adaptive HighbeamAssist CurrentlyUnavailable SeeOperator' sManual
Adaptive Highbea mAssis tis deactivated and temporarily inoperative.
Possibl ecauses are:
RThe windshield in th ecamera' sfield of vision is dirty.
RVisibilit yis impaire ddue to heav yrain ,snow or fog .
XClean thewindshield.
If th esystem detects that th ecamera is full yoperational again ,th e
Adaptive
HighbeamAssistNowAvailablemessage is displayed.
Adaptive Highbea mAssis tis operational again .
Adaptive HighbeamAssist InoperativeAdaptive HighbeamAssis tis malfunctioning .
XVisitaqualified specialist workshop .
224Display messages
On-board computer and displays

Display messagesPossible causes/consequences andMSolutions
#
See Operator'sMan ‐ual
The battery is no tbein gcharged.
A warning tone also sounds.
Possibl ecauses are:
Radefective alternato r
Ratorn poly-V-belt
Ramalfunction in th eelectronics
!Do no tcontinu edriving. The engin ecould otherwise overheat.
XPull ove rand stop th evehicl esafely and switch off th eengine, pay-
ing attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 143).
XConsult aqualified specialist workshop .
#
StopVehicl eSeeOperator' sManual
The battery is no longer bein gcharged and th econdition of charg eis
to olow.
A warning tone also sounds.
XPull ove rand stop th evehicl esafely and switch off th eengine, pay-
ing attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 143).
XObserv eth einstruction sin th e# See Operator' sManualdisplay message .
XConsultaqualified specialist workshop .
#
StopVehicl eLeaveEngine Runnin g
The battery condition of charg eis to olow.
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.
XLeav eth eengin erunning.
XWait until th edisplay message disappear sbefore pullin gaway.
#
Start Engine SeeOperator' sManual
The engin eis switched off and th econdition of charg eis to olow.
XSwitc hoff electrical consumer sthat you do no tneed, suc has th e
rear window defroste rand interior lighting .
XLeaveth eengin erunnin gfor afew minute sor drive alon gdistance.
The battery is bein gcharged.
226Display messages
On-board computer and displays

Display messagesPossible causes/consequences andMSolutions
AIRMATIC is malfunctioning. Awarning tone also sounds.
XDo no tdrive at speeds abov e50 mph (80 km/h).
XMak eonly slight steering movements. Otherwise ,th efron tfender
or th etires could be damaged if th esteering movement is to olarge.
XListe nfor scraping sounds.
XPull ove rand stop th evehicl esafely, payin gattention to roa dand
traffic conditions, and set ahigher vehicl elevel.
Dependin gon th emalfunction ,it may be possibl eto rais eth evehi-
cle .
XVisit aqualified specialist workshop .
¨
Malfunction
The AIRMATIC function is restricted. The vehicle's handlin gcharac -
teristics may be affected.
XDo no tdrive at speeds abov e50 mph (80 km/h).
XVisit aqualified specialist workshop .
LaneKeepin gAssistCurrently Unavaila‐ble See Operator' sManualorActiveLan eKeepin gAssistCurrently Unavaila‐ble See Operator' sManual
LaneKeepin gAssis tor Active Lan eKeepin gAssis tis deactivated and
temporarily inoperative.
Possibl ecauses are:
RThe windshield in th ecamera' sfield of vision is dirty.
RVisibilit yis impaire ddue to heav yrain ,snow or fog .
RThere havebeen no lan emarking sfor an extended period
RThe lan emarking sare wor naway, dark or covered up, e.g. by dir tor
snow.
Whe nth ecauses state dabov eno longer apply, th edisplay message
disappears.
Lan eKeepin gAssis tor Active Lan eKeepin gAssis 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 143).
XClean th ewindshield.
Lan eKeepin gAssistInoperativeor
ActiveLan eKeepin gAssist Inoperative
LaneKeepin gAssis tor Active Lan eKeepin gAssis tis malfunctioning .
XVisitaqualified specialist workshop .
Display messages229
On-board computer and displays
Z

Display messagesPossible causes/consequences andMSolutions
Becausethere is interferenc efrom astron gsource of radi owaves, th e
SmartKey is no tdetecte dwhils tth eengin eis running.
A warning tone also sounds.
XPull ove rand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XSecur eth evehicl eagainst rollin gaway (Ypage 143).
XInsertth eSmartKey int oth eignition loc kand drive in SmartKey
mode.
Â
Remove 'Start 'But ‐ton and Insert Key
The SmartKey is continually undetected.
The SmartKey detection function has atemporar ymalfunction or is
faulty. Awarning tone also sounds.
XInser tth eSmartKey int oth eignition loc kand tur nit to th edesire d
position .
XVisitaqualified specialist workshop .
Warning and indicat orlamps in the instrume nt cluster
General notes
Some systems carry out aself-diagnosis when th eignition is switched on .Therefore ,som eindicator
and warning lamp smay ligh tup or flas htemporarily. This behavio ris non-critical .These indicator
and warning lamp sonly indicat e amalfunction if they ligh tup or flas hafter starting th eengin eor
whils tdriving.
Safety
Seat belts
Warning/
indicator
lam pNSignal type
Possible causes/consequences and M
Solutions
üNAfte rstarting th eengine, th ered seat belt warning lamp lights up for six sec -
onds.
The seat belt warning lamp remind sth edriver and fron tpassenger to faste ntheir
seat belts.
XFaste nyour seat belt (Ypage 47).
üNAfte rstarting th eengine, th ered seat belt warning lamp lights up. In addition , a
warning tone sounds for up to six seconds.
The driver's seat belt is no tfastened.
XFaste nyour seat belt (Ypage 47).
The warning tone ceases .
Warning and indicator lamps in the instrument cluster241
On-board computer and displays
Z

Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
üNThe 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.
242Warning and indicator lamps in the instrument cluster
On-board computer and displays

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 143).
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 143).
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.
Warning and indicator lamps in the instrument cluster243
On-board computer and displays
Z

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.
Warning and indicator lamps in the instrument cluster247
On-board computer and displays
Z