air condition MERCEDES-BENZ C-CLASS CABRIOLET 2018 Service Manual

Display messagesPossible causes/consequences andMSolutions
CThere is onlyaver ysmall amount of fuel in th efuel tank.
XRefue lat th eneares tgas station without fail .
8
Gas Cap Loose
The fuel filler cap is notclosed correctl yor th efuel system is leaking .
XCheckthat th efuel filler cap is correctl yclosed .
If th efuel filler cap is not correctl yclosed :
XCloseth efuel filler cap .
If th efuel filler cap is correctl yclosed :
XVisitaqualified specialist workshop .
Driving systems
Display messagesPossible causes/consequences and MSolutions
À
ATTENTION ASSIST:Take a Break!
Based on certain criteria, ATTENTION ASSIST has detecte dfatigue or
a lack of concentration on th epart of th edriver . Awarning tone also
sounds.
XIf necessary, tak e abreak.
During lon gjourneys, tak eregular breaks in goo dtime so you get
enough rest.
À
ATTENTION ASSISTInoperative
ATTENTION ASSIST is inoperative.
XVisit aqualified specialist workshop .
¨
VehicleRising
The vehicl eis rising to th elevel you hav eselected.
¨
Vehicl eRisingPlease Wai t
The vehiclelevel is to olow when th evehicl eis stationary. Awarning
tone also sounds.
XDo no tpull away.
The vehicl elevel is set when th edisplay message disappears.
¨
Sto pVehicl eVehi‐cle Too Low
You hav epulled away while th evehicl elevel is still to olow.
AIRMATIC set sth evehicl eto th eselected level after ashort period.
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).
XWait until th edisplay message disappear sbefore pullin gaway.
228Display 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
TrafficSignAssistCurrently Unavaila‐ble See Operator' sManual
Traffic SignAssis tis 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, th edisplay
message disappears.
Traffic Sig nAssis tis operational again .
TrafficSignAssistInoperativeTraffic Sig nAssis tis malfunctioning .
XVisitaqualified specialist workshop .
ë
Off
The HOLD function is deactivated. The vehicl eis skidding.
A warning tone also sounds.
XReactivat eth eHOLD function later (Ypage 162).
The HOLD function is deactivated. Whe nth ebrak epedal is firmly
depressed, an activation condition is no tfulfilled .
A warning tone also sounds.
XChec kth eactivation condition sfor th eHOLD function
(Ypage 161).
Distance Pilot OffDistanc ePilo tDISTRONI Cis deactivated (Ypage 158).
If it was no tdeactivated by th edriver , awarning tone also sounds.
Distance Pilot NowAvailableDistanc ePilo tDISTRONI Cis operational again after having been tem-
porarily unavailable .You can no wreactivat eDistanc ePilo t
DISTRONI C (
Ypage 155).
Distance Pilot Cur ‐rently UnavailableSee Operator'sMan ‐ual
Distanc ePilo tDISTRONI Cis temporarily inoperative.
Steering Pilo tis also 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.
A warning tone also sounds.
Whe nth ecauses state dabov eno longer apply, th edisplay message
disappears.
Distanc ePilo tDISTRONI Cis 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).
XRestart th eengine.
Display messages23 1
On-board computer and displays
Z

Display messagesPossible causes/consequences andMSolutions
DistancePilotInop‐erativeDistanc ePilo tDISTRONI Cis malfunctioning .
The followin gmay hav ealso failed:
RActive Brake Assis twit hcross-traffic function
RSteering Pilo t
A warning tone also sounds.
XVisit aqualified specialist workshop .
Distance Pilot Sus‐pendedYou havedepressed th eaccelerato rpedal .Distanc ePilo tDISTRONI C
is no longer controllin gth espeed of th evehicle.
XRemove your foo tfrom th eaccelerato rpedal .
Distance Pilot- - - mphAcondition for activating Distanc ePilo tDISTRONI Chas no tbeen met .
XCheckth eactivation condition sfor Distanc ePilo tDISTRONI C
(Ypage 155).
Steering Pilot Cur ‐rently UnavailableSee Operator'sMan ‐ual
Steering Pilo tis 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.
Steering Pilo 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.
SteeringPilotInop‐erativ eSteering Pilo tis malfunctioning .
However, th eDistanc ePilo tDISTRONI Cfunction sare still available.
A warning tone also sounds.
XVisit aqualified specialist workshop .
CruiseControlInop‐erativeCruisecontrol is malfunctioning .
A warning tone also sounds.
XVisit aqualified specialist workshop .
232Display messages
On-board computer and displays

Tires
Display messagesPossible causes/consequences andMSolutions
CheckTirePressureSoonCanada only:
The tire pressure loss warning system has detected a significant loss
in pressure.
A warning tone also sounds.
Possible causes:
Ryou have changed the positions of the wheels and tires or installed
new wheels and tires
Rthe tire pressure in one or more tires has dropped significantly
GWARNING
Tire pressures that are too low pose the following hazards:
Rthey may burst, especially as the load and vehicle speed increase.
Rthey may wear excessively and/or unevenly, which may greatly
impair tire traction.
Rthe driving characteristics, as well as steering and braking, may be
greatly impaired.
There is a risk of an accident.
XStop the vehicle without making any sudden steering or braking
maneuvers. Pay attention to the traffic conditions as you do so.
XSecure the vehicle against rolling away (Ypage 143).
XCheck the tires and, if necessary, follow the instructions for a flat
tire (Ypage 296).
XCheck the tire pressures and, if necessary, correct the tire pressure.
XRestart the tire pressure loss warning system when the tire pres-
sure is correct (Ypage 319).
CheckTirePressureThen Restart RunFlat Indicator
Canada only:
The tire pressure loss warning system generated a display message
and has not been restarted since.
XSet the correct tire pressure in all four tires.
XRestart the tire pressure loss warning system (Ypage 319).
Run Flat IndicatorInoperativeCanada only:
The tire pressure loss warning system is faulty.
XVisit a qualified specialist workshop.
PleaseCorrectTirePressureThe tire pressure is too low in at least one of the tires, or the tire
pressure difference between the wheels is too great.
XCheck the tire pressures at the next opportunity (Ypage 321).
XIf necessary, correct the tire pressure.
XRestart the tire pressure monitor (Ypage 321).
234Displa y messages
On-board computer and displays

Display messagesPossible causes/consequences andMSolutions
Check TiresThe tire pressurein on eor mor etires has dropped significantly. The
whee lposition is displayed in th emultifunction display.
A warning tone also sounds.
GWARNIN G
Tir epressures that are to olow pos eth efollowin ghazards :
Rthey may burst, especially as th eload and vehicl espeed increase.
Rthey may wear excessivel yand/o runevenly, whic hmay greatl y
impair tire traction .
Rthedrivin gcharacteristics ,as well as steering and braking ,may be
greatl yimpaired.
There is aris kof an accident.
XStop th evehicl ewithout making any sudden steering or braking
maneuvers .Pay attention to th etraffic condition sas you do so.
XSecur eth evehicl eagainst rollin gaway (Ypage 143).
XCheckth etires and ,if necessary, follow th einstruction sfor aflat
tire (Ypage 296).
XChec kth etire pressur e (Ypage 321).
XIf necessary, correc tth etire pressure.
Warnin gTir eMal ‐functionThe tire pressur ein on eor mor etires has dropped suddenly. The whee l
position is shown in th emultifunction display.
GWARNIN G
Drivin gwit h a flat tire poses aris kof th efollowin ghazards :
Raflat tire affects th eabilit yto steer or brak eth evehicl e
Ryou could lose control of th evehicl e
Rcontinued drivin gwit h a flat tire will caus eexcessive heat build-up
and possibl y afire
There is aris kof an accident.
XStop th evehicl ewithout making any sudden steering or braking
maneuvers .Pay attention to th etraffic condition sas you do so.
XSecur eth evehicl eagainst rollin gaway (Ypage 143).
XCheckth etires and ,if necessary, follow th einstruction sfor aflat
tire (Ypage 296).
TirePress.Monito rCurrently Unavaila‐ble
Becausethere is interferenc efrom astron gsource of radi owaves, no
signals from th etire pressur esensor sare detected. The tire pressur e
monitor is temporarily malfunctioning .
XDrive on.
The tire pressur emonitor restarts automatically as soo nas th e
problem has been resolved.
TirePress .Sen ‐sor(s) Missin gThere is no signal from th etire pressur esensor of on eor several tires .
The pressur eof th eaffecte dtire is no tdisplayed in th emultifunction
display.
XHav eth efault ytire pressur esensor replace dat aqualified special -
ist workshop .
Display messages235
On-board computer and displays
Z

Display messagesPossible causes/consequences andMSolutions
StopVehicl eLeaveEngineRunnin gWaitTransmission Cool‐ing
The transmission has overheated. Pullin gaway can be temporarily
impaire dor no tpossible.
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.
NThe trunk lid is open .
XCloseth etrunk lid.
MThe hoo dis open . Awarning tone also sounds.
GWARNIN G
The open hoo dmay bloc kyour vie wwhen th evehicl eis in motion .
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.
XSecur eth evehicl eagainst rollin gaway (Ypage 143).
XCloseth ehood.
CAt least on edoor is open . Awarning tone also sounds.
XClos eall th edoors.
_
Front Lef tSea tBackrestNotLockedorFront Right Sea tBackrest Not Locked
The driver's or fron tpassenger's seat backrest is no tengaged. A
warning tone also sounds.
XPush th ebackrest bac kuntil it engages.
Ð
Power Steering Mal ‐function See Opera‐tor's Manual
The powersteering is malfunctioning .
A warning tone also sounds.
GWARNIN G
You will need to use mor eforce to steer .
There is aris kof an accident.
XChec kwhether you are able to apply th eextr aforce required.
If you ar eabl eto steer safely:
XDrive on carefully.
XVisit aqualified specialist workshop immediately.
If you ar eunable to steer safely:
XDo no tdrive on .
XConsult aqualified specialist workshop .
238Display messages
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
?NThe red coolant warning lamp comes on while the engine is running.
The coolant level is too low.
If the coolant level is correct, the airflow to the engine radiator may be blocked or
the electric engine radiator fan may be defective.
The coolant is too hot and the engine is no longer being cooled sufficiently.
XObserve the additional display messages in the multifunction display.
XPull over and stop the vehicle safely and switch off the engine, paying attention
to road and traffic conditions.
XSecure the vehicle against rolling away (Ypage 143).
XLeave the vehicle and keep a safe distance from the vehicle until the engine has cooled down.
XCheck the coolant level and add coolant, observing the warning notes
(Ypage 284).
XIf you have to add coolant frequently, have the engine cooling system checked.
XMake sure that the air supply to the engine radiator is not blocked, e.g. by snow,
slush or ice.
XDo not start the engine again until the coolant temperature gauge is below the
red marking. Otherwise, the engine could be damaged.
XDrive to the nearest qualified specialist workshop.
XAvoid heavy loads on the engine as you do so, e.g. driving in mountainous terrain
and stop-and-go traffic.
?N The red coolant warning lamp comes on while the engine is running. A warning
tone also sounds.
The coolant temperature gauge has reached the red marking. The airflow to the
engine radiator may be blocked or the coolant level may be too low.
GWARNING
The engine is not being cooled sufficiently and may be damaged.
Do not drive when your engine is overheated. This can cause some fluids which
may have leaked into the engine compartment to catch fire.
Steam from the overheated engine can also cause serious burns which can occur
just by opening the hood.
There is a risk of injury.
XObserve the additional display messages in the multifunction display.
XPull over and stop the vehicle safely and switch off the engine, paying attention
to road and traffic conditions.
XSecure the vehicle against rolling away (Ypage 143).
XLeave the vehicle and keep a safe distance from the vehicle until the engine has
cooled down.
XCheck the coolant level and add coolant, observing the warning notes
(Ypage 284).
XIf you have to add coolant frequently, have the engine cooling system checked.
XMake sure that the air supply to the engine radiator is not blocked, e.g. by snow,
slush or ice.
Warning and indicator lamps in the instrument cluster249
On-board computer and displays
Z

Tires
Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
hNThe yellow tire pressure monitor warning lamp (pressure loss/malfunction) is lit.
The tire pressure monitor has detected a loss of pressure in at least one of the tires.
GWARNING
Tire pressures that are too low pose the following hazards:
Rthey may burst, especially as the load and vehicle speed increase
Rthey may wear excessively and/or unevenly, which may greatly impair tire trac-
tion
Rthe driving characteristics, as well as steering and braking, may be greatly
impaired
There is a risk of an accident.
XStop the vehicle without making any sudden steering or braking maneuvers. Pay
attention to the traffic conditions as you do so.
XSecure the vehicle against rolling away (Ypage 143).
XObserve the additional display messages in the multifunction display.
XCheck the tires and, if necessary, follow the instructions for a flat tire
(Ypage 296).
XCheck the tire pressure (Ypage 321).
XIf necessary, correct the tire pressure.
hN The yellow tire pressure monitor warning lamp (pressure loss/malfunction)
flashes for approximately one minute and then remains lit.
The tire pressure monitor is malfunctioning.
GWARNING
The system is possibly unable to recognize or register low tire pressure.
There is a risk of an accident.
XObserve the additional display messages in the multifunction display.
XVisit a qualified specialist workshop immediately.
Warning and indicator lamps in the instrument cluster251
On-board computer and displays
Z