MERCEDES-BENZ C-CLASS CABRIOLET 2018 Owner's Manual

Display messagesPossible causes/consequences andMSolutions
Phone No ServiceYour vehicleis outside th enetwork provider' stransmitter/receiver
range.
XWait until th emobile phone operational readiness symbol appear s
in th emultifunction display.
J
TrunkPartitionOpe n
The trunk partition is open .
XCloseth etrunk partition (Ypage 90).
K
While stationary,apply the brakesbefore operatingthe softtop .
The vehicl eis stationary and you tr yto open or close th esof ttop.
XDepress th ebrak epedal .
XPush or pull th esof tto pswitch again until th esof tto pis full yopen
or closed (Ypage 89).
K
Convertible TopOperation Possibleto 35 mph
If you drive at speeds of mor ethan 35 mph (60 km/h), you canno t
open or close th esof ttop.
XDo no tdrive at speeds abov e35 mph (60 km/h).
XFull yopen or close th esof tto p (Ypage 89) .
K
ConvertibleTopLow‐ering
The sof tto pis no tfully opened or closed .The hydraulic sare depres-
surized.
XFull yopen or close th esof tto p (Ypage 89).
K
Open/Clos eConver ‐tibleTopCompletel y
The roofis no tlocked.
If you drive at speeds of mor ethan 35 mph (60 km/h), you canno t
open or close th esof ttop.
XPull ove rand stop th evehicl esafely as soo nas possible, payin g
attention to roa dand traffic conditions.
XPush or pull and hold th esoft-to pswitch until th esof tto pis full y
open or closed (Ypage 89).
K
Start Engine SeeOperator'sManual
The on-boar dvoltag eis to olow.
XStart th eengine.
¥
Check Washer Fluid
The washer flui dlevel in th ewasher flui dreservoir has dropped belo w
th eminimum .
XAddwasher flui d (Ypage 285).
Display messages239
On-board computer and displays
Z

SmartKey
Display messagesPossible causes/consequences andMSolutions
Â
KeyDoesNotBelongto Vehicle
You have put the wrong SmartKey in the ignition lock.
XUse the correct SmartKey.
Â
Take Your Key fromIgnition
The SmartKey is in the ignition lock.
A warning tone sounds
XRemove the SmartKey.
Â
Obtain a New Key
The SmartKey needs to be replaced.
XVisit a qualified specialist workshop.
Â
Replace Key Battery
The SmartKey battery is discharged.
XChange the batteries (Ypage 79).
Â
Don't Forget YourKey
The SmartKey is not in the ignition lock. You have opened the driver's
door with the engine switched off. A warning tone sounds
This display message is displayed for a maximum of 60 seconds and is
simply a reminder.
XTake the SmartKey with you when you leave the vehicle.
Â
Key Not Detected(white display message)
The SmartKey is currently undetected.
XChange the location of the SmartKey in the vehicle.
If the SmartKey still cannot be detected:
XInsert the SmartKey into the ignition lock and turn it to the desired position.
Â
Key Not Detected(red display message)
The SmartKey is not in the vehicle.
A warning tone also sounds.
If the engine is switched off, you can no longer lock the vehicle cen-
trally or start the engine.
XPull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
XSecure the vehicle against rolling away (Ypage 143).
XLocate the SmartKey.
XPress aon the steering wheel to confirm the display message.
240Display messages
On-board computer and displays

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
!NThe yellow ABS warning lamp is lit while the engine is running.
ABS (anti-lock braking system) is malfunctioning.
If there is an additional warning tone, the EBD (electronic brake force distribution)
is malfunctioning.
Other driving systems and driving safety systems may also malfunction.
GWARNING
The brake system continues to function normally, but without the functions listed
above. The front and rear wheels could therefore lock if you brake hard, for exam-
ple.
The steerability and braking characteristics may be severely affected. The braking
distance in an emergency braking situation can increase.
If ESP
®is not operational, ESP®is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
XObserve the additional display messages in the multifunction display.
XDrive on carefully.
XVisit a qualified specialist workshop immediately.
If the ABS control unit is faulty, there is also a possibility that other systems, such
as the navigation system or the automatic transmission, will not be available.
$J
÷!N $ (USA only), J(Canada only): the red brake warning lamp and the yellow
ESP®and ABS warning lamps are lit while the engine is running.
ABS and ESP®are malfunctioning.
Other driving systems and driving safety systems may also malfunction.
GWARNING
The brake system continues to function normally, but without the functions listed
above. The front and rear wheels could therefore lock if you brake hard, for exam-
ple.
The steerability and braking characteristics may be severely affected. The braking
distance in an emergency braking situation can increase.
If ESP
®is not operational, ESP®is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
XObserve the additional display messages in the multifunction display.
XDrive on carefully.
XVisit a qualified specialist workshop immediately.
244Warning and indicator lamps in the instrument cluster
On-board computer and displays

Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
÷NThe yellow ESP®warning lamp flashes while the vehicle is in motion.
ESP®or traction control has intervened because there is a risk of skidding or at
least one wheel has started to spin.
Cruise control or Distance Pilot DISTRONIC is deactivated.
XWhen pulling away, only depress the accelerator pedal as far as necessary.
XEase off the accelerator pedal while the vehicle is in motion.
XAdapt your driving style to suit the road and weather conditions.
XDo not deactivate ESP®.
In exceptional cases, it may be better to deactivate ESP®:
Rwhen using snow chains
Rin deep snow
Ron sand or gravel
Observe the important safety notes on ESP®(Ypage 68).
÷N The yellow ESP®warning lamp is lit while the engine is running.
ESP®is malfunctioning.
Other driving systems and driving safety systems may also malfunction.
GWARNING
The brake system continues to function normally, but without the functions listed
above.
The braking distance in an emergency braking situation can thus increase.
If ESP
®is not operational, ESP®is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
XObserve the additional display messages in the multifunction display.
XDrive on carefully.
XVisit a qualified specialist workshop immediately.
Warning and indicator lamps in the instrument cluster245
On-board computer and displays
Z

Warning/
indicator
lampNSignal type
Possible causes/consequences and M
Solutions
åNThe yellow ESP®OFF warning lamp is lit while the engine is running or the ECO
start/stop function is activated.
ESP
®is deactivated.
GWARNING
If ESP
®is switched off, ESP®is unable to stabilize the vehicle.
Further driving systems or driving safety systems are thus restricted, e.g. Active
Blind Spot Assist. The system does not perform braking actions.
There is an increased risk of skidding and an accident.
XReactivate ESP®.
In exceptional cases, it may be better to deactivate ESP®:
Rwhen using snow chains
Rin deep snow
Ron sand or gravel
Observe the important safety notes on ESP®(Ypage 68).
XAdapt your driving style to suit the road and weather conditions.
If ESP
®cannot be activated:
XDrive on carefully.
XContact a qualified specialist workshop and have ESP®checked.
MN Mercedes-AMG vehicles:
The yellow SPORT handling mode warning lamp is lit while the engine is running.
SPORT handling mode is activated.
GWARNING
When SPORT handling mode is switched on, ESP
®is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
XOnly activate SPORT handling mode in accordance with the conditions descri-
bed in the "Activating/deactivating ESP®" section (Ypage 69).
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.
Warning and indicator lamps in the instrument cluster247
On-board computer and displays
Z

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 143).
XConsult a qualified specialist workshop.
248Warning and indicator lamps in the instrument cluster
On-board computer and displays