2021 MERCEDES-BENZ C-CLASS CABRIOLET check engine

Occupant saf
ety Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions
6 Re stra int sy stem warning
lamp *T
he redre stra int sy stem warning lamp is lit while the engine is running.
The restra int sy stem is malfunctioning (/ page 38). &
WARNING Risk of inju rydue tomalfunctions in there stra int sy stem
Components in there stra int sy stem may be activated unintentionally or not deploy as intended in an accident. #
Have there stra int sy stem checked and repaired immediately at a qualified specialist workshop. #
Drive on carefully. #
Notethe messages on the multifunction displa y. #
Consult a qualified specialist workshop immediatel y.
ü
Seat belt warning lamp *T
he red seat belt warning lamp flashes and an intermit tent wa rning tone sounds.
or
The red seat belt warning lamp lights up once the engine has star ted.
In addition, an intermittent warning tone may sound.
The red seat belt warning lamp flashes and an intermit tent wa rning tone sounds:
The driver or front passenger has not fastened his or her seat belt while theve hicle is in motion. #
Fasten your seat belt (/ page 42).
There are objects on the front passenger seat. Display messages and
warning/indicator lamps 487

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions
R The coolant pump is faulty
If th ere is an additional warning tone, the coolant temp erature has exceeded 120°C. &
WARNING Risk of bu rns when opening the bonn et
If yo u open the bonn etwhen the engine has overheated or when there is a fire inthe engine compartment, the
fo llowing situations may occur:
R You could come into contact with hot gases.
R You could come into contact with other hot, escaping operating fluids. #
Before opening the bonn et, allow the engine tocool down. #
Intheeve nt of a fire inthe engine compartment, keep the bonn etclosed and call thefire service. #
Stop theve hicle immediately in accordance with the traf fic conditions and switch off the engine. Do not continue
driving. #
Notethe messages on the multifunction displa y.
If th e coolant temp erature display is at the lo wer end of thete mp erature scale: #
Consult a qualified specialist workshop.
If th e coolant temp erature display is at the upper end of thete mp erature scale: #
Exit theve hicle and keep a safe dis tance from it until the engine has cooled down. #
Check the coolant le vel (/ page 361). 490
Display messages and warning/indicator lamps

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions #
Make sure that the air supply tothera diator is not obstructed. #
Avoiding high loads on the engine, drive tothe nearest qualified specialist workshop. In doing so, ensure that the
coolant temp erature display remains below 120°C.
; Engine diagnosis warning
lamp *T
he yellow engine diagno stics warning lamp is lit while the engine is running.
A malfunction has occu rred in the engine, theex haust sy stem or the fuel sy stem.
The emissions limit value may ha vebeen exceeded and the engine may be running in eme rgency operation mode. #
Have theve hicle checked as soon as possible at a qualified specialist workshop.
Ve hicles with a diesel engine: the fuel tank may ha vebeen run dr y. #
Start the engine thre eto four times af terre fuelling.
If th eye llow engine diagnosis warning lamp goes out, emer gency operation mode is cancelled. The vehicle need
not be checked.
#
Elect rical fault warning
lamp *T
hered elect rical fault warning lamp is lit.
There is a fault in the electrics. #
Notethe messages on the multifunction displa y. Displ
aymessa ges and warning/indicator lamps 491

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions
J Brake sy stem warning lamp
(yellow) *T
he yellow brake sy stem warning lamp is lit while the engine is running. &
WARNING Risk of an accident due toa brake sy stem malfunction
If th e brake sy stem is malfunctioning, braking characteristics may be impaired. #
Drive on carefull y. #
Have the brake sy stem checked immediately at a qualified specialist workshop. #
Adjust your speed and drive on carefull y,leaving a suitable dis tance totheve hicle in front. #
Ifth e multifunction display sho wsa display message, obse rve it. #
Consult a qualified specialist workshop.
J Brake sy stem warning lamp
(red) *T
he red brake sy stem warning lamp is lit while the engine is running.
Po ssible causes:
R The brake forc e boosting is malfunctioning and the braking characteristics may be af fected.
R The reis insuf ficient brake fluid in the brake fluid reser voir. #
Notethe messages on the multifunction displa y. &
WARNING Risk of accident and inju ryif brake forc e boosting is malfunctioning
If brake forc e boosting is malfunctioning, increased brake pedal forc e may be necessary for braking. The braking
ch aracteristics may be impaired. The braking dis tance can increase in emergency braking situations. Display messa
ges and warning/indicator lamps 493

Wa
rning/indicator lamp
Possible causes/consequences and M
MSolutions
The steerability and braking characteristics are heavily impaired and the braking dis tance may increase. In addi‐
tion, other driving saf ety sy stems are switched off. #
Drive on carefull y. #
Have the brake sy stem checked immediately at a qualified specialist workshop. ÷
ESP ®
wa rning lamp *
The yellow ESP ®
wa rning lamp flashes while theve hicle is in motion.
or
The yellow ESP ®
wa rning lamp is lit while the engine is running.
The yellow ESP ®
wa rning lamp flashes while theve hicle is in motion:
One or more wheels has reached its grip limit (/ page170). #
Adapt your driving style to suit thero ad and weather conditions.
The yellow ESP warning lamp ®
is lit while the engine is running.
ESP ®
is malfunctioning.
Other driving sy stems and driving saf ety sy stems (e.g. BAS) may also be malfunctioning. #
Notethe messages on the multifunction displa y. &
WARNING Risk of skidding if ESP ®
is malfunctioning
If ESP ®
is malfunctioning, ESP ®
cannot car ryout vehicle stabilisation. In addition, other driving saf ety sy stems
are switched off. 496
Display messages and warning/indicator lamps

City lighting
................................................ 124
Cleaning see Care
Climate control Activating/deactivating the A/C
function (cont rol panel)........................ .134
Ac tivating/deactivating the synchro‐
nisation function (cont rol panel)............ 13 4
Air-reci rculation mode.......................... .134
Au tomatic control.................................. 13 4
Demi sting the windscreen..................... 13 3
Demi sting windo ws............................... 13 4
Fr ont air vents....................................... 13 5
Ionisation............................................... 13 4
No te...................................................... 13 3
Re ar air vents....................................... .135
Setting the air distribution..................... 13 3
Setting the air flow ................................. 13 3
Setting theve hicle interior temp era‐
ture........................................................ 13 3
Switching on/of f................................... 13 3
Switching there ar wind owheater
on/off...................................................1 33
THERMATIC control pane l...................... 13 3
THERMOTRONIC contro l panel..............133 Ve
ntilating theve hicle (con venience
opening).................................................. 90
Co ckpit
Overview................................................... 6
Co ffee cup symbol
see ATTENTION ASSIST
Collision de tection (pa rked vehicle)
Information............................................ 16 6
COMAND Online see Multimedia sy stem
COMAND Touch
Managing devices.................................. 261
Combination switch .................................. 121
Compass................................................... .294
Compu ter
see On-board computer
Connection status
Displ aying.............................................. 325
Overview............................................... 325
Contacts Calling up.............................................. 304
Deleting................................................. 305
Downloading (from mobile phone)........ 303 Importing.............................................. 304
Importing (o
verview)............................. 304
Information........................................... .303
Making a call......................................... 305
Na me form at......................................... 304
Options................................................ .305
St oring..................................................3 05
Controller Operating.............................................. 24 9
Con venience closing ................................... 90
Con venience opening ..................................90
Coolant (engine) Check le vel............................................ 361
No tes..................................................... 424
Cooling see Climate control
Co pyright..................................................... 36
Cornering light ...........................................1 22
Cross Traf fic Alert..................................... .218
Crosswind Assist Function/no tes...................................... 171 Index
507

DIRECT SELECT le
ver
Engaging drive position........................ .152
Engaging neutral................................... .151
Engaging pa rkposition.......................... 15 2
Engaging pa rkposition automatically....1 52
Engaging reve rsege ar........................... .151
Fu nction................................................ 15 0
Display (care) ............................................ .369
Display (multimedia sy stem)
Settings................................................. 256
Display (on-boa rdcompu ter)
Displ ays on the multifunction displa y.... 229
Displ aymessage
Calling up (on-board compu ter)............ .430
No tes....................................................4 30
Display messages ¯ - - - km/h ..................................... 457
ç - - - km/h ..................................... 458
È - - - km/h ..................................... 457
# 12V battery See Owner's Man‐
ual......................................................... 472K
12V battery See Owner's Man‐
ual......................................................... 437
Û 48 V battery See Owner's Man‐
ual..........................................................4 74
: Active Light Sy stem inoperative... 439
¯ AdBlue sy stem fault Emer. op.:
max. XXX mphSt art not poss. in XXX
miles .................................................... .482
¯ AdBlue sy stem fault Emer‐
ge ncy op. in XXX km See Owner's
Manual.................................................. 481
¯ AdBlue sy stem fault Engine
st art not possible................................. .482
¯ AdBlue sy stem fault See Own‐
er's Manual ............................................ 481
5 Add 1 litre engine oil when
next refuelling....................................... 483
é ATTENTION ASSIST inoperative ....456
é ATTENTION ASSIS T:Take a
break!....................................................4 56:
Automatic driving lights inoper‐
ative...................................................... 438
Á Change key bat teries ...................4 34
J Checkbrake fluid le vel................. 455
5 Check engine oil le vel when
next refuelling....................................... 483
ï Checktrailer hitch lo ck................ 441
h Check tyre(s) ................................ 476
! Clean the fuel filter ...................... 448
J Close boot separator .................... 437
K Convertible Top Operation pos‐
sible to60 km/h................................... 436
ÿ Coolant Stop vehicle Switch
engine off..............................................4 46
! currently una vailable See Own‐
er's Manual ............................................ 467
÷ currently una vailable See Own‐
er's Manual .......................................... .468
5 Engine oil le vel cannot be
measured .............................................. 485 Index
509

App
lybrake todeselect Park (P)
position................................................. 449
App lybrake toselect R......................... 449
Au xilia rybattery malfunction (red
display message) ...................................4 51
Au xilia rybattery malfunction (white
display message) ...................................4 51
Beginning eme rgency stop.................... 460
Blind Spot Assist cur rently una vaila‐
ble See Owner's Manual ........................ 461
Blind Spot Assist inope rative ................. 462
Blind Spot Assi stnot available when
to wing a trailer See Owner's Manual .....4 62
Cannot start engine See Owner's
Manual................................................. .475
Check brake pads See Owner's Man‐
ual ........................................................ .455
Che cktyre pressu resth en restart
Ru n Flat Indicator................................. .479
Cruise control and Limi ter inoperative.. 457 Cruise control inoperative..................... 457
Cruise control off.................................. 457
Fr ont-passenger airbag disabled See
Owner's Manual....................................4 32
Fr ont-passenger airbag enabled See
Owner's Manual....................................4 32
Hazard warning lamps malfunctioning.. .441
Limiter inoperative................................ 457
Limiter passive ...................................... 457
Mercedes me connect Services limi‐
te d See Owner's Manual........................4 72
Mo tor can be star ted again.................... 475
N permanently active Risk of vehicle
ro lling .................................................... 449
Only select Park (P) when vehicle is
st ationary.............................................. 448
Pa rking Assist and PARKTRONIC
inoperative See Owner's Manual ...........466
Pa rking Assist Manoeuvring assis‐
ta nce limited See Owner's Manual........ 466 Place
theke y in the mar ked space
See Owner's Manual............................. 435
PRE-SAFE inoperative See Owner's
Manual..................................................4 33
Ra dar sensors dirty See Owner's
Manual................................................... 471
Re duce speed ........................................ 478
Re versing not poss. Consult work‐
shop......................................................4 50
Risk of vehicle rolling Driver door
open and transmission not in P............. 449
Ru n Flat Indicator inope rative............... .479
Speed limit (winter tyres) XXX km/h..... 459
St op vehicle Lea veengine running
Wa itTransmission cooling .....................450
To shift out of P or N,depress brake
and start engine.................................... 449
To switch off the engine, press
St art/ Stop button for at least 3 sec‐
onds or 3 times. ................................... .446 512
Index