2021 MERCEDES-BENZ C-CLASS CABRIOLET check engine

Checking
the coolant le vel &
WARNING Risk of bu rns from hot com‐
ponent parts in the engine compartment
Cer tain component parts in the engine com‐
partment can be very hot, e.g. the engine,
th e cooler and parts of theex haust sy stem. #
Allow the engine tocool down and only
to uch co mponent parts described in
th efo llowing. &
WARNING Risk of scalding from hot
coolant
If yo u open the cap, you could be scalded. #
Let the mo tor cool down before opening
th e cap. #
When opening the cap, wear pr otective
gl ove s and saf etygl asses. #
Open the cap slowly torelease pres‐
sure. #
Park theve hicle on a le vel sur face. #
Check the coolant temp erature display in the
instrument clus ter.
The coolant temp erature must be below
70°C. #
Slowly turn cap 1anti-clockwise torelease
ove rpressure. #
Continue turning cap 1anti-clockwise and
re mo veit.
The coolant le vel is cor rect in thefo llowing
cases:
R Ifth e engine is cold, the coolant is up to
mar ker bar 2.
R Ifth e engine is warm,th e coolant is up to
1. 5 cm overth e mar ker bar 2. #
If necessar y,top up with coolant that has
been appr ovedfo r Mercedes-Benz.
% Further information on coolant
(/ page 424) To
pping up the windsc reen washer sy stem &
WARNING Risk of bu rns from hot com‐
ponent parts in the engine compartment
Cer tain component parts in the engine com‐
partment can be very hot, e.g. the engine,
th e cooler and parts of theex haust sy stem. Maintenance and care
361

If
th e indicator/warning lamps in the instrument
clus ter do not light up at low temp eratures, it is
ve ry likely that the dischar ged battery has fro‐
zen. In this case you may neither jump-s tart the
ve hicle nor charge the batter y.
The service life of a battery that has been
th awe d may be dramatically shor tened. The
st arting characteristics may be impaired, espe‐
cially at low temp eratures.
It is recommended that you ha veathaw ed bat‐
te ry checked at a qualified specialist workshop.
All vehicles
* NO
TEDama gecaused bynumerous or
ex tended attem ptsto start the engine Nume
rous or extended attem ptsto start the
engine may damage the catalytic con verter
due tonon-combu sted fuel. #
Avoid numerous and extended attem pts
to start the engine. Obser
vethefo llowing points during starting
assis tance and when charging the battery:
R Only use undamaged jump lead/charging
cables with a suf ficient cross-section and
insula tedte rm inal clamps.
R Non- insulated parts of thete rm inal clamps
must not come into con tact wi thother me tal
parts while the jump lead/charging cable is
connected tothe battery/jump-s tart connec‐
tion point.
R The jump lead/charging cable must not
come into contact wi thany parts which may
mo vewhen the engine is running.
R Alw ays make sure that nei ther you nor the
battery is elect rostatically charge d.
R Keep away from fire and naked flames.
R Do not lean overth e batter y.
Obser vethe additional following points when
ch arging the battery:
R Only use battery charge rs tested and
appr oved for Mercedes-Benz.
R Read the battery charge r's operating instruc‐
tions before charging the batter y. Obser
vethe additional following points during
st arting assis tance:
R Starting assis tance may only be pr ovided
using vehicles, batteries or other jump start
devices with a nominal voltage of 12V.
R The vehicles must not touch.
R Vehicles with a petrol engine: jump-start
th eve hicle only when the engine and exhaust
sy stem are cold. St
arting assi stance and charging the12 V
battery Preparing
starting assi stance/charging #
Secure theve hicle byapplying the electric
parking brake. #
Automatic transmission: shiftthe trans‐
mission toposition j. #
Manual transmission: shiftthe transmis‐
sion toneutral. #
Switch off the ignition and all electrical con‐
sumers. #
Open the bonn et. 384
Breakdown assis tance

R
NOx exhaust gas af tertre atment malfunc‐
tions #
Avoid impurities in AdBlue ®
. Ad
Blue ®
re sidues cr ystallise af ter a period of
time, and contamina tethe sur faces wi thwhich
th ey come into contact. Clean the dirty sur faces
wi th wate r as soon as possible.
When you open theAd Blue ®
tan k,small
amounts of ammonia vapour may escape. Do
not inhale any ammonia vapours that may be
re leased. Only fill th eAd Blue ®
tank in well-venti‐
lated areas.
Ad Blue ®
filling capacity and consum ption Model
Total capacity
All models 14litres Ad
Blue ®
consu mption
The average AdBlue ®
consu mption is between
1% and 5% of fuel consumption. Li kefuel con‐
sum ption, AdBlue ®
consu mption is highly dependent upon driving
style and operating con‐
ditions. Forth is reason, your vehicle's actual
consum ption figures under da y-to -day operating
conditions may di ffer from the consum ption fig‐
ures calculated. The frequency at which you will
ha ve to to p up AdBlue ®
will also vary. Ha vethe
Ad Blue ®
supply checked at a qualified specialist
wo rkshop before making journe ysoutside of
Europe. Before a longer stay outside of Europe,
consult a qualified specialist workshop.
Ad Blue ®
ra nge and fill le vel
The AdBlue ®
fill le vel and range can be displ ayed
via the on-board computer. The AdBlue ®
ra nge
shown depends strongly on the driving style and
operating conditions. The actual range can
th erefore deviate from thera nge cur rently dis‐
pl ay ed in the on-board computer. The informa‐
tion supplied in the Owner's Manual rega rding
th ere ser vequantity at thefirs t display warning
and on the minimum top-up quantity when the
ta nk is em pty is also tobe under stood as guide
va lues. Engine oil
Note
s on engine oil
Obser vethe no tes on operating fluids
(/ page 416). *
NO
TEEngine dama gecaused byan
incor rect oil filter, incor rect oil or addi‐
tives #
Do not use engine oils or oil filters
which do not cor respond tothe specifi‐
cations explicitly prescribed forthe
service inter vals. 422
Tech nical da ta

Display messages
Possible causes/consequences and M
MSolutions
Hazard warning lamps mal-
functioning *T
he hazard warning lamp switch is malfunctioning. #
Consult a qualified specialist workshop. Ve
hicle Display messages
Possible causes/consequences and M MSolutions
d Vehicle is operational
Switch off ignition before
exiting *Y
ou are leaving theve hicle in a ready-to-drive state. #
When you lea vetheve hicle, switch off the ignition, secure theve hicle against rolling away and take theke y with
yo u. #
Ifyo u do not lea vetheve hicle, switch off the electrical consumers, e.g. the seat heating. Otherwise, the12 ‑V
battery may discharge and starting the engine may be possible only with the help of a second battery (jump
st art).
ï
Check trailer hitch lock *T
he trailer hitch is not operational during a journey with a trailer. &
WARNING Risk of an accident if the ball neck is not loc ked
The trailer may become de tach ed. #
Stop theve hicle immediately in accordance with the traf fic conditions. Do not continue driving. #
Uncouple the trailer and secure it against rolling away. #
Initiate a new swivel mo vement and do not re-couple the trailer until thewa rning/indicator lamp goes out. Display messages and
warning/indicator lamps 441

Engine
Display messages
Possible causes/consequences and M
MSolutions
To switch off the engine,
press Start/Stop button
for at least 3 seconds or 3
times. *Y
ou ha vepressed thest art/ stop button while theve hicle is in motion. #
Information about switching off the engine while driving (/ page138).
+ Top up coolant See Own-
er’s Manual *T
he coolant le vel is too lo w.
* NO
TEEngine dama gedue toinsuf ficient coolant #
Avoid long journe yswith insuf ficient coolant. #
Add coolant (/ page 361). #
Have the engine cooling sy stem checked at a qualified specialist workshop.
ÿ
Coolant Stop vehicle
Switch engine off *T
he coolant is too hot. #
Stop theve hicle immediately in accordance with the traf fic conditions and switch off the engine. 446
Displaymessa ges and warning/indicator lamps

Display messages
Possible causes/consequences and M
MSolutions
T
!
÷ inoperative See Owner's
Manual *
EBD, ABS and ESP ®
are malfunctioning.
Other driving sy stems and driving saf ety sy stems (e.g. BAS) may also be malfunctioning. &
WARNING Risk of skidding if EBD, ABS and ESP ®
are malfunctioning
The wheels may block du ring braking and ESP ®
does not pe rform any vehicle stabilization.
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. Active Brake Assist Func-
tions currently limited See
Owner's Manual *
Ve hicles with the Driving Assistance Package: Active Brake Assi stwith cross-traf fic function, Evasi veSteering
Assist or PRE‑SAFE ®
PLUS are temp orarily una vailable or only partially available.
Ve hicles without the Driving Assistance Package: Active Brake Assi stistemp orarily una vailable. #
Drive on.
As soon as the ambient conditions are within the sy stem limits, the sy stem will become available again. #
Ifth e display message does not disappear, stop theve hicle in accordance with the tra ffic conditions and restart
th e engine. 47 0
Displaymessa ges and warning/indicator lamps

Engine oil
Display messages
Possible causes/consequences and M
MSolutions
5 Check engine oil level
when next refuelling *T
he engine oil le vel has dropped tothe minimum le vel.
* NO
TEEngine dama gecaused bydriving with insuf ficient engine oil #
Avoid long journe yswith insuf ficient engine oil. #
Check the engine oil le vel when next refuelling.
To p up the engine oil (/ page 359).
No tes on engine oil (/ page 422).
5
Add 1 litre engine oil when
next refuelling *D
isplay message only for cer tain engines:
The engine oil le vel has dropped tothe minimum le vel.
* NO
TEEngine dama gecaused bydriving with insuf ficient engine oil #
Avoid long journe yswith insuf ficient engine oil. #
When next refuelling, add 1 litre of engine oil (/ page 359).
No tes on engine oil (/ page 422). Display messages and
warning/indicator lamps 483

Display messages
Possible causes/consequences and M
MSolutions
5 Engine oil level Reduce oil
level *D
isplay message only for cer tain engines:
The engine oil le vel is too high.
* NO
TEEngine dama gecaused bydriving with excess engine oil #
Avoid long journe yswith excess engine oil. #
Consult a qualified specialist workshop immediately and ha vethe engine oil le velre duced.
5 Engine oil level Stop vehi-
cle Switch engine off *D
isplay message only for cer tain engines:
The engine oil le vel is too lo w.
* NO
TEEngine dama gecaused bydriving with insuf ficient engine oil #
Avoid long journe yswith insuf ficient engine oil. #
Stop theve hicle immediately in accordance with the traf fic conditions. Do not continue driving. #
Switch off the engine. #
Add 1 l of engine oil (/ page 359). #
Check the engine oil le vel.
No tes on engine oil (/ page 422).484
Display messages and warning/indicator lamps