2021 MERCEDES-BENZ C-CLASS CABRIOLET key battery

tion, number of wheel
revo lutions or thefa s‐
te ned seat belts displ ay
R ambient conditions, such as temp erature,
ra in sensor or dis tance sensor
General ly,th e use of these data is temp orar y;
th ey will not be stored be yond the period of
operation and will only be processed within the
ve hicle itself. Control units of ten contain da ta
memories forve hicle keys,fo rex ample. Their
use permits thete mp orary or permanent docu‐
mentation of tech nical information about the
ve hicle's operating state, component loads,
main tenance requ irements and tech nical events
or faults.
Depending on theve hicle equipment, thefo llow‐
ing data are stored:
R operating status of sy stem components,
such as fill le vels, tyre pressure or battery
st atus
R malfunctions or faults in impor tant sy stem
components, such as lights or brakes
R system reactions in special driving situations,
such as airbag deployment or the inter ven‐
tion of stability control sy stems R
information on events leading tovehicle
damage
In cer tain cases, it may be requiredtostore data
th at wo uld ha veotherwise been used only tem‐
poraril y.This may be the case if theve hicle has
de tected a malfunction, forex ample.
If yo u use services, such as repair services and
maintenance work,st ored operational data as
we ll as theve hicle identification number can be
re ad out and used. They can be read out by
service network emplo yees, such as workshops
and manufacturers or third parties, such as
breakdown services. The same is true in the
case of warranty claims and quality assurance
measures.
In general, there adout is per form ed via the
legally prescribed port forth e diagnostics con‐
nection in theve hicle. The operational data that
are read out document tech nical states of the
ve hicle or of individual components and assist in
th e diagnosis of malfunctions, compliance with
wa rranty obligations and quality impr ovement.
To that end, these data, in particular information
about component loads, tech nical events, mal‐ functions and
other faults may be transmitted
along with theve hicle identification number to
th e manufacturer. Furthermore, the manufac‐
turer is subject toproduct liability. Forth is rea‐
son the manufacturer also uses operational data
from theve hicle, forex ample, forre calls. These
da ta can also be used toexamine the cus tom‐
er's warranty and guarantee claims.
Fa ult memories in theve hicle can be reset by a
service outlet or at your requ est as part of repair
or maintenance work.
Con venience and inf otainment functions
Yo u can store con venience settings and individ‐
ual settings in theve hicle and change or reset
th em at any time.
Depending on theve hicle equipment, this
includes thefo llowing settings, forex ample:
R seat and steering wheel positions
R suspension and climate control settings
R individual settings, such as interior lighting
Depending on the selected equipment, you can
import data into vehicle inf otainment functions
yo urself. 34
General no tes

Key
Overview of
the function &
WARNING Risk of accident and inju ry
due toleaving children unat tended in the
ve hicle
If ch ildren are left unat tended in theve hicle,
th ey could, in pa rticular:
R open doors, thereby endangering other
persons or road users.
R get out and be stru ck byoncoming traf‐
fi c.
R ope rate ve hicle equipment and become
trapped, forex ample.
In addition, thech ildren could also set the
ve hicle in motion by,fo rex ample:
R releasing the parking brake.
R changing the transmission position.
R starting theve hicle. #
Never lea vechildren unat tended in the
ve hicle. #
When leaving theve hicle, alw aysta ke
th eke y with you and lock theve hicle. #
Keep theve hicle key out of there ach of
ch ildren. *
NO
TEDama getotheke y caused by
magnetic fields #
Keep theke yaw ay from strong mag‐
netic fields. Ve
hicle key
1 Locks
2 Indicator lamp 3
Unloc ks
4 Opens the boot lid
% If indicator lamp 2does not light up af ter
pressing theÜ orß button, the bat‐
te ry iswe ak or possibly dischar ged. Re place
th e battery as soon as possible.
Re place theke y bat tery ( / page 74).
The key loc ksand unlo cksth efo llowing compo‐
nents:
R doors
R fuel filler flap
R boot lid
If th eve hicle is not opened within appr oximately
40 seconds af ter unlocking, it loc ksagain. Anti-
th eft pr otection is primed again.
Do not keep theke yto get her with electronic
devices or me tal objects. This can af fect the
ke y's functionalit y.72
Opening and closing

Re
moving/inserting the eme rgency key Re
moving the eme rgency key #
Press release button 1.
Emer gency key2 is pushed out slight ly.#
Pull out emer gency key2 until it en gage s in
th e intermediate position. #
Press release button 1again and fully
re mo veemer gency key2.
Inserting the emer gency key #
Press release button 1. #
Insert emer gency key2 tothe intermediate
position or fully until it engages. %
You can use the intermediate position of
emer gency key2 toattach theke yto akey
ri ng. Re
placing the key battery &
DANG ER Risk of fata l injuries due to
swallowing batteries
Batteries contain toxic and cor rosive sub‐
st ances. Swallowing bat teries may cause
se vere internal burns tooccur within two
hours.
There is a risk of fata l injur y. #
Keep batteries out of there ach of chil‐
dren. #
Ifth e cap and/or the battery compart‐
ment does not close securel y,do not
use theke y any lon ger and keep it out
of there ach of children. #
If batteries are swallo wed, seek medical
attention immediately. +
ENVIRONMEN
TALNO TEEnvironmental
dama gedue toimproper disposal of bat‐
te ries Batteries conta
in pollutants. It is
illegal todispose of them with the household
ru bbish. #
Dispose of batteries in an
environmen tally responsible manner.
Ta ke dischar ged batteries toaqu alified
specialist workshop or toa collection
point for used batteries. Re
quirements:
R Yourequ ire a CR 2032 3 V cell batter y.
Mercedes-Benz recommends that you ha vethe
battery replaced at a qualified specialist work‐
shop. 74
Opening and closing

#
Remo vethe emer gency key ( / page 74). #
Press release knob 2down fully and slide
co ver1 inthe direction of the ar row. #
Fold out co ver1 inthe direction of the
ar row and remo ve. #
Remo vebattery compartment 3and take
out the dischar ged batter y. #
Insert the new battery into battery compart‐
ment 3. Obser vethe positive pole marking
in the battery compartment and on the bat‐
te ry when doing this. #
Push in battery compartment 3. #
Re-attach co ver1 and push it until it
engages. Problems with
theke y,troublesho oting Yo
u can no lon ger lo ckor unlock theve hicle
Po ssible causes:
R The key bat tery iswe ak or dischar ged. #
Check the battery using the indicator lamp
(/ page 72). #
Replace theke y bat tery, if necessary
(/ page 74). #
Use there placement key. #
Use the emer gency keyto lock or unlock
(/ page 79). #
Have theke ych ecked at a qualified specialist
wo rkshop.
There is inter fere nce from a po werful radio
signal source
Po ssible causes if the function of theke y is
impaired:
R high voltage po wer lines R
mobile phones
R electronic devices (no tebooks, tablets)
R shielding due tome tal objects or induction
loops for electrical gatesystems or auto‐
matic bar riers #
Make sure that there is suf ficient di stance
between theke y and the po tential sou rce of
inter fere nce.
Yo u ha velost a key #
Have theke y deacti vated at a qualified spe‐
cialist workshop. #
If necessar y,ha ve the mechanical lock
re placed as well. Doors
Note
s onthe additional door lock The additional door lock is only
available for
ve hicles forth eUni ted Kingdom. Opening and closing
75

If
yo u open the boot lid from outside, the boot lid
is automatically unloc ked. Problems with KEYLESS-GO, troubleshooting
Yo
u can no lon ger lo ckor unlock theve hicle
using KEYLESS-GO
Po ssible causes:
R The function of theke y has been deacti vated.
R The key bat tery iswe ak or dischar ged. #
Activate the function of theke y ( / page 73). #
Check the battery using the indicator lamp
(/ page 72). #
Replace theke y bat tery, if necessary
(/ page 74). #
Use there placement key. #
Use the emer gency keyto lock or unlock
(/ page 79). #
Have theve hicle and keych ecked at a quali‐
fi ed specialist workshop. There is inter
fere nce from a po werful radio
signal source
Po ssible causes if the function of KEYLESS-GO is
impaired:
R high voltage po wer lines
R mobile phones
R electronic devices (no tebooks, tablets)
R shielding due tome tal objects or induction
loops for electrical gatesystems or auto‐
matic bar riers #
Make sure that there is suf ficient di stance
between theke y and the po tential sou rce of
inter fere nce. Ac
tivating/deactivating the automatic lo ck‐
ing feature The
vehicle is loc ked automatically when the
ignition is switched on and the wheels are turn‐
ing fast erthan walking pace. #
Toactivate: press and hold button 2for
appr oximately five seconds until an acoustic
signal sounds. #
Todeactivate: press and hold button 1for
appr oximately five seconds until an acoustic
signal sounds. 78
Opening and closing

#
Check the battery using the indicator lamp
(/ page 72). #
Replace theke y bat tery, if necessary
(/ page 74). Anti-theft pr
otection Fu
nction of the immobiliser The immobiliser pr
events your vehicle from
being star ted without the cor rect key.
The immobiliser is automatically activated when
th e ignition is switched off and deactivated when
th e ignition is switched on. ATA
(Anti-Theft Alarm sy stem) Fu
nction of theATA system
If th eATA system is primed, a visual and audible
alarm is triggered in thefo llowing situations:
R when a door is opened
R when the boot lid is opened
R when the bonn etis opened R
when interior pr otection is triggered
(/ page 93)
R when tow- aw ay protection is triggered
(/ page 93)
The ATA system is primed automatically af ter
appr oximately ten seconds in thefo llowing situa‐
tions:
R afte r locking theve hicle with thekey
R afte r locking theve hicle using KEYLESS-GO Indicator lamp
1flashes when theAT A sy stem
is primed.
The ATA sy stem is deactivated automatically in
th efo llowing situations:
R afte r unlocking theve hicle with thekey
R afte r unlocking theve hicle using KEYLESS-
GO 92
Opening and closing

St
arting theve hicle with theke y in the
ma rked space (emer gency operation mode)
If th eve hicle does not start and thePlace the
key in the marked space See Owner's Manual
message appears in the multifunction displa y,
yo u can start theve hicle in emer gency operation
mode. #
Makesure that the mar ked space 2is
em pty. #
Remo vetheke y1 from theke yring. #
Place theke y1 inthe mar ked space 2on
th e symbol 3.
The vehicle will start af ter a short time.
If yo ure mo vetheke y1 from the mar ked
space 2,the engine continues running. For
fur ther engine starts ho wever,th eke y1
must be located in the mar ked space 2on
th e symbol 3during the entire journe y. #
Have theke y1 checked at a qualified spe‐
cialist workshop.
If th eve hicle does not star t: #
place theke y1 inthe mar ked space 2
and lea veitth ere. #
Depress the brake pedal and start theve hi‐
cle using thest art/ stop button.
% You can also swit chon the po wer supp lyor
th e ignition with thest art/ stop button.
Obser veany information rega rding display mes‐
sages that can be displa yed on the multifunction
displa y. St
arting theve hicle via Remo teOnline Serv‐
ices Cooling or heating
theve hicle interior before
st arting the jou rney
Ensu rethefo llowing before starting the engine:
R the legal stipulations in the area where your
ve hicle is par ked allow engine starting via
smartphone.
R it is safe tostart and runth e engine where
yo ur vehicle is par ked.
R the fuel tank is su fficiently full.
R thest ar ter battery is suf ficiently charge d.
Charging thest ar ter battery be fore starting
th e jou rney
If th eve hicle battery is dischar ged, you can
re cei vea message on your smartphone. You can
th en start theve hicle with the smartphone to
ch arge the batter y.The vehicle is automatically
switched off af terte n minu tes. Driving and parking
13 9

Sy
stem limits
De tection may be restricted in thefo llowing sit‐
uations:
R theve hicle is damaged without impact, e.g. if
an outside mir ror is torn off or the paint is
damaged byakey
R an impact occurs at low speed
R the electric parking brake is not applied Note
s on parking up theve hicle If
yo u lea vetheve hicle par ked up for longer than
six weeks, it may suf fer dama gethro ugh disuse.
The 12V battery may also be impaired or dam‐
aged byheavy discharging.
% Further information can be obtained at a
qu alified specialist workshop. St
andby mode (extension of the star ter bat‐
te ry 's period out of use) St
andby mode function
% This function is not available for all models. If
standby mode is activated, ene rgy loss will be
minimised during extended pe riods of non-oper‐
ation.
St andby mode is characterised bythefo llowing:
R The star ter battery is preser ved.
R The maximum non-operational time appears
inthe media displa y.
R The connection toonline services is inter rup‐
te d.
R The ATA (anti-theft alarm sy stem) is una vaila‐
ble.
R The interior pr otection and tow- aw ay protec‐
tion functions are not available.
R The function for de tecting collisions on a
pa rked vehicle is not available.
If th efo llowing conditions are fulfilled, standby
mode can be activated or deactivated using the
multimedia sy stem:
R The engine is switched off.
R The ignition is switched on.
Exceeding theve hicle's displa yed non-opera‐
tional time may cause incon venience, i.e. it can‐ not be guaranteed
that thest ar ter battery will
re liably start the engine.
The star ter battery must be charge dfirs t in the
fo llowing situations:
R The vehicle's non-operational time must be
ex tended.
R The Battery charge insufficient for standby
mode messa geappears in the media displa y.
% Standby mode is automatically deactivated
when the ignition is switched on.
Ac tivating/deactivating standby mode
Multimedia sy stem:
4 Vehicle 5
î Vehicle settings
5 Standby mode
% This function is not available for all models. #
Activate Oor deacti vate ª the function.
When you activate the function, a prom pt
appears. #
Select Yes.
St andby mode is activated. Driving and parking
167