change key battery MERCEDES-BENZ C-CLASS COUPE 2021 Owners Manual

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
Display messages
Possible causes/consequences and M
MSolutions
Á Replace key *H
avetheke yre placed. #
Consult a qualified specialist workshop.
Á Change key batteries *T
hekey bat tery is dischar ged. #
Replace the battery (/ page73).
Á
Key not detected (white dis‐
play message) *T
hekey is cur rently und etected. #
Change the location of theke y in theve hicle. #
Ifth eke y is still not recognised, place it in the slot forst arting with theke y (/ page146). Displ
aymessa ges and warning/indicator lamps 437

DIRECT SELECT le
ver
Engaging drive position........................ .159
Engaging neutral................................... .158
Engaging park position.......................... 15 9
Engaging pa rkposition automatically....1 59
Engaging reve rsege ar........................... 15 8
Fu nction................................................ 157
Display (care) ............................................ .374
Display (multimedia sy stem)
Settings................................................. 263
Display (on-boa rdcompu ter)
Displ ays on the multifunction displa y.... 236
Displ aymessage
Calling up (on-board compu ter)............. 433
No tes....................................................4 33
Display messages ¯ - - - km/h ..................................... 458
ç - - - km/h ..................................... 459
È - - - km/h ..................................... 459
# 12V battery See Owner's Man‐
ual..........................................................4 74Û
48 V battery See Owner's Man‐
ual.......................................................... 476
: Active Light Sy stem inoperative... 440
¯ AdBlue sy stem fault Emer. op.:
max. XXX mphSt art not poss. in XXX
miles .................................................... .484
¯ AdBlue sy stem fault Emer‐
ge ncy op. in XXX km See Owner's
Manual.................................................. 483
¯ AdBlue sy stem fault Engine
st art not possible................................. .484
¯ AdBlue sy stem fault See Own‐
er's Manual .......................................... .483
5 Add 1 litre engine oil when
next refuelling....................................... 485
é ATTENTION ASSIST inoperative ....458
é ATTENTION ASSIS T:Take a
break!....................................................4 58
: Automatic driving lights inoper‐
ative...................................................... 439 Á
Change key bat teries .................... 437
J Check brake fluid le vel................. 456
# Check brake pads See Owner's
Manual.................................................. 457
5 Check engine oil le vel when
next refuelling....................................... 485
ï Checktrailer hitch lo ck................ 443
h Check tyre(s) ................................ 478
! Clean the fuel filter ...................... 449
ÿ Coolant Stop vehicle Switch
engine off..............................................4 48
! currently una vailable See Own‐
er's Manual .......................................... .469
÷ currently una vailable See Own‐
er's Manual .......................................... .470
5 Engine oil le vel cannot be
measured .............................................. 487
5 Engine oil le velRe duce oil le vel.... 486
5 Engine oil le velSt op vehicle
Switch engine off.................................. 486 Index
511