2021 MERCEDES-BENZ C-CLASS COUPE battery

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. 388
Breakdown assis tance

#
Fold co ver1 up in the direction of the
ar row. #
Slide co ver2 of positive clamp 3onthe
jump-s tarting connection point in the direc‐
tion of the ar row.
St arting assi stance #
Connect positive contact 3onyour vehicle
to the positive term inal of the donor battery
using the jump lead. Alw ays begin with posi‐
tive clamp 3onyour ow nve hicle firs t. #
Start the engine of the donor vehicle and run
it at idling speed. #
Connect the negative term inal of the donor
battery toear thpoint 4ofyour vehicle
using the jump lead. Begin with the donor
battery firs t. #
Start the engine of your ow nve hicle. #
Let the engines runfo r se veral minutes. #
Before disconnecting the jump leads, switch
on an electrical consumer in your ow nve hi‐
cle, e.g. there ar wind owheater or the light‐
ing.
When thest arting assis tance procedu reis com‐
ple te: #
First,re mo vethe jump leads from ear thpoint
4 and the negative term inal of the donor
batter y,then from positive conta ct3 and
th e positive term inal of the donor batter y.
Begin ea chtime wi th the conta cts onyour
ow nve hicle firs t. #
Afterre moving the jump leads, close co ver
2 of positive contact 3. #
Close co ver1. Breakdown assi
stance 389

Fu
rther information can be obtained at a quali‐
fi ed specialist workshop.
Charging #
Connect positive contact 3oftheve hicle to
th e positive term inal of thech arge r using the
ch arging cable. Alw ays begin with positive
contact 3oftheve hicle. #
Connect the negative term inal of thech arger
and ear thpoint 4ontheve hicle with the
ch arging cable. Start with thech arge r. #
Start thech arging process.
When thech arging process is comple te:#
First,re mo vethech arging cable from ear th
point 4and the negative term inal of the
ch arge r,th en from positive conta ct3 and
th e positive term inal of thech arge r.Begin
ea ch time wi th the conta cts oftheve hicle. #
Afterre moving thech arging cable, close
co ver2 of positive contact 3.#
Close co ver1.
Fu rther information can be obtained at a quali‐
fi ed specialist workshop. Re
placing the 12V battery #
Obser vethe no tes on the12 V battery
(/ page 385).
Mercedes-Benz recommends that you ha vethe
12 V battery replaced at a qualified specialist
wo rkshop, e.g. at a Mercedes-Benz Service
Centre.
Obser vethefo llowing no tes if youwa ntto
re place the battery yourself:
R Alw aysre place a faulty bat tery with a battery
which meets the specific vehicle require‐
ments.
The vehicle is equipped with an AGMtech nol‐
ogy battery (Absorbent Glass Mat) or a li th‐
ium-ion batter y.Fu llve hicle functionality is
only guaranteed with an AGM battery or lith‐
ium-ion batter y.Fo r saf etyre asons,
Mercedes-Benz recommends that you on ly
use bat teries which ha vebeen tested and
appr ovedfo ryo ur vehicle byMercedes-Benz.
R Carryove r de tach able parts, such as vent
hoses, elbow fittings or term inal co vers from
th e battery being replaced. R
Make sure that theve nt hose is al ways con‐
nected tothe original opening on the side of
th e batter y.
Fit any existing or supplied cell caps.
Otherwise, gases or battery acid could
escape.
R Make sure that de tach able parts are recon‐
nected in the same way. To
w- starting or towing away Pe
rm itted towing me thods *
NO
TEDama gefrom auto matic braking If one of
thefo llowing functions is switched
on, theve hicle brakes automatically in cer‐
ta in situations:
R Active Brake Assi st
R Active Dis tance Assi stDISTRONIC
R HOLD function
R Active Parking Assist 390
Breakdown assis tance

To
avo id damage totheve hicle, deactivate
th ese sy stems in thefo llowing or similar sit‐
uations: #
During towing #
In a car wash Mercedes-Benz
recommends transporting your
ve hicle in the case of a breakdown, rath er than
to wing it away.
Fo rto wing, use a tow rope or tow bar with bo th
axles on the ground. Do not use tow bar sys‐
te ms.
* NO
TEDama getotheve hicle due to tow‐
ing away incor rectly #
Obser vethe instructions and no tes on
to wing away. Ve
hicles with manual transmission Pe
rm itted towing me thods
Bo th axles on
th e ground Ye
s, maximum 50 km at
50 km/h
Fr ont axle
ra ised Ye
s, maximum 50 km at
50 km/h
Re ar axle
ra ised Ye
s, maximum 50 km at
50 km/h Ve
hicles with automatic transmission Pe
rm itted towing me thods
Bo th axles on
th e ground Ye
s, maximum 50 km at
50 km/h
Fr ont axle
ra ised No
Re ar axle
ra ised Ye
s, if thesteering wheel is
fi xe d in the cent reposition
with a steering wheel lock 4MATIC
vehicles Pe
rm itted towing me thods
Bo th axles on
th e ground Ye
s, maximum 50 km at
50 km/h
Fr ont axle
ra ised No
Re ar axle
ra ised No To
wing with a raised axle: towing should be
per form ed byato wing compan y. To
wing theve hicle with bo thaxles on the
gr ound #
Obser vethe no tes on the permitted towing
me thods (/ page 390). #
Make sure that the battery is connected and
ch arge d.
Obser vethefo llowing points when the battery is
dischar ged:
R the engine cann otbe star ted Breakdown assis
tance 391

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

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. Climate control
Display messages
Possible causes/consequences and M MSolutions
& inoperative See Owner's
Man. *T
hestationary heater is temp orarily malfunctioning. #
When theve hicle is stationary on a le vel sur face and the engine has cooled down, make up tofour attem ptsto
switch on thest ationary heater, waiting se veral minutes between each attem pt. #
Ifth est ationary heater does not swit chon, consult a qualified specialist workshop.
&
inoperative Battery low *T
he on-board electrical sy stem voltage is too lo w.
The stationary heater has swit ched itself off. #
Drive an extended di stance until the battery has reached a suf ficient charge leve l again.
&
inoperative Refuel vehicle *T
here is too little fuel in the fuel tank. The stationary heater cannot be swit ched on. #
Refuel theve hicle. 442
Displaymessa ges and warning/indicator lamps

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. #
Initiate a new swivel mo vement (/ page 227). #
When the display message disappears, couple up the trailer and drive on.
If th e display message does not disappear, the trailer hitch is malfunctioning and the ball neck is not loc ked. Display messages and
warning/indicator lamps 443

Display messages
Possible causes/consequences and M
MSolutions #
Consult a qualified specialist workshop.
Stop vehicle Leave engine
running Wait Transmission
cooling *T
he transmission is overheating. Pulling away may be temp orarily impaired or not possible. #
Stop theve hicle immediately in accordance with the traf fic conditions. Do not continue driving. #
Lea vethe engine running. #
Wait until the display message disappears before pulling away.
Auxiliary battery malfunc-
tion (whitedisplay mes‐
sage) *T
he auxiliary batteryforth e transmission is no longer being charge d. #
Consult a qualified specialist workshop. #
Untilthen, alw ays select park position jmanually before you swit choff the engine. #
Before leaving theve hicle, apply the electric parking brake.
Auxiliary battery malfunc-
tion (red display message) *T
he auxiliary batteryforth e transmission is no longer being charge d. #
Consult a qualified specialist workshop. #
Untilthen, alw ays select park position jmanually before you swit choff the engine. #
Before leaving theve hicle, apply the electric parking brake. 452
Display messages and warning/indicator lamps