2018 MERCEDES-BENZ C-CLASS SEDAN key battery

Problems with the engine
ProblemPossible causes/consequences andMSolutions
The engine does not
start.The HOLD function or Distance Pilot DISTRONIC is activated.
XDeactivate the HOLD function (Ypage 180) or Distance Pilot
DISTRONIC (Ypage 176).
XTry to start the engine again (Ypage 138).
The engine does not
start. The starter motor
can be heard.RThere is a malfunction in the engine electronics.
RThere is a malfunction in the fuel supply.
Before attempting to start the engine again:
XTurn the SmartKey back to position uin the ignition lock.
or
XPress the Start/Stop button repeatedly until all indicator lamps in
the instrument cluster go out.
XTry to start the engine again (Ypage 138). Avoid excessively long
and frequent attempts to start the engine as these will drain the
battery.
If the engine does not start after several attempts:
XConsult a qualified specialist workshop.
The engine does not
start. The starter motor
can be heard. The
reserve fuel warning
lamp is lit and the fuel
gauge display is at the
reserve level.The fuel tank is empty.
XRefuel the vehicle.
The engine does not
start. You cannot hear
the starter motor.The on-board voltage is too low because the battery is too weak or
discharged.
XJump-start the vehicle (Ypage 325).
If the engine does not start despite attempts to jump-start it:
XConsult a qualified specialist workshop.
The starter motor was exposed to a thermal load that was too high.
XTry to start the engine again (Ypage 138).
If the engine still does not start:
XConsult a qualified specialist workshop.
Driving143
Driving and parking
Z

Problems with fuel and the fuel tank
ProblemPossible causes/consequences andMSolutions
Fuel is leaking from the
vehicle.GWARNING
The fuel line or the fuel tank is faulty.
Risk of explosion or fire.
XApply the electric parking brake.
XSwitch off the engine.
XRemove the SmartKey from the ignition lock.
or, in vehicles with KEYLESS-GO start-function or KEYLESS ‑GO
XOpen the driver's door.
The vehicle electronics are now in positionu. This is the same as
the key having been removed.
XDo not restart the engine under any circumstances.
XConsult a qualified specialist workshop.
The engine does not
start.The fuel tank of a vehicle with a diesel engine has been run completely
dry.
XRefuel the vehicle with at least 5.3 US qt (5 l) of diesel.
XTurn the ignition on for approximately ten seconds (Ypage 136).
XStart the engine continuously for up to ten seconds until it runs
smoothly.
If the engine does not start:
XTurn the ignition on again for approximately ten seconds
(Ypage 136).
XStart the engine again continuously for up to ten seconds until it
runs smoothly.
If the engine does not start after three attempts:
XConsult a qualified specialist workshop.
The fuel filler flap cannot
be opened.The fuel filler flap is not unlocked.
XUnlock the vehicle (Ypage 78).
The SmartKey battery is discharged or nearly discharged.
XUnlock the vehicle using the mechanical key (Ypage 80).
The fuel filler flap is unlocked, but the opening mechanism is jammed.
XConsult a qualified specialist workshop.
DEF (BlueTEC vehicles only)
General notes
To function properly, BlueTEC exhaust gas after-
treatment must be operated with the reducing
agent DEF. On vehicles with a 2.4 gal (9.0
l)DEF tank, add-
ing DEF is not part of the maintenance work.
When the DEF supply drops to a minimum, the
Check Additive See Owner's Manualmes-
sage is shown in the multifunction display.
If you drive the vehicle at a speed greater than
10 mph (16 km/h) after topping up, the Check
158Refueling
Driving and parking

Display messagesPossible causes/consequences andMSolutions
Ð
Power Steering Mal‐function See Opera‐tor's Manual
The powersteering is malfunctioning .
A warning tone also sounds.
GWARNIN G
You will need to use mor eforce to steer .
There is aris kof an accident.
XChec kwhether you are able to apply th eextr aforce required.
If you ar eabl eto steer safely:
XDrive on carefully.
XVisit aqualified specialist workshop immediately.
If you ar eunable to steer safely:
XDo no tdrive on .
XConsult aqualified specialist workshop .
Phone No ServiceYour vehicleis outside th enetwork provider' stransmitter/receiver
range.
XWait until th emobile phone operational readiness symbol appear s
in th emultifunction display.
¥
Check Washer Fluid
The washer flui dlevel in th ewasher flui dreservoir has dropped belo w
th eminimum .
XAddwasher flui d (Ypage 307).
SmartKey
Display messagesPossible causes/consequences and MSolutions
Â
KeyDoesNotBelongto Vehicl e
You haveput th ewrong SmartKey in th eignition lock.
XUse th ecorrec tSmartKey.
Â
Tak eYou rKey fro mIgnition
The SmartKey is in th eignition lock.
A warning tone sounds
XRemove th eSmartKey.
Â
Obtain aNew Key
The SmartKey needs to be replaced.
XVisit aqualified specialist workshop .
Â
ReplaceKey Batter y
The SmartKey battery is discharged.
XChange thebatterie s (Ypage 81) .
Display messages257
On-board computer and displays
Z

Cigarette lighter
GWARNING
You can burn yourself if you touch the hot
heating element or the socket of the cigarette lighter.
In addition, flammable materials can ignite if:
Rthe hot cigarette lighter falls
Ra child holds the hot cigarette lighter to
objects, for example
There is a risk of fire and injury.
Always hold the cigarette lighter by the knob.
Always make sure that the cigarette lighter is
out of reach of children. Never leave children
unsupervised in the vehicle.
Your attention must always be focused on the
traffic conditions. Only use the cigarette lighter when road and traffic conditions permit.
Cigarette lighter (example)
XTurn the SmartKey to position 2in the igni-
tion lock (Ypage 136).
XTo open: open the stowage compartment
(Ypage 281).
XPress in cigarette lighter ;.
Cigarette lighter ;will pop out automatically
when the heating element is red-hot.
XTo close: push cover :of the stowage com-
partment closed.
12 V sockets
General notes
XTurn the SmartKey to position 1in the igni-
tion lock (Ypage 136). The sockets can be used for accessories with a
maximum draw of 180 W (15 A). Accessories
include such items as chargers for mobile
phones.
If you use the sockets for long periods when the
engine is switched off, the battery may dis-
charge.
An emergency cut-out ensures that the on-
board voltage does not drop too low. If the on-
board voltage is too low, the power to the sock-
ets is automatically cut. This ensures that there
is sufficient power to start the engine.
If you have connected a device to the 12 V
socket, leave the cover of the stowage com-
partment open. This prevents the cover from
being blocked.
Socket in the front center console
12 V socket (example)
XTo open:
open the stowage compartment
(Ypage 281).
XLift up the cover of socket ;.
XTo close:push cover :of the stowage com-
partment closed.
Socket in the rear compartment center
console
292Features
Stowage and features

XDo not point the water jet directly towards the
air inlet.
XUse plenty of water and rinse out the sponge
frequently.
XRinse the vehicle with clean water and dry
thoroughly with a chamois.
XDo not let the cleaning agent dry on the paint-work.
Carefully remove all deposits of road salt as
soon as possible when driving in winter.
Power washers
GWARNING
The water jet from a circular jet nozzle (dirt
blasters) can cause invisible exterior damage
to the tires or chassis components. Compo-
nents damaged in this way may fail unexpect-
edly. There is a risk of an accident.
Do not use power washers with circular jet
nozzles to clean the vehicle. Have damaged
tires or chassis components replaced imme-
diately.
!Always maintain a distance of at least
11.8 in (30 cm) between the vehicle and the
power washer nozzle. Information about the
correct distance is available from the equip-
ment manufacturer.
Move the power washer nozzle around when
cleaning your vehicle.
Do not aim directly at any of the following:
RTires
RDoor gaps, roof gaps, joints, etc.
RElectrical components
RBattery
RConnectors
RLamps
RSeals
RTrim
RVentilation slots
Damaged seals or electrical components can
lead to leaks or failures.
!Vehicles with decorative film: parts of your
vehicle are covered with a decorative film.
Maintain a distance of at least 27.5 in (70 cm)
between the parts of the vehicle covered with
the film and the nozzle of the high pressure
cleaner. Information about the correct distance
is
a

vailable from the equipment manufacturer.
Move the power washer nozzle around when
cleaning your vehicle.
!If the SmartKey is within the rear detection
range of KEYLESS-GO, the following situa-
tions, for example, could lead to the uninten-
tional opening of the trunk:
Rusing a car wash
Rusing a power washer
Make sure that the SmartKey is at least 10 ft
(3 m) away from the vehicle.
Cleaning the paintwork
!Do not affix:
Rstickers
Rfilms
Rmagnetic plates or similar items
to painted surfaces. You could otherwise
damage the paintwork.
Scratches, corrosive deposits, areas affected by
corrosion and damage caused by inadequate
care cannot always be completely repaired. In
such cases, visit a qualified specialist workshop.
XRemove dirt immediately, where possible,
while avoiding rubbing too hard.
XSoak insect remains with insect remover and
rinse off the treated areas afterwards.
XSoak bird droppings with water and rinse off
the treated areas afterwards.
XRemove coolant, brake fluid, tree resin, oils,
fuels and greases by rubbing gently with a
cloth soaked in petroleum ether or lighter
fluid.
XUse tar remover to remove tar stains.
XUse silicone remover to remove wax.
If water no longer forms "beads" on the paint
surface, use the paint care products recommen-
ded and approved by Mercedes-Benz. This is the
case approximately every three to five months,
depending on the climate conditions and the
care product used.
The cleaning product Paint Cleaner, which has
been recommended and approved by
Mercedes-Benz, shoul d b
e used when dirt has
penetrated the paint surface.
Also use Paint Cleaner on paint that has become
dull.
310Care
Maintenance and care

Electrolyte or battery acid is corro-
sive. Avoid contact with skin, eyes or
clothing.
Wear suitable protective clothing,
especially gloves, apron and face-
guard.
Immediately rinse electrolyte or acid
splashes off with clean water. Con-
tact a physician if necessary.
Wear eye protection.
Keep children away.
Observe this Operator's Manual.
For safety reasons, Mercedes-Benz recom-
mends that you only use batteries which have
been tested and approved for your vehicle by
Mercedes-Benz. These batteries provide
increased impact protection to prevent vehicle
occupants from suffering acid burns should the
battery be damaged in the event of an accident.
In order for the battery to achieve the maximum
possible service life, it must always be suffi-
ciently charged.
Like other batteries, the vehicle battery may
discharge over time if you do not use the vehicle.
In this case, have the battery disconnected at a
qualified specialist workshop. You can also
charge the battery with a charger recommended
by Mercedes-Benz. Contact a qualified special-
ist workshop for further information.
Have the battery condition of charge checked
more frequently if you use the vehicle mainly for
short trips or if you leave it standing idle for a
lengthy period. Consult a qualified specialist
workshop if you wish to leave your vehicle
parked for a long period of time.
Remove the SmartKey if you park the vehicle
and do not require any electrical consumers.
The vehicle will the n u
se very little energy, thus
conserving battery power.
Charging the 12 V battery
Vehicles with a lithium-ion battery:
!Only use battery chargers with a maximum
charging voltage of 14.4 V.
Al lve hicles except vehicles with a lithium-
ion battery:
!Only use battery chargers with a maximum
charging voltage of 14.8 V.
GWARNING
During charging and jump-starting, explosive
gases can escape from the battery. There is a risk of an explosion.
Particularly avoid fire, open flames, creating
sparks and smoking. Ensure there is sufficient
ventilation while charging and jump-starting.
Do not lean over a battery.
GWARNING
Battery acid is caustic. There is a risk of injury.
Avoid contact with skin, eyes or clothing. Do
not inhale any battery gases. Do not lean over
the battery. Keep children away from batter-
ies. Wash away battery acid immediately with
plenty of clean water and seek medical atten-
tion.
GWARNING
A discharged battery can freeze at tempera-
tures below freezing point. When jump-start-
ing the vehicle or charging the battery, gases can escape from the battery. There is a risk of
an explosion.
Allow the frozen battery to thaw out before
charging it or jump-starting.
All vehicles:
!Only charge the battery using the jump-
starting connection point.
The jump-starting connection point is in the
engine compartment (
Ypage 325).
XOpen the hood.
XConnect the battery charger to the positive
terminal and ground point in the same order
as when connecting the donor battery in the
jump-starting procedure (
Ypage 325).
Keep away from fire and open flames. Do not
lean over a battery. Never charge the battery if it
is still installed in the vehicle, unless you use a
324Battery (vehicle)
Breakdown assistance

GWARNING
A discharged battery can freeze at temperatures below freezing point. When jump-starting the
vehicle or charging the battery, gases can escape from the battery. There is a risk of an explosion. Allow the frozen battery to thaw out before charging it or jump-starting.
If the warning and indicator lamps do not light up on the instrument cluster when temperatures are low, it is probably because the discharged battery has frozen. In this case, you may neither charge
the battery nor jump-start the vehicle. The service life of a thawed-out battery may be shorter. The
starting characteristics can be impaired, particularly at low temperatures. Have the thawed-out
battery checked at a qualified specialist workshop.
All vehicles:
!Vehicles with a gasoline engine: avoid repeated and lengthy starting attempts. Otherwise, the
catalytic converter could be damaged by non-combusted fuel.
Do not start the vehicle using a rapid charging device. If your vehicle's battery is discharged, the
engine can be jump-started from another vehicle or from a second battery using jumper cables.
Observe the following points:
RThe battery is not accessible in all vehicles. If the other vehicle's battery is not accessible, jump-
start the vehicle using a second battery or a jump-starting device.
RVehicles with a gasoline engine: only jump-start the vehicle when the engine and exhaust
system are cold.
RAll vehicles except vehicles with a lithium-ion battery: do not start the engine if the battery
is frozen. Let the battery thaw first.
RJump-starting may be performed only using batteries with a nominal voltage of 12 V.
ROnly use jumper cables which have a sufficient cross-section and insulated terminal clamps.
RIf the battery is fully discharged, leave the battery that is being used to jump-start connected for
a few minutes before attempting to start. This charges the battery slightly.
RMake sure that the two vehicles do not touch.
Make sure that:
RThe jumper cables are not damaged.
RBare parts of the terminal clamp do not come into contact with other metal parts while the jumper
cables are connected to the battery.
RThe jumper cables cannot come into contact with parts that can move when the engine is running,
such as the V-belt pulley or the fan.
XSecure the vehicle by applying the electric parking brake.
XShift the transmission to position j.
XMake sure that the ignition is switched off. All indicator lamps in the instrument cluster must be
off. When using the SmartKey, turn the SmartKey to position uin the ignition lock and remove it
(
Ypage 136).
XSwitch off all electrical consumers, e.g. rear window defroster, lighting, etc.
XOpen the hood.
326Jump-starting
Breakdown assistance

If your vehicle is being towed, much more
force may be necessary to steer or brake.
There is a risk of an accident.
In such cases, use a tow bar. Before towing,
make sure that the steering moves freely.
GWARNING
You can no longer steer the vehicle if the
steering wheel lock has been engaged. There
is a risk of an accident.
Always switch off the ignition when towing the
vehicle with a tow cable or a tow bar.
GWARNING
When towing or tow-starting another vehicle
and its weight is greater than the permissible
gross weight of your vehicle, the:
Rthe towing eye could detach itself
Rthe vehicle/trailer combination could roll-
over.
There is a risk of an accident.
When towing or tow-starting another vehicle,
its weight should not be greater than the per- missible gross weight of your vehicle.
Details on the permissible gross vehicle weight
of your vehicle can be found on the vehicle iden-
tification plate (
Ypage 360).
!When Active Brake Assist, Distance Pilot
DISTRONIC or the HOLD function is activated,
the vehicle brakes automatically in certain
situations.
To avoid damage to the vehicle, deactivate
these systems in the following or similar sit-
uations:
Rwhen towing the vehicle
Rin the car wash
!Make sure that the electric parking brake is
released. If the electric parking brake is faulty,
visit a qualified specialist workshop.
!Secure the tow rope or tow bar to the towing
eye only. Otherwise, the vehicle could
become damaged.
!Do not use the towing eye for recovery. This
could damage the vehicle. If in doubt, have
the vehicle recovered using a crane.
!When towing, pull away slowly and
smoothly. If the tractive power is too high, the
vehicles could be damaged.
!Shift the automatic transmission to position
i and do not open the driver's or front pas-
senger's door during towing. The automatic
transmission may otherwise shift to position
j, which could damage the transmission.
!Do not tow with sling-type equipment. This
could damage the vehicle.
!The vehicle can be towed a maximum of
30 miles (50km). The towing speed of 30 mph (50 km/h) must not be exceeded.
If the vehicle has to be towed more than
30 miles (50km), the entire vehicle must be
raised and transported.
It is better to have the vehicle transported than
to have it towed away.
If the vehicle has suffered transmission damage,
have it transported on a transporter or trailer.
The automatic transmission must be in position
i w

hen the vehicle is being towed. If the auto-
matic transmission cannot be shifted to position
i, have the vehicle transported on a trans-
porter or trailer.
The battery must be connected and charged.
Otherwise, you:
Rcannot turn the SmartKey to position 2in
the ignition lock
Rcannot release the electric parking brake
Rcannot shift the automatic transmission to
position i
Disarm the automatic locking feature before the vehicle is towed (
Ypage 85). You could other-
wise be locked out when pushing or towing the
vehicle.
Installing/removing the towing eye
Installing the towing eye
GWARNING
The exhaust tail pipe may be very hot. There is
a risk of burns when removing the rear cover.
Do not touch the exhaust pipe. Take particular
care when removing the rear cover.
328Towing and tow-starting
Breakdown assistance