2018 MERCEDES-BENZ C CLASS Owners Manual

multimedia system; see the Digital Operator's
Manual.
You will receive visual and acoustic locking con-
firmation if all components were able to be
locked.
When the locator lighting is activated via the
multimedia system, it lights up when it is dark
after the vehicle is unlocked with the SmartKey;
see the Digital Operator's Manual.
XTo open the trunk lid automatically from
outside the vehicle:press and hold theF
button until the trunk lid opens.
XTo open the trunk lid automatically from
outside the vehicle: if the SmartKey is loca-
ted in the immediate vicinity of the vehicle,
press the Fbutton on the SmartKey.
When the trunk lid closes you can then
release the button.
KEYLESS-GO
General notes
Bear in mind that the engine can be started by
any of the vehicle occupants if there is a Smart-
Key in the vehicle (
Ypage 138).
Locking/unlocking centrally
You can start, lock or unlock the vehicle using
KEYLESS-GO. To do this, you only need carry the
SmartKey with you. You can combine the func-
tions of KEYLESS-GO with those of a conven-
tional SmartKey. Unlock the vehicle by using
KEYLESS-GO, for instance, and lock it using the
& button on the SmartKey.
The driver's door and the door at which the han-
dle is used, must both be closed. The SmartKey
must be outside the vehicle. When locking or
unlocking with KEYLESS-GO, the distance
between the SmartKey and the corresponding
door handle must not be greater than 3 ft (1 m).
A brief radio connection between the vehicle
and the SmartKey determines whether a valid
SmartKey is in, or in the direct vicinity of, the
vehicle. This occurs, for example:
Rwhen starting the engine
Rwhile driving
Rwhen using HANDS-FREE ACCESS
Rwhen the external door handles are touched
Rduring convenience closing
XTo unlock the vehicle: touch the inner sur-
face of the door handle.
XTo lock the vehicle: touch sensor surface :
or ;.
Make sure that you do not touch the inner
surface of the door handle.
XConvenience closing feature: touch
recessed sensor surface ;for an extended
period.
Further information on the convenience clos-
ing feature (
Ypage 92).
XTo unlock the trunk lid: pull the handle on
the trunk lid.
Deactivating and activating
If you do not intend to use a SmartKey for an
extended period of time, you can deactivate the
KEYLESS-GO function of the SmartKey. The
SmartKey will then use very little power, thereby
conserving battery power. For the purposes of
activation/deactivation, the vehicle must not be
nearby.
XTo deactivate: press the&button on the
SmartKey twice in rapid succession.
The battery check lamp (
Ypage 81) of the
SmartKey flashes twice briefly and lights up
once, then KEYLESS-GO is deactivated.
XTo activate: press any button on the Smart-
Key.
or
XInsert the SmartKey into the ignition lock.
KEYLESS-GO and all of its associated features
are available again.
SmartKey79
Opening and closing
Z

KEYLESS-GOstart function
Gene ral notes
Bear in min dthat th eengin ecan be started by
any of th evehicl eoccupant sif there is aSmart -
Key in th evehicl e (
Ypage 138).
Changing the settings ofthe locking
system
You can chang eth esetting sof th elocking sys-
tem. This mean sthat only th edriver's door and
th efuel filler flap are unlocke dwhen th evehicl e
is unlocked. This is useful if you frequentl ytravel
alone.
XTo change th esetting: press and hold down
th e% and& buttons simultaneousl y
for approximately six seconds until th ebat -
tery chec klamp (
Ypage 81) flashes twice .
If th esetting of th elocking system is changed
within th esignal range of th evehicle, pressing
th e& or% button:
Rlocks or
Runlocks th evehicl e
The SmartKey no wfunction sas follows :
XTo unlock: press the% buttononce .
XTo unlock centrally: press the% button
twice .
XTo lock: press the& button.
XTo restor eth efactory settings: press and
hold th e% and& buttons simultane -
ousl yfor approximately six seconds until th e
battery chec klamp (
Ypage 81) flashes
twice .
The KEYLESS-GO function scan be changed as
follows :
XTo unlock th edriver's door :touch th einner
surfac eof th edoor handle on th edriver's
door .
XTo unlock centrally: touch theinner surfac e
of th edoor handle on th efront-passenger
door or there
ar door .
XTo lock centrally: touch theouter sensor
surfac eon on eof th edoor handles .
Mechanical key
Gene ral notes
If th evehicl ecan no longer be locke dor
unlocke dwit hth eSmartKey or KEYLESS-GO ,
use th emechanical key.
If you use th emechanical ke yto unloc kand
open th edriver's door ,th eanti-thef talarm sys-
te m will be triggered .Switc hoff th ealarm
(
Ypage 76) .
If you unloc kth evehicl eusin gth emechanical
key, th efuel filler flap will no tbe unlocke dauto -
matically.
XTo unlock th efuel filler flap: insert the
SmartKey int oth eignition lock.
Removing the mechanical key
XPush release catch :in th edirection of th e
arrow and at th esam etime remove mechan -
ical ke y; from th eSmartKey.
Further information on locking/unlocking th e
driver's door (
Ypage 85).
Inserting the mechanical key
XPush mechanical ke y; completely int oth e
SmartKey until it engage sand release
catch :is bac kin it sbasic position .
SmartKey battery
Import ant safety notes
GWARNIN G
Batterie scontain toxic and corrosiv esubstan -
ces. If batterie sare swallowed, it can result in
80SmartKey
Opening and closing

severe health problems. There is a risk of fatalinjury.
Keep batteries out of the reach of children. If
a battery is swallowed, seek medical attention immediately.
HEnvironmental note
Batteries contain dangerous
substances. It is against the
law to dispose of them with
the household rubbish. They
must be collected separatelyand recycled to protect the
environment.
Dispose of batteries in an
environmentally friendly
manner. Take discharged
batteries to a qualified spe-
cialist workshop or a special
collection point for used bat-
teries.
The SmartKey batteries contain perchlorate
material, which may require special handling
and regard for the environment. National guide-
lines must be observed during disposal. In Cal-
ifornia, see www.dtsc.ca.gov/
HazardousWaste/Perchlorate/index.cfm.
Mercedes-Benz recommends that you have the
batteries replaced at a qualified specialist work-
shop.
Checking the battery
XPress the &or% button.
The battery is working properly if battery
check lamp :lights up briefly. The battery is discharged if battery check
lamp
:does not light up briefly.
XChange the battery (Ypage 81).
If the SmartKey battery is checked within the
signal reception range of the vehicle, pressing
the & or% button:
Rlocks or
Runlocks the vehicle
iYou can get a battery at any qualified spe-
cialist workshop.
Replacing the battery
You require a CR 2025 3 V cell battery.
XTake the mechanical key out of the SmartKey
(Ypage 80).
XPress mechanical key ;into the SmartKey
opening in the direction of the arrow until bat-
tery compartment cover :opens. Do not
hold battery compartment cover :closed
while doing so.
XRemove battery compartment cover :.
SmartKey81
Opening and closing
Z

XRepeatedly tap theSmartKey against your
palm until battery =falls out .
XInsertth ene wbattery wit hth epositive ter-
minal facing upwards. Use alint-free cloth to
do so.
XMak esur ethat th esurfac eof th ebattery is
free of lint, grease and other contaminants.
XInser tth efron ttab sof battery compartmen t
cover :intoth ehousing first and then press
to close it .
XInsertmechanical ke y; intoth eSmartKey
(Ypage 80).
XChec kth efunction of all SmartKey buttons on
th evehicle.
Problems with the SmartKey
ProblemPossible causes/consequences and MSolutions
You can no longer lockor
unlock th evehicl eusin g
th eSmartKey.The SmartKey battery is discharged or nearly discharged.
XChec kth eSmartKey battery (Ypage 81) and replace it if necessar y
(Ypage 81).
If this does no twork:
XLoc kor unlock th evehicl eusin gth emechanical ke y (Ypage 85).
There is interferenc efrom apowerful source of radi owaves.
XLoc kor unlock th evehicl eusin gth emechanical ke y (Ypage 85).
The SmartKey is faulty.
XLockor unlock th evehicl eusin gth emechanical ke y (Ypage 85).
XHaveth eSmartKey checke dat aqualified specialist workshop.
You can no longer loc kor
unlock th evehicl eusin g
KEYLESS-GO .KEYLESS-GO was deactivated.
XReactivateKEYLESS-GO (Ypage 79).
The SmartKey battery is discharged or nearly discharged.
XCheckth eSmartKey battery (Ypage 81) and replace it if necessar y
(Ypage 81).
If this does no twork:
XLoc kor unlock th evehicl eusin gth emechanical ke y (Ypage 85).
There is interferenc efrom apowerful source of radi owaves.
XLoc kor unlock th evehicl eusin gth emechanical ke y (Ypage 85).
82SmartKey
Opening and closing

ProblemPossible causes/consequences andMSolutions
KEYLESS-GO is malfunctioning.
XLock/unlock the vehicle using the remote control function of the
SmartKey.
XHave the vehicle and SmartKey checked at a qualified specialist
workshop.
If the vehicle can also not be locked/unlocked using the remote con-
trol function:
XLock or unlock the vehicle using the mechanical key (Ypage 85).
XHave the vehicle and SmartKey checked at a qualified specialist
workshop.
The engine cannot be
started using the Smart-
Key.The on-board voltage is too low.
XSwitch off non-essential consumers, e.g. seat heating or interior
lighting, and try to start the engine again.
If this does not work:
XCheck the starter battery and charge it if necessary (Ypage 324).
or
XJump-start the vehicle (Ypage 325).
or
XConsult a qualified specialist workshop.
The engine cannot be
started using the Start/
Stop button. The Smart-
Key is in the vehicle.The vehicle is locked.
XUnlock the vehicle and try to start the vehicle again.
The SmartKey battery is discharged or nearly discharged.
XCheck the SmartKey battery (Ypage 81) and replace it if necessary
(Ypage 81).
If this does not work:
XStart your vehicle with the SmartKey in the ignition lock.
There is interference from a powerful source of radio waves.
XStart your vehicle with the SmartKey in the ignition lock.
You have lost a Smart-
Key.XHave the SmartKey deactivated at a qualified specialist workshop.
XReport the loss immediately to the vehicle insurers.
XIf necessary, have the locks changed as well.
You have lost the
mechanical key.XReport the loss immediately to the vehicle insurers.
XIf necessary, have the locks changed as well.
SmartKey83
Opening and closing
Z

Doors
Important safet ynotes
GWARNING
If children are lef tunsupervised in th evehicle,
they could:
Rope nth edoors ,thus endangerin gother
people or road users.
Rget out and disrup ttraffic .
Roperat eth evehicle' sequipment.
Additionally, children could set th evehicle in
motion if, fo rexample, they:
Rrelease th eparking brake .
Rshiftingth eautomatic transmissio nout of
par kposition P
RStart theengine.
There is aris kof an acciden tand injury.
Whe nleavin gth evehicle, always take th e
SmartKey wit hyou and loc kth evehicle. Never
leav echildren or animals unattended in th e
vehicle. Always keep th eSmartKey out of
reach of children .
Unlockingan dopening doors from
th einside
You can ope n adoo rfrom insid eth evehicle
eve nif it has bee nlocked. You can only ope nth e
rea rdoors from insid eth evehicle if they are no t
secure dby th echild-proof locks (
Ypage 65). If
th evehicle has bee nlocke dwit hth eSmartKey
or wit hKEYLESS-GO ,opening adoo rfrom th e
insid ewill trigger th eanti-thef talar msystem.
Switc hof fth ealar m (
Ypage 76) .
XTo unlock an dope n afront door: pull door
handle ;.
If th edoo ris locked, locking knob :pop sup.
The doo ris unlocke dand opens .
XTo unlock arear door: pull reardoo rhandle.
The locking knob on th erea rdoo rpop sup and
th erea rdoo runlocks .
XTo open arear door: pull reardoo rhandle
again .
The rea rdoo ropens .
Centrally locking an dunlocking th e
vehicle from th einside
You can centrall yloc kand unloc kth evehicle
from th einside. The switches are on th edriver’s
door.
XTo unlock :press butto n:.
XTo lock :press butto n;.
Whe nth efront-passenger doo ris closed, th e
vehicle is locked.
Meanwhile, th efue lfiller flap will no tbe locke d
or unlocked.
You canno tunloc kth evehicle centrall yfrom th e
insid eif th evehicle has bee nlocke dwit hth e
SmartKey or KEYLESS-GO .
The doors can be opene dfrom th einside. You
can only ope nth erea rdoors from insid eth e
vehicle if they are no tsecure dby th echild-proof
locks (
Ypage 65).
If th evehicle has bee nlocke dwit hth eSmartKey
or wit hKEYLESS-GO ,opening adoo rfrom th e
insid ewill trigger th eanti-thef talar msystem.
Switc hof fth ealar m (
Ypage 76).
84Doors
Opening and closing

If a locked door is opened from the inside, the
previous unlock status of the vehicle will be
taken into consideration if:
Rthe vehicle was locked using the locking but-
ton for the central locking, or
Rthe vehicle was locked automatically
The vehicle will be fully unlocked if it had previ-
ously been fully unlocked. If only the driver's
door had been previously unlocked, only the
door which has been opened from the inside is
unlocked.
Automatic locking feature
XTo deactivate: press and hold button :for
approximately five seconds until a tone
sounds.
XTo activate: press and hold button ;for
approximately five seconds until a tone
sounds.
If you press one of the two buttons and do not
hear a tone, the relevant setting has already
been selected.
The vehicle is locked automatically when the
ignition is switched on and the wheels are turn-
ing.
You could therefore be locked out if:
Rthe vehicle is being pushed
Rthe vehicle is being towed
Rthe vehicle is being tested on a dynamometer.
You can activate and deactivate the automatic
locking mechanism via the multimedia system
(see the Digital Operator's Manual).
Locking/unlocking the driver's door
with the mechanical key
i
If you want to centrally lock the vehicle using
the mechanical key, begin by pressing the
locking button for the interior locking mech-
anism while the driver's door is open. Then
lock the driver's door using the mechanical
key.
XInsert the mechanical key into opening :in
the protective cap.
XPull and hold the door handle.
XPull the protective cap on the mechanical key
as straight as possible away from the vehicle
until it releases.
XRelease the door handle.
XTo lock: turn the mechanical key clockwise as
far as it will go to position 1.
XTo unlock:turn the mechanical key counter-
clockwise as far as it will go to position 1.
If you use the mechanical key to unlock and
open the driver's door, the anti-theft alarm sys-
tem will be triggered. Switch off the alarm
(
Ypage 76).
Doors85
Opening and closing
Z

Trunk
Important safety notes
GWARNING
Combustion engines emit poisonous exhaust
gases such as carbon monoxide. Exhaust
gases can enter the vehicle interior if the
trunk lid is open when the engine is running,
especially if the vehicle is in motion. There is a
risk of poisoning.
Always switch off the engine before opening
the trunk lid. Never drive with the trunk lid
open.
GWARNING
If objects, luggage or loads are not secured or
not secured sufficiently, they could slip, tip
over or be flung around and thereby hit vehicle
occupants. There is a risk of injury, particu-
larly in the event of sudden braking or a sud-
den change in direction.
Always store objects so that they cannot be
flung around. Secure objects, luggage or
loads against slipping or tipping before the
journey.
!The trunk lid swings upwards when opened.
Therefore, make sure that there is sufficient
clearance above the trunk lid.
The opening dimensions of the trunk lid can be
found in the "Vehicle data" section
(
Ypage 367).
You can limit the opening angle of the trunk lid in
the multimedia system; see the Digital Opera-
tor's Manual.
Do not leave the SmartKey in the trunk. You
could otherwise lock yourself out.
You should preferably place luggage or loads in
the trunk. Observe the loading guidelines
(
Ypage 280).
Object detection with trunk lid revers-
ing feature
Vehicles with trunk lid remote closing fea-
ture:
The trunk lid is equipped with automatic object
detection with a reversing feature. If a solid object blocks or restricts the trunk lid when
automatically opening, this procedure is stop-
ped. If a solid object blocks or restricts the trunk
lid when automatically closing, the trunk lid
opens again automatically. Automatic object
detection with reversing function is only an aid.
It is not a substitute for your attentiveness when opening and closing the trunk lid.
GWARNING
The reversing feature does not respond:
Rto soft, light and thin objects, e.g. fingers
Rover the last 1/3 in (8 mm) of the closing
movement
The reversing feature cannot prevent some-
one being trapped in these situations in par-
ticular. There is a risk of injury.
Make sure that no body parts are in close
proximity during the closing procedure.
If somebody becomes trapped:
Rpress the Fbutton on the SmartKey, or
Rpull or press the remote operating switch
on the driver's door or
Rpress the closing or locking button on the
trunk lid, or
Rpull on the trunk lid handle
Vehicles with HANDS-FREE ACCESS:
It is also possible to stop the closing process by
performing a kicking movement under the rear
bumper.
Opening and closing manually
Opening
86Trunk
Opening and closing