2015 MERCEDES-BENZ C-Class SEDAN Keyless

onds until the battery check lamp flashes
twice (Y
page 84). Mechanical key
General notes If the vehicle can no longer be locked or
unlocked with the SmartKey or KEYLESS-GO,
use the mechanical key.
If you use the mechanical key to unlock and
open the driver's door, the anti-theft alarm
system will be triggered. Switch off the alarm
(Y page 76).
If you unlock the vehicle using the mechanical key, the fuel filler flap will not be unlocked
automatically.
X To unlock the fuel filler flap: insert the
SmartKey into the ignition lock.
Removing the mechanical key X
Push release catch 0043in the direction of
the arrow and at the same time remove
mechanical key 0044from the SmartKey.
For further information about: R unlocking the driver's door (Y page 88)
R unlocking the trunk (Y page 96)
R locking the vehicle (Y page 89)
Inserting the mechanical key X
Push mechanical key 0044completely into
the SmartKey until it engages and release
catch 0043is back in its basic position. SmartKey battery
Important safety notes G
WARNING
Batteries contain toxic and corrosive substan- ces. If batteries are swallowed, it can result in
severe health problems. There is a risk of fatal injury.
Keep batteries out of the reach of children. If
a battery is swallowed, seek medical attention immediately. H
Environmental note Batteries contain dangerous
substances. It is against the
law to dispose of them with
the household rubbish. They
must be collected separately
and 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
guidelines must be observed during disposal.
In California, see www.dtsc.ca.gov/
HazardousWaste/Perchlorate/
index.cfm.
Mercedes-Benz recommends that you have
the batteries replaced at a qualified specialist workshop. SmartKey
83Opening and closing Z

Problems with the SmartKey
Problem
Possible causes/consequences and
0050
0050Solutions You can no longer lock
or unlock the vehicle
using the SmartKey. The SmartKey battery is discharged or nearly discharged.
X Check the SmartKey battery (Y page 84) and replace it if nec-
essary (Y page 84).
If this does not work:
X Unlock (Y page 88) or lock (Y page 89) the vehicle using the
mechanical key. There is interference from a powerful source of radio waves.
X Unlock (Y page 88) or lock (Y page 89) the vehicle using the
mechanical key. The SmartKey is faulty.
X Unlock (Y page 88) or lock (Y page 89) the vehicle using the
mechanical key.
X Have the SmartKey checked at a qualified specialist workshop. You can no longer lock
or unlock the vehicle
using KEYLESS-GO. KEYLESS-GO was deactivated.
X Reactivate KEYLESS-GO (Y page 81). The SmartKey battery is discharged or nearly discharged.
X Check the SmartKey battery (Y page 84) and replace it if nec-
essary (Y page 84).
If this does not work:
X Unlock (Y page 88) or lock (Y page 89) the vehicle using the
mechanical key. There is interference from a powerful source of radio waves.
X Unlock (Y page 88) or lock (Y page 89) the vehicle using the
mechanical key. KEYLESS-GO is malfunctioning.
X Lock/unlock the vehicle using the remote control function of
the SmartKey.
X Have the vehicle and SmartKey checked at a qualified specialist
workshop.
If the vehicle can also not be locked/unlocked using the remote
control function:
X Unlock (Y page 88) or lock (Y page 89) the vehicle using the
mechanical key.
X Have the vehicle and SmartKey checked at a qualified specialist
workshop. SmartKey
85Opening and closing Z

Doors
Important safety notes
G
WARNING
If children are left unsupervised in the vehicle, they could:
R open the doors, thus endangering other
people or road users.
R get out and disrupt traffic.
R operate the vehicle's equipment.
Additionally, children could set the vehicle in
motion if, for example, they:
R release the parking brake.
R shifting the automatic transmission out of
park position P
R Start the engine.
There is a risk of an accident and injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children or animals unattended in the
vehicle. Always keep the SmartKey out of
reach of children.
You should preferably place luggage or loads in the trunk. Observe the loading guidelines
(Y page 298). Unlocking and opening doors from
the inside
You can open a door from inside the vehicle
even if it has been locked. You can only open
the rear doors from inside the vehicle if they
are not secured by the child-proof locks
(Y page 65). If the vehicle has been locked
with the SmartKey or with KEYLESS-GO,
opening a door from the inside will trigger the
anti-theft alarm system. Switch off the alarm
(Y page 76). X
To unlock and open a front door: pull
door handle 0044.
If the door is locked, locking knob 0043pops
up. The door is unlocked and opens.
X To unlock a rear door: pull door han-
dle 0044.
Locking knob 0043pops up and the door
unlocks.
X To open a rear door: pull door handle0044
again.
The door opens. Centrally locking and unlocking the
vehicle from the inside
You can centrally lock and unlock the vehicle from the inside. The switches are on the
driver’s door. X
To unlock: press button 0043.
X To lock: press button 0044.
If the front-passenger door is closed, the
vehicle locks. Doors
87Opening and closing Z

Meanwhile, the fuel filler flap will not be
locked or unlocked.
You cannot unlock the vehicle centrally from
the inside if the vehicle has been locked with the SmartKey or KEYLESS-GO.
The doors can be opened from the inside. You
can only open the rear doors from inside the
vehicle if they are not secured by the child-
proof locks (Y page 65).
If the vehicle has been locked with the Smart-
Key or with KEYLESS-GO, opening a door from the inside will trigger the anti-theft alarm sys-
tem. Switch off the alarm (Y page 76).
If a locked door is opened from the inside, the previous unlock status of the vehicle will be
taken into consideration if:
R the vehicle was locked using the locking
button for the central locking, or
R if the vehicle was locked automatically
The vehicle will be fully unlocked if it had pre- viously 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
X
To deactivate: press and hold button 0043
for approximately five seconds until a tone sounds.
X To activate: press and hold button 0044for
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
turning.
You could therefore be locked out if:
R the vehicle is being pushed.
R the vehicle is being towed.
R the vehicle is on a roller dynamometer.
i You can also activate and deactivate the
automatic locking function via COMAND or
Audio 20 (see the separate operating
instructions). Unlocking the driver's door (mechan-
ical key)
If the vehicle can no longer be locked or
unlocked with the SmartKey or KEYLESS-GO, use the mechanical key.
X Take the mechanical key out of the Smart-
Key (Y page 83).
Vehicles with KEYLESS-GO: X Insert the tip of the mechanical key into the
slit on the cover of the driver's door lock
and turn it until the cover is released. X
Insert the mechanical key into the lock of
the driver's door as far as it will go.
X Turn the mechanical key counter-clockwise
as far as it will go to position 0047.
The locking knob pops up and the door
unlocks. 88
DoorsOpening and closing

X
Turn the mechanical key back and remove
it.
X Insert the mechanical key into the Smart-
Key.
X Hold the cover over the lock of the driver's
door with the thicker end towards the front of the vehicle and press to secure. Then
make sure that the slit of the cover is hor-
izontal.
Vehicles without KEYLESS-GO: X
Insert the mechanical key into opening 0043
in the protective cap.
X Pull and hold the door handle.
X Pull the protective cap on the mechanical
key as straight as possible away from the
vehicle until it releases.
X Release the door handle. X
Insert the mechanical key into the lock of
the driver's door as far as it will go.
X Turn the mechanical key counter-clockwise
as far as it will go to position 0047.
The locking knob pops up and the door
unlocks. X
Turn the mechanical key back and remove
it.
X Insert the mechanical key into the Smart-
Key (Y page 83).
X Carefully press the protective cap onto the
lock cylinder until it engages and is seated firmly. Do not pull the door handle when
doing so.
All vehicles:
If you use the mechanical key to unlock and
open the driver's door, the anti-theft alarm
system will be triggered. Switch off the alarm
(Y page 76). Locking the vehicle (mechanical key)
If the vehicle can no longer be locked with the SmartKey or KEYLESS-GO, use the mechani-
cal key.
X Open the driver's door.
X Close the front-passenger door, the rear
doors and the trunk lid.
X Press the locking button (Y page 87).
X Check whether the locking knobs on the
front-passenger door and the rear doors
are still visible. Press down the locking
knobs by hand, if necessary.
X Close the driver's door.
X Take the mechanical key out of the Smart-
Key (Y page 83).
Vehicles with KEYLESS-GO: X Insert the tip of the mechanical key into the
slit on the cover of the driver's door lock
and turn it until the cover is released. Doors
89Opening and closing Z

X
Insert the mechanical key into the lock of
the driver's door as far as it will go.
X Turn the mechanical key clockwise as far as
it will go to position 0047.
The locking knob drops down and the driv- er's door is locked.
X Turn the mechanical key back and remove
it.
X Insert the mechanical key into the Smart-
Key.
X Make sure that the doors and the trunk lid
are locked.
X Hold the cover over the lock of the driver's
door with the thicker end towards the front of the vehicle and press to secure. Then
make sure that the slit of the cover is hor-
izontal.
Vehicles without KEYLESS-GO: X
Insert the mechanical key into opening 0043
in the protective cap.
X Pull and hold the door handle. X
Pull the protective cap on the mechanical
key as straight as possible away from the
vehicle until it releases.
X Release the door handle. X
Insert the mechanical key into the lock of
the driver's door as far as it will go.
X Turn the mechanical key clockwise as far as
it will go to position 0047.
The locking knob drops down and the driv- er's door is locked.
X Turn the mechanical key back and remove
it.
X Insert the mechanical key into the Smart-
Key (Y page 83).
X Make sure that the doors and the trunk lid
are locked.
X Carefully press the protective cap onto the
lock cylinder until it engages and is seated
firmly. Do not pull the door handle when
doing so.
All vehicles:
If you lock the vehicle as described above, the fuel filler flap is not locked. The anti-theft
alarm system is not armed. Trunk
Important safety notes
G
WARNING
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, 90
TrunkOpening and closing

X
Press the 0054button on the SmartKey.
or X Pull handle 0043.
The trunk lid opens.
Closing X
Pull the trunk lid down using recess 0043and
push it closed.
X Lock the vehicle if necessary with the 0037
button on the SmartKey or with KEYLESS-
GO (Y page 81). Opening/closing automatically from
outside
Important safety notes G
WARNING
Parts of the body could become trapped dur-
ing automatic closing of the trunk lid. More-
over, people, e.g. children, may be standing in the closing area or may enter the closing area
during the closing process. There is a risk of
injury.
Make sure that nobody is in the vicinity of the closing area during the closing process.
Use one of the following options to stop the
closing process:
R Press the 0054button on the key.
R press the remote operating switch on the
driver's door. R
Press the closing or locking button on the
trunk lid.
R Pull 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. G
WARNING
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.
! 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
(Y page 403).
Opening You can open the trunk lid automatically
using the SmartKey or the handle in the trunk
lid.
X Press and hold the 0054button on the
SmartKey until the trunk lid opens.
or X If the trunk lid is unlocked, pull the trunk lid
handle and let it go again immediately. 92
TrunkOpening and closing

Closing
X
Press closing button 0043on the trunk lid.
Vehicles with trunk lid remote closing
feature and KEYLESS-GO: when the driver's
door is closed you can simultaneously close
the trunk lid and lock the vehicle. The KEY-
LESS-GO key must be in the rear detection
range of the vehicle.
X Press locking button 0044in the trunk lid.
If KEYLESS-GO detects a SmartKey outside the vehicle, the trunk lid closes and the
vehicle is locked.
If KEYLESS-GO detects a SmartKey in the
trunk, the trunk lid opens again after it is
closed.
If KEYLESS-GO detects a second SmartKey
outside the vehicle, the trunk lid remains
closed. Opening automatically from outside
Important safety notes G
WARNING
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. !
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 printed Operator's Manual. HANDS-FREE ACCESS
Important safety notes G
WARNING
The vehicle's exhaust system may be very hot. You could burn yourself by touching the
exhaust system if you use HANDS-FREE
ACCESS. There is a risk of injury. Always
ensure that you only make the kicking move-
ment within the detection range of sensors.
! If the SmartKey is within the rear detec-
tion range of KEYLESS-GO, the following
situations, for example, could lead to the
unintentional opening of the trunk:
R using a car wash
R using a power washer
Make sure that the SmartKey is at least
10 ft (3m) away from the vehicle.
General notes With KEYLESS-GO and HANDS-FREE
ACCESS, you can open or close the trunk lid
or stop the procedure without using your
hands. This is useful if you have your hands
full. To do this, make a kicking movement
under the bumper with your foot.
Observe the following points:
R Carry your KEYLESS-GO key about your
person. The KEYLESS-GO key must be in
the rear detection range of the vehicle.
R When making the kicking movement, make
sure that you are standing firmly on the
ground and that there is sufficient clear-
ance to the rear of the vehicle. You could
otherwise lose your balance e.g. on ice. Trunk
93Opening and closing Z