2015 MERCEDES-BENZ C-Class SEDAN Owner's Manual

Useful information
..............................80
SmartKey ............................................. 80
Doors .................................................... 87
Trunk .................................................... 90
Side windows ...................................... 97
Sliding sunroof .................................. 101 79Opening and closing

Useful information
i This Operator's Manual describes all
models and all standard and optional equip- ment of your vehicle available at the time of
publication of the Operator's Manual.
Country-specific differences are possible.
Please note that your vehicle may not be
equipped with all features described. This
also applies to safety-related systems and
functions.
i Read the information on qualified special-
ist workshops (Y page 26). SmartKey
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. G
WARNING
If you attach heavy or large objects to the
SmartKey, the SmartKey could be uninten-
tionally turned in the ignition lock. This could
cause the engine to be switched off. There is a risk of an accident. Do not attach any heavy or large objects to the
SmartKey. Remove any bulky key rings before
inserting the SmartKey into the ignition lock.
! Keep the SmartKey away from strong
magnetic fields. Otherwise, the remote
control function could be affected.
Strong magnetic fields can occur in the
vicinity of powerful electrical installations.
Do not keep the SmartKey: R with electronic devices, e.g. a mobile
phone or another SmartKey
R with metallic objects, e.g. coins or metal
foil
R inside metallic objects, e.g. a metal case
This can affect the functionality of the
SmartKey.
Vehicles with KEYLESS-GO start function: do not keep the SmartKey on the parcel shelf or in the trunk. Otherwise, the SmartKey maynot be detected, e.g. when starting the engine
using the Start/Stop button.
A check which periodically establishes a radio
connection between the vehicle and the
SmartKey determines whether a valid Smart- Key is in the vehicle. This occurs, for example:
R when starting the engine
R whilst driving
R when the external door handles are
touched
R during convenience closing 80
SmartKeyOpening and closing

SmartKey functions
0043
0037 Locks the vehicle
0044 0054 Opens/closes the trunk lid
0087 0036 Unlocks the vehicle
X To unlock centrally: press button0087.
If you do not open the vehicle within
approximately 40 seconds of unlocking:
R the vehicle is locked again.
R protection against theft is reactivated.
X To lock centrally: press button0043.
The SmartKey centrally locks/unlocks: R the doors
R the trunk lid
R the fuel filler flap
The turn signals flash once when unlocking
and three times when locking.
You can also set an audible signal to confirm that the vehicle has been locked. The audiblesignal can be activated and deactivated via
COMAND or Audio 20 (see the separate oper-
ating instructions).
When the locator lighting is activated via
COMAND or Audio 20, it lights up when it is
dark after the vehicle is unlocked with the
remote control (see the separate operating
instructions).
X To open the trunk lid automatically
from outside the vehicle: press and hold
button 0044until the trunk lid opens.
X To open the trunk lid automatically
from outside the vehicle: if the SmartKeyis in close proximity to the vehicle: press
the
0054 button on the SmartKey.
You can release the button as soon as the
trunk lid starts to close. KEYLESS-GO
General notes Bear in mind that the engine can be started by
any of the vehicle occupants if there is a
SmartKey in the vehicle.
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
functions of KEYLESS-GO with those of a con- ventional SmartKey. Unlock the vehicle by
using KEYLESS-GO, for instance, and lock it
using the 0037button on the SmartKey.
The driver's door and the door at which the
handle 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 cor-
responding door handle must not be greater
than 3 ft (1 m).
A check which periodically establishes a radio
connection between the vehicle and the
SmartKey determines whether a valid Smart- Key is in the vehicle. This occurs, for example:
R when starting the engine
R whilst driving
R when the external door handles are
touched
R during convenience closing SmartKey
81Opening and closing Z

X
To unlock the vehicle: touch the inner
surface of the door handle.
X To lock the vehicle: touch sensor sur-
face 0043or0044.
Make sure that you do not touch the inner
surface of the door handle.
X Convenience closing feature: touch
recessed sensor surface 0044for an exten-
ded period.
Further information on the convenience
closing feature (Y page 99).
X To unlock the trunk lid: pull the handle on
the trunk lid.
Deactivating If you do not intend to use the vehicle for a
longer period of time, you can deactivate KEY- LESS-GO. The SmartKey will then use very lit-
tle power, thereby conserving battery power.
For the purposes of activation/deactivation,
the vehicle must not be nearby.
X To deactivate: press the0037button on
the SmartKey twice in rapid succession.
The battery check lamp of the SmartKey
lights up twice briefly and KEYLESS-GO is
deactivated.
X To activate: press any button on the
SmartKey or insert the SmartKey into the
ignition lock.
KEYLESS-GO and all of its associated fea-
tures are available again. KEYLESS-GO start function
Bear in mind that the engine can be started by any of the vehicle occupants if there is a
SmartKey in the vehicle. Changing the settings of the locking
system
You can change the settings of the locking
system. This means that only the driver's door and the fuel filler flap are unlocked when the
vehicle is unlocked. This is useful if you fre-
quently travel on your own.
X To change the setting: press and hold
down the 0036and0037 buttons simulta-
neously for approximately six seconds until
the battery check lamp flashes twice
(Y page 84).
If the setting of the locking system is changed
within the signal range of the vehicle, press-
ing the 0037or0036 button:
R locks or
R unlocks the vehicle
The SmartKey now functions as follows:
X To unlock the driver's door: press the
0036 button once.
X To unlock centrally: press the0036but-
ton twice.
X To lock centrally: press the0037button.
The KEYLESS-GO function is changed as fol-
lows:
X To unlock the driver's door: touch the
inner surface of the door handle on the
driver's door.
X To unlock centrally: touch the inner sur-
face of the door handle on the front-
passenger door or the rear door.
X To lock centrally: touch the outer sensor
surface on one of the door handles.
X To restore the factory settings: press
and hold down the 0036and0037 buttons
simultaneously for approximately six sec- 82
SmartKeyOpening and closing

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

Checking the battery
X
Press the 0037or0036 button.
The battery is working properly if battery
check lamp 0043lights up briefly.
The battery is discharged if battery check
lamp 0043does not light up briefly.
X Change the battery (Y page 84).
If the key battery is checked within the signal
reception range of the vehicle, pressing the
0037 or0036 button:
R locks or
R unlocks the vehicle
i You can obtain a battery from any quali-
fied specialist workshop.
Replacing the battery You require a CR 2025 3 V cell battery.
X Take the mechanical key out of the Smart-
Key (Y page 83). X
Press mechanical key 0044into the opening
in the SmartKey in the direction of the
arrow until battery compartment cover 0043opens. Do not hold battery compartment
cover
0043closed while doing so.
X Remove battery compartment cover 0043. X
Repeatedly tap the SmartKey against your
palm until battery 0087falls out.
X Insert the new battery with the positive ter-
minal facing upwards. Use a lint-free cloth
to do so.
X Make sure that the surface of the battery is
free of lint, grease and other contaminants.
X Insert the front tabs of battery compart-
ment cover 0043into the housing first and
then press to close it.
X Insert mechanical key 0044into the Smart-
Key.
X Check the function of all SmartKey buttons
on the vehicle. 84
SmartKeyOpening and closing

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

Problem
Possible causes/consequences and
0050
0050Solutions The engine cannot be
started using the
SmartKey. The on-board voltage is too low.
X Switch off non-essential consumers, e.g. seat heating or interior
lighting, and try to start the engine again.
If this does not work:
X Check the starter battery and charge it if necessary
(Y page 347).
or
X Jump-start the vehicle (Y page 349).
or
X Consult a qualified specialist workshop. The engine cannot be
started using the Start/
Stop button. The
SmartKey is in the vehi-
cle. The vehicle is locked.
X Unlock the vehicle and try to start the vehicle again. 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 Start your vehicle with the SmartKey in the ignition lock. There is interference from a powerful source of radio waves.
X Start your vehicle with the SmartKey in the ignition lock. You have lost a Smart-
Key. X
Have the SmartKey deactivated at a qualified specialist work-
shop.
X Report the loss immediately to the vehicle insurers.
X If necessary, have the locks changed as well. You have lost the
mechanical key. X
Report the loss immediately to the vehicle insurers.
X If necessary, have the locks changed as well. 86
SmartKeyOpening and closing