2015 MERCEDES-BENZ C-Class COUPE change key battery

The turn signals flash once when unlocking
and three times when locking.
When it is dark, the surround lighting also
comes on if it is activated in the on-board
computer (Y page 202).
You can also set an audible signal to confirm that the vehicle has been locked. The audiblesignal can be activated and deactivated using
the on-board computer (Y page 203).
X To unlock centrally: press the0036but-
ton.
If you do not open the vehicle within approx-
imately 40 seconds of unlocking:
R the vehicle is locked again.
R the theft deterrent locking system is armed
again.
X To lock centrally: press the0037button. KEYLESS-GO
General notes Bear in mind that the engine can be started by
any of the vehicle occupants if there is a KEY-LESS-GO key 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.
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). KEYLESS-GO checks whether a valid Smart-
Key is in the vehicle by periodically establish-
ing a radio connection between the vehicle
and the SmartKey. This happens:
R when the external door handles are
touched
R when starting the engine
R while the vehicle is in motion X
To unlock the vehicle: touch the inner
surface of the door handle.
X To lock the vehicle: touch sensor sur-
face 0043.
X Convenience closing feature: touch
recessed sensor surface 0044for an exten-
ded period.
Further information on the convenience clos-
ing feature (Y page 87).
If you pull on the handle of the trunk lid, only the trunk of the vehicle is unlocked. 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 (Y page 77)
flashes twice. SmartKey
75Opening and closing Z

i
If the setting of the locking system is
changed within the signal range of the vehi- cle, pressing 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 front-passenger door handle.
X To lock centrally: touch the outer sensor
surface on one of the door handles
(Y page 75).
X To restore the factory settings: press
and hold down the 0036and0037 buttons
simultaneously for approximately six sec-
onds until the battery check lamp flashes
twice. Mechanical key
General notes If the vehicle can no longer be locked or
unlocked with the SmartKey or the KEYLESS- GO key, use the mechanical key.
If you use the mechanical key to unlock and
open the driver's door or the trunk lid, the
anti-theft alarm system will be triggered
(Y page 72).
X To end the alarm: insert the SmartKey into
the ignition lock.
i With KEYLESS-GO:
remove the Start/
Stop button from the ignition lock before-
hand. 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.
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 Mercedes-Benz recommends that you have
the batteries replaced at a qualified specialist
workshop. 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. 76
SmartKeyOpening and closing

Checking the battery
X
Press the 0037or0036 button.
The battery is working properly if battery
check lamp 0043lights up briefly.
If battery check lamp 0043does not light up
briefly during the test, the battery is dis-
charged.
i If the SmartKey battery is checked within
the signal reception range of the vehicle,
pressing the 0037or0036 button:
R locks or
R unlocks the vehicle
X Change the battery (Y page 77).
i You can get a battery at a qualified spe-
cialist 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 76). X
Press mechanical key 0044into the SmartKey
opening in the direction of the arrow until
battery compartment cover 0043opens. Do
not hold battery compartment cover 0043
closed 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 (Y page 76).
X Check the function of all SmartKey buttons
on the vehicle. SmartKey
77Opening and closing Z

Problems with the SmartKey
Problem
Possible causes/consequences and
0050
0050Solutions You cannot lock or
unlock the vehicle
using the SmartKey. The SmartKey battery is discharged or nearly discharged.
X Try again to lock/unlock the vehicle using the remote control
function of the SmartKey. Point the tip of the SmartKey at the
driver's door handle from close range and press the 0036or
0037 button.
If this does not work:
X Check the SmartKey battery (Y page 77) and replace it if nec-
essary (Y page 77).
X Lock (Y page 81) or unlock (Y page 81) the vehicle using the
mechanical key. The SmartKey is faulty.
X Lock (Y page 81) or unlock (Y page 81) 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. There is interference from a powerful source of radio waves.
X Lock/unlock the vehicle using the remote control function of
the SmartKey. Point the tip of the SmartKey at the driver's door
handle from close range and press the 0036/0037 button. There is a malfunction with KEYLESS-GO.
X Lock/unlock the vehicle using the remote control function of
the SmartKey. Point the tip of the SmartKey at the driver's door
handle from close range and press the 0036/0037 button.
X Have KEYLESS-GO checked at a qualified specialist workshop.
If this does not work: X Check the SmartKey battery (Y page 77) and replace it if nec-
essary (Y page 77).
X Lock (Y page 81) or unlock (Y page 81) the vehicle using the
mechanical key. 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. 78
SmartKeyOpening and closing

Display messages
Possible causes/consequences and
0050
0050Solutions 00AF
Obtain a New Key Obtain a New Key The SmartKey needs to be replaced.
X Visit a qualified specialist workshop. 00AF
Replace Replace
Key
KeyBattery
Battery The batteries of the KEYLESS-GO key are discharged.
X Change the batteries (Y page 77).00AF
Don't Forget Your Don't Forget Your
Key Key The display message is shown for a maximum of 60 seconds and
is only a reminder.
You have opened the driver's door with the engine switched off.
The KEYLESS-GO key is not in the ignition lock.
X Remember to take the KEYLESS-GO key with you when you
leave the vehicle. 00AF
Key Not Detected Key Not Detected
(red display message) The KEYLESS-GO key is not in the vehicle.
A warning tone also sounds.
If the engine is switched off, you can no longer lock the vehicle
centrally or start the engine.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 151).
X Locate the KEYLESS-GO key. The KEYLESS-GO key is not detected while the engine is running
because there is interference from a strong source of radio waves.
A warning tone also sounds.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 151).
X Operate the vehicle with the SmartKey in the ignition lock. 232
Display
messagesOn-board computer and displays