key battery MERCEDES-BENZ C CLASS 2016 User Guide

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 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 X
Press the 7 or 6 button.
The battery is working properly if battery
check lamp C lights up briefly.
The battery is discharged if battery check
lamp C does not light up briefly. X
Change the battery ( Y
page 84).
If the SmartKey battery is checked within the
signal reception range of the vehicle, pressing
the 7 or 6 button: R
locks or R
unlocks the vehicle
i You can get a battery at any qualified spe-
cialist workshop.
Replacing the battery You require a CR 2025 3 V cell battery. X
Take the mechanical key out of the SmartKey
( Y
page 83).
X
Press mechanical key D into the SmartKey
opening in the direction of the arrow until bat-
tery compartment cover C opens. Do not
hold battery compartment cover C closed
while doing so. X
Remove battery compartment cover C .84
SmartKey
Opening and closing

X
Repeatedly tap th e SmartKey against your
palm until battery

Problems with the SmartKey Problem
Possible causes/consequences and P Solutions
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 necessary
( Y
page 84).
If this does not work: X
Unlock ( Y
page 89) 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 89) or lock ( Y
page 89) the vehicle using the
mechanical key.
The SmartKey is faulty. X
Unlock ( Y
page 89) 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 82).
The SmartKey battery is discharged or nearly discharged. X
Check the SmartKey battery ( Y
page 84) and replace it if necessary
( Y
page 84).
If this does not work: X
Unlock ( Y
page 89) 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 89) 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 con-
trol function: X
Unlock ( Y
page 89) or lock ( Y
page 89) the vehicle using the
mechanical key. X
Have the vehicle and SmartKey checked at a qualified specialist
workshop.86
SmartKey
Opening and closing

Problem
Possible causes/consequences and P Solutions
The engine cannot be
started using the Smart-
Key. 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 350).
or X
Jump-start the vehicle ( Y
page 352).
or X
Consult 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. 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 necessary
( 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 workshop. 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.
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. Doors 87
Opening and closing Z

Switching the seat ventilation on/off
The three blue indicator lamps in the buttons
indicate the ventilation level you have selected. X
Turn the SmartKey to position 1 or 2 in the
ignition lock ( Y
page 146).X
To switch on: press button C repeatedly
until the desired ventilation level is set. X
To switch off: press button C repeatedly
until all the indicator lamps go out.
i If the battery voltage is too low, the seat
ventilation may switch off.
i You can open the side windows and the slid-
ing sunroof using the "Convenience opening"
feature ( Y
page 96). The seat ventilation of
the driver's seat automatically switches to the
highest level.
i When the vehicle is stationary, the fan
speed can be reduced automatically. This
reduces the noises of the seat ventilation. Seats 109
Seats, steering wheel and mirrors Z

Problems with the seat heating or seat ventilation Problem
Possible causes/consequences and P Solutions
Seat heating or seat ven-
tilation has been
switched off prematurely
or cannot be switched
on. The on-board voltage is too low because too many electrical consum-
ers are switched on. X
Switch off electrical consumers that you do not need, such as the
rear window defroster or interior lighting.
Once the battery is sufficiently charged, the seat heating or seat
ventilation can be switched back on manually.
Steering wheel
Important safety notes
G WARNING
You could lose control of your vehicle if you do
the following while driving: R
adjust the driver's seat, head restraint,
steering wheel or mirrors R
fasten the seat belt
There is a risk of an accident.
Adjust the driver's seat, head restraint, steer-
ing wheel and mirror and fasten your seat belt
before starting the engine.
G WARNING
Children could injure themselves if they
adjust the steering wheel. There is a risk of
injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children unsupervised in the vehicle.
The electrically adjustable steering wheel can
still be adjusted when there is no key in the igni-
tion lock. Adjusting the steering wheel man-
ually
C
Release lever D
To adjust the steering wheel height

light switch to the ` position, the daytime
running lamps and parking lamps switch on.
If the engine is running and you turn the light
switch to the X position, the manual settings
take precedence over the daytime running
lamps.
USA only:
The daytime running lamps improve the visibility
of your vehicle during the day. To do this, the
daytime running lamps function must be
switched on using the on-board computer
( Y
page 250).
If the engine is running and you turn the light
switch to the ` or X position, the manual
settings take precedence over the daytime run-
ning lamps.
Low-beam headlamps Even if the light sensor does not detect that it is
dark, the parking lamps and low-beam head-
lamps switch on when the ignition is switched on
and the light switch is set to the X position.
This is a particularly useful function in the event
of rain and fog. X
To switch on the low-beam headlamps:
turn the SmartKey in the ignition lock to posi-
tion 2 or start the engine.X
Turn the light switch to the X position.
The green X indicator lamp in the instru-
ment cluster lights up.
Rear fog lamp The rear fog lamp improves visibility of your
vehicle for the traffic behind in the event of thick
fog. Please take note of the country-specific
regulations for the use of rear fog lamps. X
To switch on the rear fog lamp: turn the
SmartKey in the ignition lock to position 2 or
start the engine. X
Turn the light switch to the X or X
position. X
Press the ^ button.
The yellow ^ indicator lamp in the instru-
ment cluster lights up. X
To switch off the rear fog lamp: press the
^ button.
The yellow
^ in dicator lamp in the instru-
ment cluster goes out. Parking lamps
! If the battery has been excessively dis-
charged, the parking lamps or standing lamps
are automatically switched off to enable the
next engine start. Always park your vehicle
safely and sufficiently lit according to legal
standards. Avoid the continuous use of the
` parking lamps for several hours. If pos-
sible, switch on the d right or the c left
standing lamp. X
To switch on: turn the light switch to the
` position.
The green ` indicator lamp in the instru-
ment cluster lights up.
Standing lamps Switching on the standing lamps ensures the
corresponding side of the vehicle is illuminated. X
To switch on the standing lamps: the
SmartKey should not be in the ignition lock or
it should be in position 0 .X
Turn the light switch to the c (left-hand
side of the vehicle) or d ((right-hand side
of the vehicle) position.
Combination switch
C
High-beam headlamps
D
Turn signal, right

Control panel in the grab handle (rear
compartment)
C
Reading lampD
= To switch the reading lamp on/off
Interior lighting control
General notes In order to prevent the vehicle's battery from
discharging, the interior lighting functions are
automatically deactivated after some time
except when the SmartKey is in position 2 in the
ignition lock.
The color, brightness and display lighting for the
ambient lighting are set using the multimedia
system (see the separate operating instruc-
tions).
Automatic interior lighting control X
To switch on/off: press the 3 button.
When the automatic interior lighting control is
activated, the button is flush with the over-
head control panel.
The interior lighting automatically switches on if
you: R
unlock the vehicle R
open a door R
remove the SmartKey from the ignition lock
The interior light is activated for a short while
when the SmartKey is removed from the ignition
lock. This delayed switch-off can be adjusted via
the multimedia system (see the separate oper-
ating instructions). Replacing bulbs
Important safety notes
G WARNING
Bulbs, lamps and connectors can get very hot
when operating. If you change a bulb, you
could burn yourself on these components.
There is a risk of injury.
Allow these components to cool down before
changing a bulb.
Do not use a bulb that has been dropped or if its
glass tube has been scratched.
The bulb may explode if: R
you touch it R
it is hot R
you drop it R
you scratch it
Only operate bulbs in enclosed lamps designed
for that purpose. Only install spare bulbs of the
same type and the specified voltage.
Marks on the glass tube reduce the service life
of the bulbs. Do not touch the glass tube with
your bare hands. If necessary, clean the glass
tube when cold with alcohol or spirit and rub it
off with a lint-free cloth.
Protect bulbs from moisture during operation.
Do not allow bulbs to come into contact with
liquids.
Only replace the bulbs listed ( Y
page 123).
Have the bulbs that you cannot replace yourself
replaced at a qualified specialist workshop.
If you require assistance replacing bulbs, con-
sult a qualified specialist workshop.
If the new bulb still does not light up, consult a
qualified specialist workshop.
Headlamps and lights are an important aspect of
vehicle safety. You must therefore make sure
that these function correctly at all times. Have
the headlamp setting checked regularly.
Veh icles with LED headlamps: t he front and
rear light clusters of your vehicle are equipped
with LED light bulbs. Do not replace the bulbs
yourself. Contact a qualified specialist work-
shop which has the necessary specialist knowl-
edge and tools to carry out the work required.122
Replacing bulbs
Lights and windshield wipers

Defrosting th e windows
Windows fogged up on th e insideX
Activat e th e "Coolin g wit h air dehumidifica-
tion " function wit h th e Z rocker switch .X
Switc h on automatic mode usin g th e X
rocker switch .X
If th e windows continue to fo g up, activat e th e
"Windshield defrosting" function usin g th e
d rocker switch .
i You should only selec t this setting until th e
windshield is clear again .
Windows fogged up on th e outsid eX
Activat e th e windshield wipers .X
Switc h on automatic mode usin g th e X
rocker switch .
i If you clean th e windows regularly, they do
no t fo g up so quickly.
Rea r window defroster
General notes The rea r window defroster has a hig h curren t
draw. You should therefore switch it of f as soo n
as th e rea r window is clear . Otherwise , th e rea r
window defroster switches of f automatically
after severa l minutes.
If th e battery voltage is to o low, th e rea r window
defroster may switch off.
Switchin g on/of fX
Tur n th e SmartKey to position 2 in th e ignition
loc k ( Y
page 146).X
Press th e l rocker switch up or down .
The indicator lamp abov e th e l rocker
switch lights up or goe s out .136
Operating the climate control systems
Climate control

Problems with the rear window defroster Problem
Possible causes/consequences and P Solutions
The rear window
defroster has deactiva-
ted prematurely or can-
not be activated. The battery has not been sufficiently charged. X
Switch off any consumers that are not required, e.g. reading lamps,
interior lighting or the seat heating.
When the battery is sufficiently charged, the rear window defroster
can be activated again.
Switching air-recirculation mode
on/off
General notes You can also temporarily deactivate the flow of
fresh air manually if unpleasant odors are enter-
ing the vehicle from outside. The air already
inside the vehicle will then be recirculated.
If you switch on air-recirculation mode, the win-
dows can fog up more quickly, in particular at
low temperatures. Only use air-recirculation
mode briefly to prevent the windows from fog-
ging up.
Switching on/off X
Turn the SmartKey to position 2 in the ignition
lock ( Y
page 146).X
To activate: press the r rocker switch up
or down.
The indicator lamp above the r rocker
switch lights up.
Air-recirculation mode switches on automati-
cally: R
at high outside temperatures R
at high levels of pollution (3-zone automatic
climate control only) R
in a tunnel (vehicles with a navigation system
only)
The indicator lamp above the r rocker
switch is not lit when automatic air-recirculation
mode is activated. Outside air is added after
about 30 minutes. X
To deactivate: press the r rocker switch
up or down.
The indicator lamp above the r rocker
switch goes out. Air-recirculation mode deactivates automati-
cally: R
after approximately five minutes at outside
temperatures below approximately 41 ‡
(5 †) R
after approximately five minutes if cooling
with air dehumidification is deactivated R
after approximately 30 minutes at outside
temperatures above approximately 41 ‡
(5 †) if the "Cooling with air dehumidifica-
tion" function is activated
Switching the residual heat on or off
General notes The residual heat function is only available with
3-zone automatic climate control on vehicles for
Canada.
Once the engine is switched off, it is possible to
make use of the residual heat of the engine to
continue heating or ventilating the front com-
partment of the vehicle for approximately
30 minutes. The heating or ventilation time
depends on the interior temperature that has
been set.
Switching on/off X
Turn the SmartKey to position 0 in the ignition
lock or remove it ( Y
page 146).X
To switch on: press the ! rocker switch
up or down.
The indicator lamp above the ! rocker
switch lights up.
The blower will run at a low speed regardless of
the airflow setting.
If you activate the residual heat function at high
temperatures, only the ventilation will be acti-
vated. The blower runs at medium speed.Operating the climate control systems 137
Climate control