2016 MERCEDES-BENZ C CLASS key battery

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). X
To open the trunk lid automatically from
outside the vehicle: press and hold the T
button until the trunk lid opens. X
To open the trunk lid automatically from
outside the vehicle: if the SmartKey is loca-
ted in the immediate vicinity of the vehicle,
press the T button 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.
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
7 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 key determines whether a valid Smart-
Key is in, or in the direct vicinity of, the vehicle.
This occurs, for example: R
when starting the engine R
while driving R
when using HANDS-FREE ACCESS R
when the external door handles are touched R
during convenience closing X
To unlock the vehicle: touch the inner sur-
face of the door handle. X
To lock the vehicle: touch sensor surface C
or D .
Make sure that you do not touch the inner
surface of the door handle. X
Convenience closing feature: touch
recessed sensor surface D for an extended
period.
Further information on the convenience clos-
ing feature ( Y
page 96). X
To unlock the trunk lid: pull the handle on
the trunk lid.
Deactivating and activating If you do not intend to use a key 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. X
To deactivate: press the 7 button on the
SmartKey twice in rapid succession.
The battery check lamp of the SmartKey
flashes twice briefly and lights up once, then
KEYLESS-GO is deactivated ( Y
page 84).X
To activate: press any button on the Smart-
Key.
or X
Insert the SmartKey into the ignition lock.
KEYLESS-GO and all of its associated features
are available again.82
SmartKey
Opening and closing

KEYLESS- GO start function
Gene ra l notesBear in min d that th e engin e can be started by
any of th e vehicl e occupant s if there is a Smart -
Key in th e vehicle.
Changing the settings of the locking
system You can chang e th e setting s of th e locking sys-
tem. This mean s that only th e driver's door and
th e fuel filler flap are unlocke d when th e vehicl e
is unlocked. This is useful if you frequentl y travel
on your own .X
To change th e setting: press and hold down
th e 6 and 7 buttons simultaneousl y
for approximately six seconds until th e bat -
tery chec k lamp flashes twice ( Y
page 84).
If th e setting of th e locking system is changed
within th e signal range of th e vehicle, pressing
th e 7 or 6 button:R
locks or R
unlocks th e vehicl e
The SmartKey no w function s as follows :X
To unlock: press th e 6 butto n once .X
To unlock centrally: press th e 6 butto n
twice .X
To lock: press th e 7 button.
The KEYLESS-GO function s can be changed as
follows :X
To unlock th e driver's door : touch th e inner
surfac e of th e door handle on th e driver's
door .X
To unlock centrally: touch th e inner surfac e
of th e door handle on th e front-passenger
door or th e rear door .X
To lock centrally: touch th e outer sensor
surfac e on on e of th e door handles .X
To restor e th e factory settings: press and
hold th e 6 and 7 buttons simulta ne -
o
usl y for approximately six seconds until th e
battery chec k lamp flashes twice
( Y
page 84) . Mechanical key
Gene ra l notesIf th e vehicl e can no longer be locke d or
unlocke d wit h th e SmartKey or KEYLESS-GO ,
use th e mechanical key.
If you use th e mechanical ke y to unloc k and
open th e driver's door , th e anti-thef t alarm sys-
te m will be triggered . Switc h off th e alarm
( Y
page 79) .
If you unloc k th e vehicl e usin g th e mechanical
key, th e fuel filler flap will no t be unlocke d auto -
matically. X
To unlock th e fuel filler flap: insert th e
SmartKey int o th e ignition lock.
Removing the me chanical key
X
Push release catch C in th e direction of th e
arrow and at th e sam e time remove mechan -
ical ke y D from th e SmartKey.
Further information : R
Unlocking th e driver's door ( Y
page 89 )R
Locking th e vehicl e ( Y
page 89 )
Inserting the me chanical key X
Push mechanical ke y D completely int o th e
SmartKey until it engage s and release
catch C is bac k in it s basic position .SmartKey 83
Opening and closing Z

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