2017 MERCEDES-BENZ S CLASS key

of the child restraint system must always rest on
the seat cushion of the front-passenger seat.
The backrest of the child restraint system must
lie as flat as possible against the backrest of the
front-passenger seat. The child restraint system
must not touch the roof or be subjected to a load
by the head restraint. Adjust the angle of the
seat backrest and the head restraint position
accordingly. Always make sure that the shoul-
der belt strap is correctly routed from the vehi-
cle belt outlet to the shoulder belt guide on the
child restraint system. The shoulder belt strap
must be routed forwards and downwards from
the vehicle belt outlet. If necessary, adjust the
vehicle belt outlet and the front-passenger seat
accordingly.
Always observe the child restraint system man-
ufacturer's installation and operating instruc-
tions.
Child-proof locks
Important safety notes
G WARNING
If children are traveling in the vehicle, they
could: R
open doors, thus endangering other people
or road users R
exit the vehicle and be caught by oncoming
traffic R
operate vehicle equipment and become
trapped
There is a risk of an accident and injury.
Always activate the child-proof locks and
override feature if children are traveling in the
vehicle. When leaving the vehicle, always take
the key with you and lock the vehicle. Never
leave children unattended in the vehicle.
Override feature for: R
the rear doors ( Y
page 65)R
the rear side windows ( Y
page 65) G WARNING
If you leave children unsupervised in the vehi-
cle, they could set it in motion by, for example: R
release the parking brake. R
shift the automatic transmission out of the
parking position P .R
start the engine.
In addition, they may operate vehicle equip-
ment and become trapped. 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 unsupervised in the vehicle.
G WARNING
If persons, particularly children are subjected
to prolonged exposure to extreme heat or
cold, there is a risk of injury, possibly even
fatal. Never leave children unattended in the
vehicle.
G WARNING
If the child restraint system is subjected to
direct sunlight, parts may get very hot. Chil-
dren may burn themselves on these parts,
particularly on the metal parts of the child
restraint system. There is a risk of injury.
If you leave the vehicle, taking the child with
you, always ensure that the child restraint
system is not exposed to direct sunlight. Pro-
tect it with a blanket, for example. If the child
restraint system has been exposed to direct
sunlight, let it cool down before securing the
child in it. Never leave children unattended in
the vehicle.64
Children in the vehicle
Safety

i The immobilizer is always deactivated when
you start the engine.
In the event that the engine cannot be started
(yet the vehicle's battery is charged), the sys-
tem is not operational. Contact an authorized
Mercedes-Benz Center or call
1-800-FOR-MERCedes (in the USA) or
1-800-387-0100 (in Canada).
ATA (anti-theft alarm system) X
To arm: lock the vehicle with the SmartKey or
KEYLESS-GO.
Indicator lamp C flashes. The alarm system
is armed after approximately ten seconds. X
To disarm: unlock the vehicle with the Smart-
Key or KEYLESS-GO.
or X
Insert the SmartKey into the ignition lock.
or X
Press the Start/Stop button.
The SmartKey must be in the vehicle.
A visual and audible alarm is triggered if the
alarm system is armed and you open: R
a door R
the vehicle with the mechanical key R
the trunk lid R
the hood X
To stop the alarm with the SmartKey:
press the 6 or 7 button on the Smart-
Key.
The alarm is stopped.
or X
Remove the Start/Stop button from the igni-
tion lock. X
Insert the SmartKey into the ignition lock.
The alarm is stopped. X
To stop the alarm using KEYLESS-GO:
grasp the outside door handle. The SmartKey
must be outside the vehicle.
The alarm is stopped.
or X
Press the Start/Stop button on the dash-
board. The SmartKey must be inside the vehi-
cle.
The alarm is stopped.
The alarm is not switched off, even if you close
the open door that triggered it, for example.
i If the alarm continues for more than
30 seconds, the mbrace emergency call sys-
tem automatically notifies the Customer
Assistance Center. This is done either by text
message or data connection.
The emergency call system sends a message
or establishes a data connection provided
that: R
you have subscribed to the mbrace service. R
the mbrace service has been activated
properly. R
the necessary mobile phone network is
available.76
Protection against theft
Safety

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 PR
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 mag-
netic fields. Otherwise, the remote control
function could be affected.
Strong magnetic fields can occur in the vicin-
ity 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 Smart-
Key. Do not keep the SmartKey in the temperature-
controlled cup holder ( Y
page 292). On vehicles
with the KEYLESS-GO start function, do not
keep it on the parcel shelf or in the trunk. Oth-
erwise, the SmartKey may not be detected, e.g.
when starting the engine using the Start/Stop
button.
A brief radio connection between the vehicle
and the SmartKey determines whether a valid
SmartKey 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
SmartKey functions
C
7 Locks the vehicleD
T Opens/closes the trunk lid

signal can be activated and deactivated via the
multimedia system; see the Digital Operator's
Manual.
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 ( Y
page 147).
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 SmartKey determines whether a valid
SmartKey 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 92). X
To unlock the trunk lid: pull the handle on
the trunk lid.
Deactivating and activating If you do not intend to use a SmartKey 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 ( Y
page 80) of the
SmartKey flashes twice briefly and lights up
once, then KEYLESS-GO is deactivated. 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.78
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 vehicl e ( Y
page 147).
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 ( Y
page 80 ) flashes twice .
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 simu ltane -
o
usl y for approximately six seconds until th e
battery chec k lamp ( Y
page 80) flashes
twice . 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 76) .
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.
Fo r further information about :R
Locking/unlocking th e driver's door
( Y
page 84 ) R
Unlocking th e trunk ( Y
page 90 )
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 79
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 80).
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 obtain a battery from any qualified
specialist workshop.
Replacing the battery You require a CR 2025 3 V cell battery. X
Take the mechanical key out of the SmartKey
( Y
page 79).
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 .80
SmartKey
Opening and closing

X
Repeatedly tap th e SmartKey against your
palm until battery

Problem
Possible causes/consequences and P Solutions
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
Lock or unlock the vehicle using the mechanical key ( Y
page 84).X
Have the vehicle and SmartKey checked at a qualified specialist
workshop.
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 334).
or X
Jump-start the vehicle ( Y
page 335).
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 80) and replace it if necessary
( Y
page 80).
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.82
SmartKey
Opening and closing