2018 MERCEDES-BENZ CLS Key open

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.
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 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 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 sur-
face of the door handle. X
To lock the vehicle: touch sensor sur-
face C .X
Convenience closing feature: touch
recessed sensor surface D for an extended
period.
Further information on the convenience clos-
ing feature ( Y
page 88).X
To unlock the trunk lid: pull the handle on
the trunk lid.
The vehicle only unlocks 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 of the SmartKey
( Y
page 79) 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.
Changing the settings of the locking
system You can change the settings of the locking sys-
tem. 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 frequently travel
alone. X
To change the setting: press and hold down
the 6 and 7 buttons simultaneously
for approximately six seconds until the bat-
tery check lamp ( Y
page 79) flashes twice.
If the setting of the locking system is changed
within the signal range of the vehicle, pressing
the 7 or 6 button: R
locks or R
unlocks the vehicle
The SmartKey now functions as follows: X
To unlock: press the 6 button once.X
To unlock centrally: press the 6 button
twice. X
To lock centrally: press the 7 button.
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 surface
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 the 6 and 7 buttons simultane-
ou
sly fo r approximately six seconds until theSmartKey 77
Opening and closing Z

battery check lamp ( Y
page 79) flashes
twice.
Mechanical key
General notes If the vehicle can no longer be locked or
unlocked with the SmartKey, use the mechani-
cal 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. Switch off
the alarm ( Y
page 75).
If you unlock the vehicle using the mechanical
key, the fuel filler flap will not be unlocked auto-
matically. X
To unlock the fuel filler flap: insert the
SmartKey into the ignition lock.
Removing the mechanical key
X
Push release catch C in the direction of the
arrow and at the same time remove mechan-
ical key D from the SmartKey.
For further information about: R
unlocking the driver's door ( Y
page 83)R
unlocking the trunk ( Y
page 86)R
locking the vehicle ( Y
page 83)
Inserting the mechanical key X
Push mechanical key D completely into the
SmartKey until it engages and release
catch C is 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 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.78
SmartKey
Opening and closing

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 79).
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 78). 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 .
X
Repeatedly tap the 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 79) and replace it if necessary
( Y
page 79).
If this does not work: X
Unlock ( Y
page 83) or lock ( Y
page 83) the vehicle using the
mechanical key.
There is interference from a powerful source of radio waves. X
Unlock ( Y
page 83) or lock ( Y
page 83) the vehicle using the
mechanical key.
The SmartKey is faulty. X
Unlock ( Y
page 83) or lock ( Y
page 83) 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 76).
The SmartKey battery is discharged or nearly discharged. X
Check the SmartKey battery ( Y
page 79) and replace it if necessary
( Y
page 79).
If this does not work: X
Unlock ( Y
page 83) or lock ( Y
page 83) the vehicle using the
mechanical key.
There is interference from a powerful source of radio waves. X
Unlock ( Y
page 83) or lock ( Y
page 83) 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 83) or lock ( Y
page 83) the vehicle using the
mechanical key. X
Have the vehicle and SmartKey checked at a qualified specialist
workshop.80
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 284).
or X
Jump-start the vehicle ( Y
page 285).
or X
Consult a qualified specialist workshop.
The engine cannot be
started using KEYLESS-
GO. The SmartKey is in
the vehicle. The vehicle is locked. X
Unlock the vehicle and try to start the vehicle again.
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 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.
Unlocking and opening doors from
the inside You can open a door from inside the vehicle
even if it has been locked.
If the vehicle has previously been locked from
the outside, opening a door from the inside will
trigger the anti-theft alarm system. Switch off
the alarm ( Y
page 75).
You can only open the rear doors from inside the
vehicle if they are not secured by the child-proof
locks ( Y
page 63). Doors 81
Opening and closing Z

Locking/unlocking the driver's door
with the mechanical key
i If you want to centrally lock the vehicle using
the mechanical key, begin by pressing the
locking button for the interior locking mech-
anism while the driver's door is open. Then
lock the driver's door using the mechanical
key.
X
To unlock: turn the mechanical key counter-
clockwise as far as it will go to position G .X
To lock: turn the mechanical key clockwise as
far as it will go to position G .
If you use the mechanical key to unlock and
open the driver's door, the anti-theft alarm sys-
tem will be triggered. Switch off the alarm
( Y
page 75).
Trunk
Important safety notes
G WARNING
Combustion engines emit poisonous exhaust
gases such as carbon monoxide. Exhaust
gases can enter the vehicle interior if the
trunk lid is open when the engine is running,
especially if the vehicle is in motion. There is a
risk of poisoning.
Always switch off the engine before opening
the trunk lid. Never drive with the trunk lid
open.
G WARNING
If objects, luggage or loads are not secured or
not secured sufficiently, they could slip, tip
over or be flung around and thereby hit vehicle occupants. There is a risk of injury, particu-
larly in the event of sudden braking or a sud-
den change in direction.
Always store objects so that they cannot be
flung around. Secure objects, luggage or
loads against slipping or tipping before the
journey.
! The trunk lid swings upwards when opened.
Therefore, make sure that there is sufficient
clearance above the trunk lid.
The opening dimensions of the trunk lid can be
found in the "Vehicle data" section
( Y
page 328).
You should preferably place luggage or loads in
the trunk. Observe the loading guidelines
( Y
page 242).
Do not leave the SmartKey in the trunk. You
could otherwise lock yourself out.
Vehicles without the trunk lid remote clos-
ing feature: the trunk lid can be: R
opened and closed manually from outside R
opened automatically from outside R
opened automatically from inside R
locked separately R
opened with the emergency release button R
unlocked with the mechanical key
Vehicles with the trunk lid remote closing
feature: the trunk lid can be: R
opened and closed manually from outside R
opened/closed automatically from outside R
opened/closed automatically from inside R
locked separately R
opened with the emergency release button R
unlocked with the mechanical key
Trunk lid reversing feature The trunk lid is equipped with an automatic
reversing feature. It reacts if a solid object
obstructs or restricts the trunk lid during the
closing procedure. The trunk lid opens again
automatically. The automatic reversing feature
is only an aid and is not a substitute for your
attentiveness when closing the trunk. Trunk 83
Opening and closing Z

G WARNING
The reversing feature does not respond: R
to soft, light and thin objects, e.g. fingers R
over the last 1/3 in (8 mm) of the closing
movement
The reversing feature cannot prevent some-
one being trapped in these situations in par-
ticular. There is a risk of injury.
Make sure that no body parts are in close
proximity during the closing procedure.
If somebody becomes trapped: R
press the T button on the SmartKey, orR
pull or press the remote operating switch
on the driver's door or R
press the closing or locking button on the
trunk lid, or R
pull on the trunk lid handle
Opening/closing from outside
Opening
X
Press the 6 button on the SmartKey.X
Pull handle C .X
Raise the trunk lid. Closing X
Pull the trunk lid down using recess C .X
If necessary, lock the vehicle with the 7
button on the SmartKey ( Y
page 76) or with
KEYLESS-GO ( Y
page 76).
If KEYLESS-GO detects only one SmartKey in the
trunk after it closed, the trunk lid opens again. If
KEYLESS-GO detects a second SmartKey out-
side the vehicle, the trunk lid remains closed.
Opening/closing automatically from
outside
Important safety notes
G WARNING
Parts of the body could become trapped dur-
ing automatic closing of the trunk lid. More-
over, people, e.g. children, may be standing in
the closing area or may enter the closing area
during the closing process. There is a risk of
injury.
Make sure that nobody is in the vicinity of the
closing area during the closing process.
Use one of the following options to stop the
closing process: R
press the T button on the SmartKey. R
pull or press the remote operating switch
on the driver's door. R
press the closing or locking button on the
trunk lid. R
pull the trunk lid handle84
Trunk
Opening and closing

G WARNING
Combustion engines emit poisonous exhaust
gases such as carbon monoxide. Exhaust
gases can enter the vehicle interior if the
trunk lid is open when the engine is running,
especially if the vehicle is in motion. There is a
risk of poisoning.
Always switch off the engine before opening
the trunk lid. Never drive with the trunk lid
open.
! The trunk lid swings upwards when opened.
Therefore, make sure that there is sufficient
clearance above the trunk lid.
The opening dimensions of the trunk lid can be
found in the "Vehicle data" section
( Y
page 328).
Opening You can open the trunk lid automatically using
the SmartKey or the handle in the trunk lid. X
Press and hold the T button on the Smart-
Key until the trunk lid opens.
or X
If the trunk is unlocked, pull the trunk lid han-
dle and release it again immediately
( Y
page 84).
Closing
X
Press closing button C in the trunk lid.
Vehicles with trunk lid remote closing fea-
ture: you can simultaneously close the trunk lid
and lock the vehicle. The KEYLESS-GO key must
be in the rear detection range of the vehicle. X
Press locking button D in the trunk lid.
If all the doors are closed, the vehicle locks. If KEYLESS-GO detects only one SmartKey in the
trunk after it closed, the trunk lid opens again. If
KEYLESS-GO detects a second SmartKey out-
side the vehicle, the trunk lid remains closed.
Opening/closing automatically from
inside
Important safety notes
G WARNING
Parts of the body could become trapped dur-
ing automatic closing of the trunk lid. In addi-
tion, people may be standing in the closing
area or may enter the closing area, e.g. chil-
dren, during the closing procedure. There is a
risk of injury.
Make sure that nobody is in the vicinity of the
closing area during the closing process.
Release the remote operating switch imme-
diately if somebody becomes trapped. To re-
open the trunk lid, pull on the remote operat-
ing switch.
G WARNING
The trunk lid can be automatically opened or
closed even if the SmartKey is not in the vehi-
cle. If children are left unsupervised in the
vehicle, they could activate the functions.
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.
G WARNING
Combustion engines emit poisonous exhaust
gases such as carbon monoxide. Exhaust
gases can enter the vehicle interior if the
trunk lid is open when the engine is running,
especially if the vehicle is in motion. There is a
risk of poisoning.
Always switch off the engine before opening
the trunk lid. Never drive with the trunk lid
open. Trunk 85
Opening and closing Z