
High-voltage battery
G
WARNING
In the event of a vehicle fire, the internal pres- sure of the high-voltage battery can exceed a
critical value. In this case flammable gas
escapes through a ventilation valve on the
underbody. The gas can ignite. There is a risk of injury.
Leave the danger zone immediately. Secure
the danger area at a suitable distance, whilst
observing legal requirements. G
WARNING
If the housing of the high-voltage battery has
been damaged, electrolyte and gases may
leak out. These are poisonous and caustic.
There is a risk of injury.
Avoid contact with skin, eyes or clothing.
Immediately rinse electrolyte splashes off
with water and seek medical attention
straight away.
! Exhaustive discharge caused by the vehi-
cle standing idle for lengthy periods can
damage the high-voltage battery.
Hybrid vehicles: if the vehicle is idle for
lengthy periods, run it for a few minutes
once every six weeks to charge up the high- voltage battery. During the charging proc-
ess, switch off all electrical consumers, e.g.
the automatic climate control or the seat
heating.
Plug-in hybrid vehicles: if the vehicle is
idle for lengthy periods leave the high-volt- age battery connected to a charging sta-
tion.
PLUG-IN HYBRID vehicles: charging the high-
voltage battery (Y page 209).
Engine compartment Before opening the hood:
X Apply the electric parking brake.
X Shift the automatic transmission to park
position P. X
Switch the ignition off.
X Remove the Start/Stop button from the
ignition lock (Y page 189).
or X If the SmartKey is inserted in the ignition
lock: remove the SmartKey from the igni-
tion lock.
X Observe the warning notes on the risk of
electric shock (Y page 46).
X Observe the warning notices about the
hood (Y page 404). RBS driving safety system (Recupera-
tive Brake System)
The Recuperative Braking System supports
you when braking with an electronically-con-
trolled brake boost mode and enables the
recovery of kinetic energy (recuperation). G
WARNING
If the Recuperative Braking System malfunc-
tions, braking resistance may be reduced and brake pedal travel may be longer than usual. If
you subsequently depress the brake pedal as usual, the braking effect may not be sufficient.
There is a risk of an accident.
In the event of this malfunction, continue to
depress the brake pedal. Stop the vehicle in
accordance with the traffic conditions. If nec-
essary, contact a qualified specialist work-
shop.
Further information about the Recuperative
Braking System (Y page 276).48
Hybrid vehiclesSafety

Panic alarm
X
To activate: press!button :for at
least one second.
An alarm sounds and the exterior lighting
flashes.
X To deactivate: press!button :
again.
or
X Press the Start/Stop button.
The SmartKey must be in the vehicle. Occupant safety
Restraint system: introduction
The restraint system reduces the risk of vehi-
cle occupants coming into contact with parts of the vehicle's interior in the event of an
accident. The restraint system can also
reduce the forces to which vehicle occupants
are subjected during an accident.
The restraint system comprises:
R Seat belt system
R Air bags
R Child restraint system
R Child seat securing systems The components of the restraint system work
in conjunction with each other. They can only deploy their protective function if, at all times,
all vehicle occupants:
R have fastened their seat belts correctly
(Y page 53)
R have adjusted their seat and head restraint
properly (Y page 121).
As the driver, you also have to make sure that
the steering wheel is adjusted correctly.
Observe the information relating to the cor-
rect driver's seat position (Y page 120).
You also have to make sure that an air bag can inflate properly if deployed (Y page 56).
An air bag supplements a correctly worn seat
belt. As an additional safety device, the air
bag increases the level of protection for vehi-
cle occupants in the event of an accident. For example, if, in the event of an accident, the
protection offered by the seat belt is suffi-
cient, the air bags are not deployed. When an
accident occurs, only the air bags that
increase protection in that particular accident
situation are deployed. However, seat belts
and air bags generally do not protect against objects penetrating the vehicle from the out-
side.
Information on restraint system operation
can be found under "Deployment of Emer-
gency Tensioning Devices and air bags"
(Y page 65).
For more information about children traveling
with you in the vehicle and on child restraint
systems, see "Children in the vehicle"
(Y page 69). Important safety notes
G
WARNING
Modifications to the restraint system may
cause it to no longer work as intended. The
restraint system may then not perform its
intended protective function and may fail in an accident or trigger unexpectedly, for example. Occupant safety
49Safety
Z

the child restraint system. Never place
objects under or behind the child restraint
system, e.g. cushions. Fully retract the seat
cushion length. The entire base of the child
restraint system must always rest on the seat cushion of the front-passenger seat. The
backrest of the forwards-facing child restraint
system must, as far as possible, be resting on the backrest of the front-passenger seat.
The child restraint system must not touch the
roof or be put under strain by the head
restraint. Adjust the angle of the seat back-
rest and the head restraint position accord-
ingly.
Only then can OCS be guaranteed to function correctly. Always observe the child restraint
system manufacturer's installation instruc-
tions.
Occupant Classification System opera-
tion (OCS) :
PASSENGER AIR BAG OFF indicator lamp
; PASSENGER AIR BAG ON indicator lamp
The indicator lamps inform you whether the
front-passenger front air bag is deactivated or
enabled.
X Press the Start/Stop button once or twice,
or turn the SmartKey to position 1or 2in
the ignition lock.
The system carries out self-diagnostics.
The PASSENGER AIR BAG OFF and
PASSENGER AIR BAG ON indicator lamps
must light up simultaneously for approx-
imately six second s. The indi
cator lamps display the status of the
front-passenger front air bag.
R PASSENGER AIR BAG OFF :lights up: the
front-passenger front air bag is deactiva-
ted. It will then not be deployed in the event
of an accident.
R PASSENGER AIR BAG ON ;lights up: the
front-passenger front air bag is enabled. If, in the event of an accident, all deployment
criteria are met, the front-passenger front
air bag is deployed.
If the status of the front-passenger front air
bag changes while the vehicle is in motion, an air bag display message appears in the instru-
ment cluster (Y page 332). When the front-
passenger seat is occupied, always pay atten-
tion to the PASSENGER AIR BAG ON and
PASSENGER AIR BAG OFF indicator lamps. Be aware of the status of the front-passenger
front air bag both before and during the jour- ney. G
WARNING
If the PASSENGER AIR BAG OFF indicator
lamp is lit, the front-passenger front air bag is disabled. It will not be deployed in the event of
an accident and cannot perform its intended
protective function. A person in the front-
passenger seat could then, for example, come
into contact with the vehicle's interior, espe-
cially if the person is sitting too close to the
dashboard. This poses an increased risk of
injury or even fatal injury.
When the front-passenger seat is occupied,
always ensure that:
R the classification of the person in the front-
passenger seat is correct and the front-
passenger front air bag is enabled or disa-
bled in accordance with the person in the
front-passenger seat
R the front-passenger seat has been moved
back as far back as possible.
R the person is seated correctly.
Make sure, both before and during the jour-
ney, that the status of the front-passenger
front air bag is correct. 60
Occupant safetySafety

X
To turn the alarm off with the SmartKey:
press the %or& button on the
SmartKey.
The alarm is switched off.
or
X Remove the Start/Stop button from the
ignition lock.
X Insert the SmartKey into the ignition lock.
The alarm is switched off.
X To stop the alarm using KEYLESS-GO:
grasp the outside door handle. The Smart-
Key must be outside the vehicle.
The alarm is switched off.
or
X Press the Start/Stop button on the dash-
board. The SmartKey must be inside the
vehicle.
The alarm is switched off.
The alarm is not switched off, even if you
close the open door that triggered it, for
example.
i If the alarm stays on for more than
30 second s,the mbrace emergency call
system automatically sends a message to
the Customer Assistance Center. This is
done either by text message or data con-
nection. The emergency call system sends
the message or data provided that:
R you have subscribed to the mbrace ser-
vice.
R the mbrace service has been activated
properly.
R the necessary mobile phone network is
available. Protection against theft
87Safety Z

Useful information
i This Operator's Manual describes all
models and all standard and optional equip- ment of your vehicle available at the time of
publication of the Operator's Manual.
Country-specific differences are possible.
Please note that your vehicle may not be
equipped with all features described. This
also applies to safety-related systems and
functions.
i Read the information on qualified special-
ist workshops (Y page 29). 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 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. 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
magnetic fields. Otherwise, the remote
control function could be affected.
Strong magnetic fields can occur in the
vicinity 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
SmartKey.
Do not keep the SmartKey in the tempera-
ture-controlled cup holder (Y page 380). On
vehicles with the KEYLESS-GO start function,
do not keep it on the parcel shelf or in the
trunk. Otherwise, the SmartKey may not be
detected, e.g. when starting the engine using the Start/Stop button.
A check which periodically establishes a radio
connection between the vehicle and the
SmartKey determines whether a valid Smart- Key is in the vehicle. This occurs, for example:
R when starting the engine
R whilst driving
R when using HANDS-FREE ACCESS
R when the external door handles are
touched
R during convenience closing 90
SmartKeyOpening and closing

Problem
Possible causes/consequences and
M
MSolutions The engine cannot be
started using the
SmartKey. 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 430).
or
X Jump-start the vehicle (Y page 432).
or
X Consult a qualified specialist workshop. The engine cannot be
started using the Start/
Stop button. The
SmartKey is in the vehi-
cle. 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 94) and replace it if nec-
essary (Y page 94).
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 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. 96
SmartKeyOpening and closing

!
The trunk lid swings upwards when
opened. Therefore, make sure that there is sufficient clearance above the trunk lid.
i The opening dimensions of the trunk lid
can be found in the "Vehicle data" section
(Y page 495).
Opening You can open the trunk lid automatically
using the SmartKey or the handle in the trunk
lid.
X Press and hold the Fbutton on the
SmartKey until the trunk lid opens.
or
X If the trunk lid is unlocked, pull the trunk lid
handle and let it go again immediately.
Closing You can close the trunk lid automatically
using the SmartKey or the closing button in
the trunk lid. X
Press and release closing button :on the
trunk lid.
or X If the SmartKey is located in the immediate
vicinity of the vehicle: press the Fbut-
ton on the SmartKey.
You can release the button as soon as the
trunk lid starts to close.
X To stop the closing process:
R Press the Fbutton on the SmartKey,
or
R Pull the trunk lid handle, or R
Press closing button :or locking but-
ton ;on the trunk lid, or
R Press the remote operating switch on the
driver's door, or
R In vehicles with HANDS-FREE ACCESS:
kick into the sensor detection range
under the bumper with your foot.
i If the
F button on the SmartKey is
pressed or HANDS-FREE ACCESS is initi-
ated after the closing process is stopped,
the trunk lid opens.
Vehicles with trunk lid remote closing
feature and KEYLESS-GO: when all the
doors are closed, you can simultaneously
close the trunk lid and lock the vehicle. The
key must be located to the rear of the vehicle.
X Press and release locking button ;on the
trunk lid.
If a KEYLESS-GO key is detected outside
the vehicle, the trunk lid closes and the
vehicle locks.
i If KEYLESS-GO detects a SmartKey in the
trunk, the trunk lid opens again after it is
closed.
If KEYLESS-GO detects a second SmartKey outside the vehicle, the trunk lid remains
closed. HANDS-FREE ACCESS
Important safety notes G
WARNING
The vehicle's exhaust system may be very hot. You could burn yourself by touching the
exhaust system if you use HANDS-FREE
ACCESS. There is a risk of injury. Always
ensure that you only make the kicking move-
ment within the detection range of sensors. 102
TrunkOpening and closing

:
Front left
; Front right
= Rear right
? Rear left
X Turn the SmartKey to position 1or 2in the
ignition lock (Y page 189).
X To open manually: press and hold the cor-
responding switch.
X To open fully: press the switch beyond the
point of resistance and release it.
Automatic operation is started.
X To close manually: pull and hold the cor-
responding switch.
X To close fully: pull the corresponding
switch beyond the pressure point.
Automatic operation is started.
X To interrupt automatic operation:
press/pull the corresponding switch again.
i If you press the switch beyond the point of
resistance and release, automatic opera-
tion is started in the corresponding direc-
tion. You can stop automatic operation by
pressing/pulling the switch again.
i You can continue to operate the side win-
dows after you switch off the engine or
remove the SmartKey. This function
remains active for five minutes or until you
open a front door.
i When the override feature for the side
windows is activated (Y page 75), the side
windows cannot be operated from the rear. i
Before opening or closing the side win-
dows, a check is carried out to see whether a valid SmartKey is in the vehicle, if:
R a side window switch is pressed or pulled
and
R the Start/Stop button is used instead of
the SmartKey in the ignition lock
and
R the engine is not running
This is carried out by means of a brief radio connection between the vehicle and the
SmartKey.
i Information on opening and closing the
roller sunblinds on the rear side windows
(Y page 381). Convenience opening
General notes You can ventilate the vehicle before you start
driving.
If the SmartKey is in close proximity to the
vehicle, the convenience opening function is
available.
To do this, the SmartKey is used to carry out
the following functions simultaneously:
R unlock the vehicle
R open the side windows
R open the panorama roof with power tilt/
sliding panel and the roller sunblinds
R switch on the seat ventilation for the driv-
er's seat
Convenience opening X
Press and hold the %button until the
side windows and the panorama roof with Side windows
107Opening and closing Z