
Driving safety systems
Overview of driving safety systems
In this section, you will find information aboutthe following driving safety systems:
R ABS ( Anti-lock Braking System)
( Y page 68)
R BAS ( Brake Assist System) ( Y page 69)
R BAS PLUS ( Brake Assist System Plus)
( Y page 69)
R ESP ®
(E lectronic Stability Program)
( Y page 70)
R EBD ( Electronic Brake force Distribution)
( Y page 73)
R PRE-SAFE ®
Brake ( Y page 73)
Important safety notes
If you fail to adapt your driving style or if you
are inattentive, the driving safety systems can
neither reduce the risk of an accident nor
override the laws of physics. Driving safety
systems are merely aids designed to assist
driving. You are responsible for the distance
to the vehicle in front, for vehicle speed and
for braking in good time. Always adapt your
driving style to suit the prevailing road,
weather and traffic conditions and maintain a
safe distance from the vehicle in front. Drive
carefully.
The driving safety systems described only
work as effectively as possible when there is
adequate contact between the tires and the
road surface. Please pay special attention to
the notes on tires, recommended minimum
tire tread depths, etc. ( Y page 332).
In wintry driving conditions, always use winter
tires (M+S tires) and if necessary, snow
chains. Only in this way will the driving safety
systems described in this section work as
effectively as possible.
ABS (Anti-lock Braking System)
General information
ABS regulates brake pressure in such a way
that the wheels do not lock when you brake.
This allows you to continue steering the vehi- cle when braking.
The yellow ! ABS warning lamp in the
instrument cluster lights up when the ignition is switched on. It goes out when the engine is
running.
Important safety notes
iObserve the "Important safety notes" sec-
tion ( Y page 68).
GWARNING
If ABS is faulty, the wheels could lock when
braking. The steerability and braking charac-
teristics may be severely impaired. Addition-
ally, further driving safety systems are deac-
tivated. There is an increased danger of skid-
ding and accidents.
Drive on carefully. Have ABS checked imme-
diately at a qualified specialist workshop.
When ABS is malfunctioning, other systems,
including driving safety systems, will also
become inoperative. Observe the information on the ABS warning lamp ( Y page 262) and
display messages which may be shown in the
instrument cluster ( Y page 236).
ABS works from a speed of about 5 mph
(8 km/h), regardless of road-surface condi-
tions. ABS works on slippery surfaces, even if
you only brake gently.
Brakes
X If ABS intervenes: continue to depress the
brake pedal vigorously until the braking sit-
uation is over.
X To make a full brake application:
depress the brake pedal with full force.
If ABS intervenes when braking, you will feel a pulsing in the brake pedal.
68Driving safety systems
Safety

The pulsating brake pedal can be an indica-
tion of hazardous road conditions, and func-
tions as a reminder to take extra care while
driving.
BAS (Brake Assist System)
General information
BAS operates in emergency braking situa-
tions. If you depress the brake pedal quickly,
BAS automatically boosts the braking force,
thus shortening the stopping distance.
Important safety notes
iObserve the "Important safety notes" sec-
tion ( Y page 68).
GWARNING
If BAS is malfunctioning, the braking distance
in an emergency braking situation is
increased. There is a risk of an accident.
In an emergency braking situation, depress
the brake pedal with full force. ABS prevents
the wheels from locking.
Braking
X
Keep the brake pedal firmly depressed until
the emergency braking situation is over.
ABS prevents the wheels from locking.
The brakes will function as usual once you
release the brake pedal. BAS is deactivated.
BAS PLUS (Brake Assist System
PLUS)
General information
iObserve the "Important safety notes" sec-
tion ( Y page 68).
BAS PLUS is only available in vehicles equip-
ped with DISTRONIC PLUS.
For BAS PLUS to assist you, the radar sensor system must be operational. With the help of the radar sensor system, BAS
PLUS can detect obstacles that are in the
path of your vehicle for an extended period of
time.
If the radar sensor system is malfunctioning,
BAS PLUS will not be available. The brake
system is still available with complete brake
boosting effect and BAS.
BAS PLUS can help you to minimize the risk of a collision with a vehicle or reduce the effects
of such a collision. If BAS PLUS detects a
danger of collision, you are assisted when
braking.
Important safety notes
GWARNING
BAS PLUS cannot always clearly identify
objects and complex traffic situations.
In such cases, BAS PLUS may:
R intervene unnecessarily
R not intervene
There is a risk of an accident.
Always pay careful attention to the traffic sit- uation and be ready to brake. Terminate the
intervention in a non-critical driving situation.
GWARNING
BAS PLUS does not react:
R to people or animals
R to oncoming vehicles
R to crossing traffic
R when cornering
As a result, BAS PLUS may not intervene in all
critical situations. There is a risk of an acci-
dent.
Always pay careful attention to the traffic sit-
uation and be ready to brake.
In the event of snowfall or heavy rain, the rec-
ognition can be impaired.
Driving safety systems69
Safety
Z

Recognition by the radar sensor system is
also impaired in the event of:R there is dirt on the sensors or anything else
covering the sensors
R there is interference by other radar sources
R there are strong radar reflections, for
example in parking garages
R a narrow vehicle traveling in front, e.g. a
motorbike
R a vehicle traveling in front on a different line
relative to the center of your vehicle
Following damage to the front end of the vehi-
cle, have the configuration and operation of
the radar sensors checked at a qualified spe-
cialist workshop. This also applies to colli-
sions at low speeds where there is no visible
damage to the front of the vehicle.
Function
To avoid a collision, BAS PLUS calculates the
brake force necessary if:
R you approach an obstacle, and
R BAS PLUS has detected a risk of collision
When driving at a speed under 20 mph
(30 km/h) : if you depress the brake pedal,
BAS PLUS is activated. The increase in brake pressure will be carried out at the last possi-
ble moment.
When driving at a speed above 20 mph
(30 km/h) : if you depress the brake pedal
sharply, BAS PLUS automatically raises the
brake pressure to a value adapted to the traf-
fic situation.
BAS PLUS provides braking assistance in haz-
ardous situations with vehicles in front within a speed range between 4 mph (7 km/h) and
155 mph (250 km/h).
At speeds of up to approximately 40 mph
(70 km/h), BAS PLUS can also react to sta-
tionary objects. Examples of stationary
objects are stopped or parked vehicles.
iIf BAS PLUS demands particularly high
braking force, preventative passenger pro- tection measures (PRE-SAFE
®
) are activa-
ted simultaneously.
X Keep the brake pedal depressed until the
emergency braking situation is over.
ABS prevents the wheels from locking.
BAS PLUS is deactivated and the brakes func- tion as usual again, if:
R you release the brake pedal.
R there is no longer a risk of collision.
R no obstacle is detected in front of your
vehicle.
ESP® (Electronic Stability Program)
General notes
iObserve the "Important safety notes" sec-
tion ( Y page 68).
ESP ®
monitors driving stability and traction,
i.e. power transmission between the tires and the road surface.
If ESP ®
detects that the vehicle is deviating
from the direction desired by the driver, one
or more wheels are braked to stabilize the
vehicle. The engine output is also modified to keep the vehicle on the desired course within
physical limits. ESP ®
assists the driver when
pulling away on wet or slippery roads. ESP ®
can also stabilize the vehicle during braking.
ETS/4ETS (Electronic Traction System)
iObserve the "Important safety notes" sec-
tion ( Y page 68).
ETS traction control is part of ESP ®
. On vehi-
cles with 4MATIC, 4ETS is part of ESP ®
.
Traction control brakes the drive wheels indi-
vidually if they spin. This enables you to pull
away and accelerate on slippery surfaces, for example if the road surface is slippery on one
side. In addition, more drive torque is trans-
ferred to the wheel or wheels with traction.
Traction control remains active, even if you
deactivate ESP ®
.
70Driving safety systems
Safety

EBD (electronic brake force distribu-
tion)
General information
EBD monitors and controls the brake pres-
sure on the rear wheels to improve driving
stability while braking.
Important safety notes
iObserve the "Important safety notes" sec-
tion ( Y page 68).
GWARNING
If EBD is malfunctioning, the rear wheels can
lock, e.g. under full braking. This increases the
risk of skidding and an accident.
You should therefore adapt your driving style
to the different handling characteristics. Havethe brake system checked at a qualified spe-
cialist workshop.
Observe information regarding indicator and
warning lamps ( Y page 262) as well as dis-
play messages ( Y page 237).
PRE-SAFE® Brake
General information
iObserve the "Important safety notes" sec-
tion ( Y page 68).
PRE-SAFE ®
Brake is only available in vehicles
with DISTRONIC PLUS.
For PRE-SAFE ®
Brake to assist you when driv-
ing, the radar sensor system must be opera-
tional.
With the help of the radar sensor system,
PRE-SAFE ®
Brake can detect obstacles that
are in front of your vehicle for an extended
period of time.
PRE-SAFE ®
Brake can help you to minimize
the risk of a collision with a vehicle ahead, and reduce the effects of such a collision. If PRE-
SAFE ®
Brake has detected a risk of collision,
you will be warned visually and acoustically as well as by automatic braking. PRE-SAFE
®
Brake cannot prevent a collision without your
intervention.
Important safety notes
GWARNING
PRE-SAFE ®
Brake will initially brake your vehi-
cle by a partial application of the brakes if a
danger of collision is detected. There may be
a collision unless you also brake. Automatic
emergency braking cannot prevent a colli-
sion. There is a risk of an accident.
Always apply the brakes yourself and try to
take evasive action.
GWARNING
PRE-SAFE ®
Brake cannot always clearly iden-
tify objects and complex traffic conditions.
In these cases, PRE-SAFE ®
Brake may:
R give an unnecessary warning and then
brake the vehicle
R not give a warning or intervene
There is a risk of an accident.
Always pay particular attention to the traffic
situation and be ready to brake, especially if
PRE-SAFE ®
Brake warns you. Terminate the
intervention in a non-critical driving situation.
In order to maintain the appropriate distance
to the vehicle in front and thus prevent a col- lision, you must apply the brakes yourself.
GWARNING
PRE-SAFE ®
Brake does not react:
R to people or animals
R to oncoming vehicles
R to crossing traffic
R when cornering
As a result, PRE-SAFE ®
Brake may neither
give warnings nor intervene in all critical sit-
uations. There is a risk of an accident.
Always pay careful attention to the traffic sit-
uation and be ready to brake.
Driving safety systems73
Safety
Z

In the event of snowfall or heavy rain, the rec-
ognition can be impaired.
Recognition by the radar sensor system is
also impaired in the event of:
R there is dirt on the sensors or anything else
covering the sensors
R there is interference by other radar sources
R there are strong radar reflections, for
example in parking garages
R a narrow vehicle traveling in front, e.g. a
motorbike
R a vehicle traveling in front on a different line
relative to the center of your vehicle
Following damage to the front end of the vehi-
cle, have the configuration and operation of
the radar sensors checked at a qualified spe-
cialist workshop. This also applies to colli-
sions at low speeds where there is no visible
damage to the front of the vehicle.
Function
X To activate/deactivate: activate or deac-
tivate PRE-SAFE ®
Brake in the on-board
computer ( Y page 229).
If the PRE-SAFE ®
Brake is not activated, the
æ symbol appears in the multifunction
display.
Starting at a speed of around 4 mph (7 km/h),
this function warns you if you rapidly
approach a vehicle in front. An intermittent
warning tone will then sound and the ·
distance warning lamp will light up in the
instrument cluster.
X Brake immediately to defuse the situation.
or
X Take evasive action provided it is safe to do
so.
PRE-SAFE ®
Brake can also brake the vehicle
automatically under the following conditions: R the driver and front-passenger have their
seat belts fastened and
R the vehicle speed is between approx-
imately 4 mph (7 km/h) and 124 mph
(200 km/h)
At speeds of up to approximately 40 mph
(70 km/h) PRE-SAFE ®
Brake can also detect
stationary objects. Examples of stationary
objects are stopped or parked vehicles.
iIf there is an increased risk of collision,
preventive passenger protection measures
(PRE-SAFE ®
) are activated.
If the risk of collision with the vehicle in front
remains and you do not brake, take evasive
action or accelerate significantly, the vehicle
may perform automatic emergency braking,
up to the point of full brake application. Auto- matic emergency braking is not performed
until immediately prior to an imminent acci-
dent.
You can prevent the intervention of the PRE-
SAFE ®
Brake at any time by:
R depressing the accelerator pedal further.
R activating kickdown.
R releasing the brake pedal.
The braking action of PRE-SAFE ®
Brake is
ended automatically if:
R you maneuver to avoid the obstacle.
R there is no longer any danger of a collision.
R there is no longer an obstacle detected in
front of your vehicle.
Protection against theft
Immobilizer
The immobilizer prevents your vehicle from
being started without the correct SmartKey.
X To activate with the SmartKey: remove
the SmartKey from the ignition lock.
X To activate with KEYLESS-GO: switch the
ignition off and open the driver's door.
X To deactivate: switch on the ignition.
74Protection against theft
Safety

When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. The
engine can be started by anyone with a valid
SmartKey that is left inside the vehicle.
iThe immobilizer is always deactivated
when you start the engine.
In the event that the engine cannot be star-
ted (yet the vehicle's battery is charged),
the system 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)
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 tailgate
R the hood
The alarm is not switched off, even if you
close the open door that triggered it, for
example.
iIf the alarm continues for more than
30 seconds, the mbrace emergency call
system automatically notifies the Cus-
tomer Assistance Center. This is done
either by text message or data connection. The emergency call system sends the mes-sage 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.
XTo arm: lock the vehicle with the SmartKey
or KEYLESS-GO.
Indicator lamp : flashes. The alarm sys-
tem is armed after approximately
15 seconds.
X To deactivate: unlock the vehicle with the
SmartKey or KEYLESS-GO.
X To stop the alarm using the SmartKey:
insert the SmartKey into the ignition lock.
The alarm is switched off.
or X Press the % or & button on the
SmartKey.
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.
Protection against theft75
Safety
Z

Useful information
iThis 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.
iRead the information on qualified special-
ist workshops ( Y page 27).
SmartKey
Important safety notes
GWARNING
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.
GWARNING
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.
GWARNING
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 arisk 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.
R Do not keep the KEYLESS-GO key:
- with electronic devices, e.g. a mobile
phone or another SmartKey
- with metallic objects, e.g. coins or metal
foil
- inside metallic objects e.g. a metal case
This can affect the functionality of the
SmartKey.
SmartKey functions
The SmartKey centrally locks/unlocks:
R the doors
R the tailgate
R the fuel filler flap
:& To lock the vehicle
;F To open/close the tailgate
=% To unlock the vehicle
78SmartKey
Opening and closing

The turn signals flash once when unlocking
and three times when locking.
When it is dark, the surround lighting also
comes on if it is activated in the on-board
computer (Y page 231).
You can also set an audible signal to confirm that the vehicle has been locked. The audiblesignal can be activated and deactivated using
the on-board computer ( Y page 232).
X To unlock centrally: press the % but-
ton.
If you do not open the vehicle within approx-
imately 40 seconds of unlocking:
R the vehicle is locked again
R protection against theft is reactivated.
X To lock centrally: press 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 KEY-LESS-GO 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
functions of KEYLESS-GO with those of a con- ventional SmartKey. Unlock the vehicle by
using KEYLESS-GO, for instance, and lock it
using the & button on the SmartKey.
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). KEYLESS-GO checks whether a valid Smart-
Key is in the vehicle by periodically establish-
ing a radio connection between the vehicle
and the SmartKey. This happens:
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
surface of the door handle.
X To lock the vehicle: touch sensor sur-
face :.
X Convenience closing feature: touch
recessed sensor surface ; for an exten-
ded period.
Further information on the convenience clos-
ing feature ( Y page 94).
If you pull on the handle of the tailgate, only
the cargo compartment of the vehicle is
unlocked.
Deactivating and activating
If you do not intend to use the vehicle for a
longer period of time, you can deactivate KEY-
LESS-GO. The SmartKey will then use very lit-
tle power, thereby conserving battery power.
For the purposes of activation/deactivation,
the vehicle must not be nearby.
SmartKey79
Opening and closing
Z