
COLLISION PREVENTION ASSIST
PLUS
General information COLLISION PREVENTION ASSIST PLUS consists
of a distance warning function with an autono-
mous braking function and adaptive Brake
Assist.
COLLISION PREVENTION ASSIST PLUS can help
you to minimize the risk of a front-end collision
with a vehicle ahead or reduce the effects of
such a collision.
If COLLISION PREVENTION ASSIST PLUS
detects that there is a risk of a collision, you will
be warned visually and acoustically. If you do not
react to the visual and audible collision warning,
autonomous braking can be initiated in critical
situations. If you apply the brake yourself in a
critical situation, the COLLISION PREVENTION
ASSIST PLUS adaptive Brake Assist assists you.
Important safety notes In particular, the detection of obstacles can be
impaired if: R
there is dirt on the sensors or anything else
covering the sensors R
there is snow or heavy rain R
there is interference by other radar sources R
there are strong radar reflections, for exam-
ple in parking garages R
a narrow vehicle traveling in front, e.g. a
motorbike R
a vehicle traveling in front on a different line R
new vehicles or after a service on the COLLI-
SION PREVENTION ASSIST PLUS system
Observe the notes in the section on breaking-
in ( Y
page 161).
Following damage to the front end of the vehicle,
have the configuration and operation of the
radar sensor checked at a qualified specialist
workshop. This also applies to collisions at slow
speeds where there is no visible damage to the
front of the vehicle.
Switching on/off
The COLLISION PREVENTION ASSIST PLUS is
automatically active after switching on the igni-
tion. You can activate or deactivate COLLISION PRE-
VENTION ASSIST PLUS in the on-board com-
puter ( Y
page 270). When deactivated, the dis-
tance warning function and the autonomous
braking function are also deactivated.
If COLLISION PREVENTION ASSIST PLUS is
deactivated, the

G WARNING
The distance warning function cannot always
clearly identify objects and complex traffic
situations.
In such cases, the distance warning function
may: R
give an unnecessary warning R
not give a warning
There is a risk of an accident.
Always pay careful attention to the traffic sit-
uation and do not rely solely on the distance
warning function. X
Brake immediately in order to increase the
distance from the vehicle in front.
or X
Take evasive action, provided it is safe to do
so.
Due to the nature of the system, particularly
complicated but non-critical driving conditions
may also cause the system to display a warning.
Autonomous braking function If the driver does not react to the distance warn-
ing signal in a critical situation, COLLISION PRE-
VENTION ASSIST PLUS can assist with the
autonomous braking function.
The autonomous braking function: R
gives the driver more time to react to critical
driving situations R
can help the driver to avoid an accident or R
reduces the effects of an accident
The autonomous braking function is available in
the following speed ranges: R
from 4 mph (7 km/h) to approx. 65 mph
(105 km/h) for moving objects R
from 4 mph (7 km/h) to approx. 31 mph
(50 km/h) for stationary objects
Due to the nature of the system, particularly
complicated but non-critical driving conditions
may also cause the Autonomous Braking Func-
tion to intervene.
If the autonomous braking function requires a
particularly high braking force, preventative
passenger protection measures (PRE-SAFE ®
)
are activated simultaneously ( Y
page 59). Adaptive Brake Assist General information
i Observe the "Important safety notes" sec-
tion ( Y
page 68).
With the help of adaptive Brake Assist, the dis-
tance warning signal can detect obstacles that
are in the path of your vehicle for an extended
period of time.
If adaptive Brake Assist detects a risk of colli-
sion with the vehicle in front, it calculates the
braking force necessary to avoid a collision. If
you apply the brakes forcefully, adaptive Brake
Assist will automatically increase the braking
force to a level suitable for the traffic conditions.
Adaptive Brake Assist provides braking assis-
tance in hazardous situations at speeds above
4 mph (7 km/h). It uses radar sensor technology
to assess the traffic situation.
Up to a speed of approximately 155 mph
(250 km/h), Adaptive Brake Assist is capable of
reacting to moving objects that have already
been detected as such at least once over the
period of observation.
Up to a speed of approximately 44 mph
(70 km/h), Adaptive Brake Assist reacts to sta-
tionary obstacles.
If adaptive Brake Assist demands particularly
high braking force, preventative passenger pro-
tection measures (PRE-SAFE ®
) are activated
simultaneously ( Y
page 59). X
Keep the brake pedal depressed until the
emergency braking situation is over.
ABS prevents the wheels from locking.
The brakes will work normally again if: R
you release the brake pedal. R
there is no longer any danger of a collision. R
no obstacle is detected in front of your vehi-
cle.
Adaptive Brake Assist is then deactivated.
Important safety notes
G WARNING
Adaptive Brake Assist cannot always clearly
identify objects and complex traffic situa-
tions.
In such cases, Adaptive Brake Assist can: R
intervene unnecessarily R
not intervene72
Driving safety systems
Safety

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.
G WARNING
Adaptive Brake Assist does not react: R
to people or animals R
to oncoming vehicles R
to crossing traffic R
when cornering
As a result, the Adaptive Brake Assist may not
intervene in all critical conditions. There is a
risk of an accident.
Always pay careful attention to the traffic sit-
uation and be ready to brake.
Due to the nature of the system, particularly
complicated but non-critical driving conditions
may also cause Adaptive Brake Assist to inter-
vene.
If adaptive Brake Assist is not available due to a
malfunction in the radar sensor system, the
brake system remains available with full brake
boosting effect and BAS.
ESP ®
(Electronic Stability Program)
General notes
i Observe 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 vehi-
cle 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)
i Observe the "Important safety notes" sec-
tion ( Y
page 68).
ETS traction control is part of ESP ®
. On vehicles
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 transfer-
red to the wheel or wheels with traction.
Traction control remains active, even if you
deactivate ESP ®
.
Important safety notes
G WARNING
If ESP ®
is malfunctioning, ESP ®
is unable to
stabilize the vehicle. Additionally, further driv-
ing safety systems are deactivated. This
increases the risk of skidding and an accident.
Drive on carefully. Have ESP ®
checked at a
qualified specialist workshop.
If the

If ESP ®
intervenes:X
Do not deactivate ESP ®
under any circum-
stances. X
Only depress the accelerator pedal as far as
necessary when pulling away. X
Adapt your driving style to suit the prevailing
road and weather conditions.
ECO start/stop function The ECO start/stop function is not available for
PLUG-IN HYBRID vehicles.
The ECO start/stop function switches the
engine off automatically when the vehicle stops
moving. The engine starts automatically when
the driver wants to pull away again. ESP ®
remains in its previously selected status. Exam-
ple: if ESP ®
was deactivated before the engine
was switched off, ESP ®
remains deactivated
when the engine is switched on again.
Deactivating/activating ESP ®
Important safety notes
i Observe the "Important safety notes" sec-
tion ( Y
page 68).
You can select between the following states of
ESP ®
:R
ESP ®
is activated.R
ESP ®
is deactivated.
G WARNING
If you deactivate ESP ®
, ESP ®
no longer sta-
bilizes the vehicle. There is an increased risk
of skidding and an accident.
Only deactivate ESP ®
in the situations descri-
bed in the following.
It may be best to deactivate ESP ®
in the follow-
ing situations: R
when using snow chains R
in deep snow R
on sand or gravel
i Activate ESP ®
as soon as the situations
described above no longer apply. ESP ®
will
otherwise not be able to stabilize the vehicle if
the vehicle starts to skid or a wheel starts to
spin. ! Avoid spinning the driven wheels for an
extended period with ESP ®
deactivated. You
could otherwise damage the drivetrain.
Deactivating/activating ESP ®
You can deactivate or activate ESP ®
via the on-
board computer ( Y
page 269).
ESP ®
deactivated:
The

Important safety notes
G WAR NING
If road and weather conditions are poor,
trailer st abiliz ation will not be able to prevent
the veh icle/t railer co mbin ation from swerv-
ing. Trailers wit h a high center of gravity can
tip over before ESP ®
can detect this. There is
a risk of an acc iden t.
Always adapt your driv ing style to the prevail-
ing road and weather conditions.
If your veh icle wit h trailer (veh icle/t railer com-
bin ation) begins to lurch, you can on ly st abiliz e
the veh icle/t railer co mbin ation by depr essing
the brake firmly.
ESP ®
trailer st abiliz ation is active above spee ds
of about 65 km/h.
ESP ®
trailer st abiliz ation does not work if ESP ®
is deactivated or disabled because of a malfunc-
tion.
Crosswind Assist (vehicles without
MAGIC BODY CONTROL)
General information Veh icle s wit h MAGIC BODY CONTROL: informa-
tion on st abiliz ing the veh icle in the event of
cross win d ( Y
page 210).
St rong cross winds can cause your veh icle to
deviate from a straight course. The cross win d
driv ing assistance function integrated in ESP ®
noticeably reduces these impairments.
ESP ®
intervenes automatical ly according to the
dire ction and intensity of the cross winds affect-
ing your veh icle .
ESP intervenes wit h st abiliz ing braking to assist
you in ke epin g the veh icle in the lane.
Cros swin d Assist is active at veh icle spee ds
above 50 mph (80 km/h) when driv ing straight
ahead or cornering gently.
Important safety notes
Cros swin d Assist does not work if ESP ®
is
swit ched off or deactivated because of a mal-
function. EBD (electronic brake force distribu-
tion)
General information EBD monitors and controls the brake pressure
on the rear wheels to improve driving stability
while braking.
Important safety notes
i Observe the "Important safety notes" sec-
tion ( Y
page 68).
G WARNING
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 han dlin g characteristics. Have
the brake system checked at a qualified spe-
cialist workshop.
Observe information regarding indicator and
warning lamps ( Y
page 316) as well as display
messages ( Y
page 280).
ADAPTIVE BRAKE ADAPTIVE BRAKE enhances braking safety and
offers increased braking comfort. In addition to
the braking function, ADAPTIVE BRAKE also has
the HOLD function ( Y
page 208) and hill start
assist ( Y
page 165).
PRE-SAFE ®
Brake
General information PRE-SAFE ®
Brake can help you to minimize the
risk of a collision with a vehicle ahead or a
pedestrian, 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.
i Pay attention to the important safety notes
in the "Driving safety systems" section
( Y
page 68).
PRE ‑ SAFE ®
Brake is on ly availab le in vehicles
wit h the Driving Assistance Plus package.Driving safety systems 75
Safety Z

For PRE-SAFE ®
Brake to assist you when driving,
the radar sensor system and the camera system
must be switched on and be operational.
With the help of the radar sensor system and the
camera system, PRE-SAFE ®
Brake can detect
obstacles that are in front of your vehicle for an
extended period of time.
In addition, pedestrians in the path of your vehi-
cle can be detected.
PRE-SAFE ®
Brake detects pedestrians using
typical characteristics such as the body con-
tours and posture of a person standing upright.
i Observe the restrictions described in the
"Important safety notes" sec-
tion“ ( Y
page 76).
Important safety notes
G WARNING
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 brake yourself. Even
after subsequent full application of the brakes
a collision cannot always be avoided, partic-
ularly when approaching at too high a speed.
There is a risk of an accident.
Always apply the brakes yourself and try to
take evasive action, provided it is safe to do
so.
In the event of a partial application of the brakes,
the vehicle is braked with up to 50% of the full
braking pressure.
G WARNING
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. G WARNING
PRE-SAFE ®
Brake cannot always clearly iden-
tify people, especially if they are moving. In
these cases, PRE-SAFE ®
Brake cannot inter-
vene. 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.
In order to maintain the appropriate distance to
the vehicle in front and thus prevent a collision,
you must apply the brakes yourself.
G WARNING
PRE-SAFE ®
Brake does not react: R
to small people, e.g. children R
to 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.
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 exam-
ple 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
Recognition by the camera system is also
impaired in the event of: R
dirt on the camera or if the camera is covered R
there is glare on the camera system, e.g. from
the sun being low in the sky76
Driving safety systems
Safety

Useful information
i This Operator's Manual describes all models
and all standard and optional equipment of
your vehicle available at the time of publica-
tion of the Operator's Manual. Country-spe-
cific 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 specialist
workshops ( Y
page 28).
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 332). 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 check which periodically establishes a radio
connection between the vehicle and the Smart-
Key determines whether a valid SmartKey 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
SmartKey functions
C
7 To lock the vehicle
D
T To open/close the trunk lid