BAS (Brake Assist System)
General information BAS operates in emergency braking situations.
If you depress the brake pedal quickly, BAS
automatically boosts the braking force, thus
shortening the stopping distance.
Important safety notes
i Observe the "Important safety notes" sec-
tion ( Y
page 66).
G WARNING
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.
Active Brake Assist
General information
i Observe the "Important safety notes" sec-
tion ( Y
page 66).
Active Brake Assist consists of a distance warn-
ing function with an autonomous braking func-
tion and Adaptive Brake Assist.
Active Brake Assist can help you to minimize the
risk of a collision with the vehicle traveling in
front or reduce the effects of such a collision.
If Active Brake Assist detects that there is a risk
of 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, Adap-
tive Brake Assist of the Active Brake Assist sys-
tem supports 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 is traveling in front, e.g. a
motorbike R
a vehicle is traveling in front on a different line R
you are driving a new vehicle or servicing on
the Active Brake Assist system has just been
carried out
Observe the important safety notes in the
"Breaking-in notes" section ( Y
page 135).
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.
Activating/deactivating Active Brake Assist is automatically active after
switching on the ignition.
You can activate or deactivate Active Brake
Assist ( Y
page 232) in the on-board computer.
When deactivated, the distance warning func-
tion and the autonomous braking function are
also deactivated.
If Active Brake Assist is deactivated, the
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 58).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
i Observe the "Important safety notes" sec-
tion for driving safety systems ( Y
page 66).
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 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.
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.
Always adapt your speed to suit the prevailing
road and traffic conditions.
Due to the nature of the system, particularly
complicated but non-critical driving conditions
may also cause Brake Assist to intervene.
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 66).
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 66).
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 ®
.Driving safety systems 69
Safety Z