2015 MERCEDES-BENZ CLA-Class Owner's Manual

Driving safety systems
Overview of driving safety systems
In this section, you will find information about the following driving safety systems:
R ABS (Anti-lock BrakingSystem)
(Y page 63)
R BAS (Brake Assist System) (Y page 64)
R COLLISION PREVENTION ASSIST PLUS
(Y page 64)
R ESP ®
(Electronic StabilityProgram)
(Y page 67)
R EBD (Electronic Brake forceDistribution)
(Y page 70)
R ADAPTIVE BRAKE (Y page 70)
R STEER CONTROL (Y page 70) 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 maintaining
the distance to the vehicle in front, for vehicle speed, for braking in good time, and for stay-ing in lane. Always adapt your driving style to
suit the prevailing road and weather condi-
tions 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 318).
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 ! 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 i
Observe the "Important safety notes" sec-
tion (Y page 63). G
WARNING
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 250) and
display messages which may be shown in the
instrument cluster (Y page 218).
ABS works from a speed of about 5 mph
(8 km/ h), regardless of road-surface condi-
tions. ABS works on slippery surfaces, even
when you only brake gently.
Braking 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. Driving safety systems
63Safety Z

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 i
Observe the "Important safety notes" sec-
tion (Y page 63). 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. COLLISION PREVENTION ASSIST
PLUS
General information COLLISION PREVENTION ASSIST PLUS con-
sists of a distance warning function with an
autonomous emergency 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
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
R new vehicles or after a service on the COL-
LISION PREVENTION ASSIST PLUS system
Observe the notes in the section on break- ing-in (Y page 140).
Following damage to the front end of the vehi- cle, have the configuration and operation of
the radar sensor 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.
Distance warning function Important safety notes
i Observe the "Important safety notes" sec-
tion for driving safety systems (Y page 63).64
Driving safety systemsSafety

G
WARNING
The distance warning function does not react:
R to people or animals
R to oncoming vehicles
R to crossing traffic
R when cornering
Thus, the distance warning function cannot
provide a warning in all critical situations.
There is a risk of an accident.
Always pay careful attention to the traffic sit-
uation and be ready to brake. 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.
Function X To activate/deactivate: activate or deac-
tivate the distance warning function in the
on-board computer (Y page 210).
If the distance warning function is not activa-
ted, the æsymbol appears in the assis-
tance graphics display.
The distance warning function 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 the distance warning function
detects that there is a risk of a collision, you
will be warned visually and acoustically.
Starting at a speed of around 4 mph (7 km/h),
the distance warning 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 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 condi-
tions may also cause the system to display a
warning.
With the help of the radar sensor system, the
distance warning function can detect obsta-
cles that are in the path of your vehicle for an extended period of time.
Up to a speed of around 44 mph (70 km/h),
the distance warning function can also react
to stationary obstacles, such as stopped or
parked vehicles.
If you approach an obstacle and the distance
warning function detects a risk of a collision,
the system will initially alert you both visually
and acoustically.
Autonomous braking function If the driver does not react to the distance
warning signal in a critical situation, COLLI-
SION PREVENTION ASSIST PLUS can assist
with the autonomous braking function.
The autonomous braking function:
R gives the driver more time to react to criti-
cal driving situations
R can help the driver to avoid an accident or
R reduces the effects of an accident
Vehicles without DISTRONIC PLUS: the
autonomous braking function is available in
the following speed ranges:
R 5 - 65 mph (7 - 105 km/h) for moving
objects
R 5 - 31 mph (7 - 50 km/h) for stationary
objects Driving safety systems
65Safety Z

Vehicles with DISTRONIC PLUS:
the auton-
omous braking function is available in the fol- lowing speed ranges:
R 5 - 124 mph (7 - 200 km/h) for moving
objects
R 5 - 31 mph (7 - 50 km/h) for stationary
objects
If the autonomous braking function requires a particularly high braking force, preventative
passenger protection measures (PRE-SAFE ®
)
are activated simultaneously.
Adaptive Brake Assist i
Observe the "Important safety notes" sec-
tion (Y page 63).
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. 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. Due to the nature of the system, particularly
complicated but non-critical driving condi-
tions may also cause Brake Assist to inter-
vene.
If adaptive Brake Assist is not available due to a malfunction in the radar sensor system, thebrake system remains available with full
brake boosting effect and BAS.
With the help of adaptive Brake Assist, the
distance 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 col-
lision with the vehicle in front, it calculates
the braking force necessary to avoid a colli-
sion. If you apply the brakes forcefully, adap-
tive Brake Assist will automatically increase
the braking force to a level suitable for the
traffic conditions.
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
vehicle.
Adaptive Brake Assist is then deactivated.
If adaptive Brake Assist demands particularly
high braking force, preventative passenger
protection measures (PRE-SAFE ®
) are activa-
ted simultaneously.
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
stationary obstacles. 66
Driving safety systemsSafety

ESP
®
(Electronic Stability Program)
General notes i
Observe the "Important safety notes" sec-
tion (Y page 63).
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) i
Observe the "Important safety notes" sec-
tion (Y page 63).
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 ®
.
Important safety notes i
Observe the "Important safety notes" sec-
tion (Y page 63). 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. Vehicles without 4MATIC:
when towing
your vehicle with the front axle raised, it is
important that you observe the notes on ESP ®
(Y page 313).
ESP ®
is only deactivated if the åwarning
lamp is lit continuously.
If the ÷ warning lamp and the åwarn-
ing lamp are lit continuously, ESP ®
is not
available due to a malfunction.
Observe the information on warning lamps
(Y page 252) and display messages which
may be shown in the instrument cluster
(Y page 218).
Only use wheels with the recommended tire
sizes. Only then will ESP ®
function properly.
Characteristics of ESP ® General information
If the
÷ ESP®
warning lamp goes out
before beginning the journey, ESP ®
is auto-
matically active.
If ESP ®
intervenes, the ÷ESP®
warning
lamp flashes in the instrument cluster.
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 prevail-
ing road and weather conditions.
ECO start/stop function
The ECO start/stop function switches the
engine off automatically when the vehicle
stops moving. The engine starts automati-
cally when the driver wants to pull away again. ESP ®
remains in its previously selected sta-
tus. Example: if ESP®
was deactivated before
the engine was switched off, ESP ®
remains
deactivated when the engine is switched on
again. Driving safety systems
67Safety Z

Deactivating/activating ESP
®
(except
AMG vehicles) Important safety notes
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 fol-
lowing 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 vehi-
cle 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 210).
ESP ®
deactivated:
The å ESP®
OFF warning lamp in the
instrument cluster lights up.
ESP ®
activated:
The å ESP®
OFF warning lamp in the
instrument cluster goes out.
Characteristics when ESP ®
is deactivated
If ESP ®
is deactivated and one or more wheels
start to spin, the ÷ESP®
warning lamp in the instrument cluster flashes. In such situa-
tions, ESP ®
will not stabilize the vehicle.
If you deactivate ESP ®
:
R ESP ®
no longer improves driving stability.
R engine torque is no longer limited and the
drive wheels are able to spin.
The spinning of the wheels results in a cut-
ting action for better traction on loose sur-faces.
R traction control is still activated.
R ESP ®
still provides support when you
brake.
Deactivating/activating ESP ®
(AMG
vehicles) Important safety notes
i Observe the "Important safety notes" sec-
tion (Y page 63).
You can select between the following states
of ESP ®
:
R ESP ®
is activated.
R SPORT handling mode is activated.
R ESP ®
is deactivated. G
WARNING
When SPORT handling mode is activated,
there is a greater risk of skidding and acci-
dents.
Only activate SPORT handling mode in the sit- uations described in the following. 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.
In the following situations, it may be better to activate SPORT handling mode or deactivate
ESP ®
:
R when using snow chains
R in deep snow 68
Driving safety syste
msSafety

R
on sand or gravel
R on designated roads when the vehicle's
own oversteering and understeering char-
acteristics are desired
Driving in SPORT handling mode or without
ESP ®
requires an extremely qualified and
experienced driver.
i Activate ESP ®
as soon as the situations
described above no longer apply. ESP ®
will
otherwise not be able to stabilize the vehi-
cle 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 ®X
To activate SPORT handling mode:
briefly press button :.
The M SPORT handling mode warning
lamp in the instrument cluster lights up.
The SPORT handling mode SPORT handling mode message
appears in the multifunction display.
X To deactivate SPORT handling mode:
briefly press button :.
The M SPORT handling mode warning
lamp in the instrument cluster goes out. X
To deactivate ESP ®
:press button :until
the å ESP®
OFF warning lamp lights up
in the instrument cluster.
The ÷ OFF
OFF message appears in the mul-
tifunction display.
X To activate ESP ®
:briefly press button :.
The å ESP®
OFF warning lamp in the
instrument cluster goes out. The ÷
ESP ®
ON ON message appears in the multifunc-
tion display.
Characteristics of activated SPORT han-
dling mode
If SPORT handling mode is activated and one or more wheels start to spin, the ÷ESP®
warning lamp in the instrument cluster
flashes. ESP ®
only stabilizes the vehicle to a
limited degree.
When SPORT handling mode is activated:
R ESP ®
only improves driving stability to a
limited degree.
R traction control is still activated.
R engine torque is restricted to a limited
degree and the drive wheels are able to
spin.
The spinning of the wheels results in a cut-
ting action for better traction on loose sur- faces.
R ESP ®
still provides support when you
brake.
Characteristics when ESP ®
is deactivated
If ESP ®
is deactivated and one or more wheels
start to spin, the ÷ESP®
warning lamp in
the instrument cluster does not flash. In such
situations, ESP ®
will not stabilize the vehicle.
If you deactivate ESP ®
:
R ESP ®
no longer improves driving stability.
R engine torque is no longer limited and the
drive wheels are able to spin.
The spinning of the wheels results in a cut-
ting action for better traction on loose sur- faces.
R traction control is still activated. Driving safety systems
69Safety Z

R
PRE-SAFE ®
is no longer available, nor is it
activated if you brake firmly and ESP ®
intervenes.
R COLLISION PREVENTION ASSIST is no lon-
ger available; nor is it activated if you brake
firmly with assistance from ESP ®
.
R ESP ®
still provides support when you
brake.
ESP ®
trailer stabilization General information
If your vehicle/trailer combination begins to
swerve, ESP
®
assists you in this situation.
ESP ®
slows the vehicle down by braking and
limiting the engine output until the vehicle/
trailer combination has stabilized.
Important safety notes G
WARNING
If road and weather conditions are poor,
trailer stabilization will not be able to prevent the vehicle/trailer combination from swerv-
ing. Trailers with a high center of gravity can
tip over before ESP ®
can detect this. There is
a risk of an accident.
Always adapt your driving style to the prevail- ing road and weather conditions.
If your vehicle with trailer (vehicle/trailer
combination) begins to lurch, you can only
stabilize the vehicle/trailer combination by
depressing the brake firmly.
ESP ®
trailer stabilization is active above
speeds of about 65 km/h.
ESP ®
trailer stabilization does not work if
ESP ®
is deactivated or disabled because of a
malfunction. 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 i
Observe the "Important safety notes" sec-
tion (Y page 63). 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 handling characteristics. Have the brake system checked at a qualified spe-
cialist workshop.
Observe information regarding indicator and
warning lamps (Y page 250) as well as dis-
play messages (Y page 220). ADAPTIVE BRAKE
ADAPTIVE BRAKE enhances braking safety
and offers increased braking comfort. In addi- tion to the braking function, ADAPTIVE BRAKE
also has the HOLD function (Y page 178)and
hill start assist (Y page 145). STEER CONTROL
General information STEER CONTROL helps you by transmitting a
noticeable steering force to the steering
wheel in the direction required for vehicle
stabilization. 70
Driving safety systemsSafety