Abs MERCEDES-BENZ CLA-Class 2015 C117 User Guide

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

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

i
If the SmartKey battery is checked within
the signal reception range of the vehicle,
pressing the &or% button:
R locks or
R unlocks the vehicle
i You can get a battery at any qualified spe-
cialist workshop.
Replacing the battery You require a CR 2025 3 V cell battery.
X Take the mechanical key out of the Smart-
Key (Y page 76). X
Press mechanical key ;into the opening
in the SmartKey in the direction of the
arrow until battery tray cover :opens.
When doing so, do not hold cover :shut.
X Remove battery tray cover :.X
Repeatedly tap the SmartKey against your
palm until battery =falls out.
X Insert the new battery with the positive ter-
minal facing upwards. Use a lint-free cloth
to do so. X
Make sure that the surface of the battery is
free of lint, grease and other contaminants.
X Insert the front tabs of battery tray cover :
and then press to close it.
X Insert mechanical key into the SmartKey
(Y page 77).
X Check the function of all SmartKey buttons
on the vehicle. 78
SmartKeyOpening and closing

4MATIC
! Never tow the vehicle with one axle
raised. This may damage the differential.
Damage of this sort is not covered by the
Mercedes-Benz Limited Warranty. All
wheels must remain either on the ground or be fully raised. Observe the instructions for
towing the vehicle with all wheels in full
contact with the ground.
4MATIC, together with ESP ®
, improves the
traction of your vehicle whenever a drive
wheel spins due to insufficient grip.
If you fail to adapt your driving style, 4MATIC
can neither reduce the risk of accident nor
override the laws of physics. 4MATIC cannot
take account of road, weather and traffic con- ditions. 4MATIC is only an aid. You are
responsible for the distance to the vehicle in
front, for vehicle speed, for braking in good
time and for staying in your lane.
If a drive wheel spins due to insufficient grip:
R Only depress the accelerator pedal as far as
necessary when pulling away.
R Accelerate less when driving.
i In wintry driving conditions, the maximum
effect of 4MATIC can only be achieved if
you use winter tires (M+S tires), with snow
chains if necessary. PARKTRONIC
Important safety notes PARKTRONIC is an electronic parking aid with
ultrasonic sensors. It monitors the area
around your vehicle using six sensors in the
front bumper and six sensors in the rear
bumper. PARKTRONIC indicates visually and
audibly the distance between your vehicle
and an object.
PARKTRONIC is only an aid. It is not a replace-
ment for your attention to your immediate
surroundings. You are always responsible for
safe maneuvering, parking and exiting a park- ing space. When maneuvering, parking or pulling out of a parking space, make sure that
there are no persons, animals or objects in
the area in which you are maneuvering.
! When parking, pay particular attention to
objects above or below the sensors, such
as flower pots or trailer drawbars.
PARKTRONIC does not detect such objects
when they are in the immediate vicinity of
the vehicle. You could damage the vehicle
or the objects.
The sensors may not detect snow and other
objects that absorb ultrasonic waves.
Ultrasonic sources such as an automatic
car wash, the compressed-air brakes on a
truck or a pneumatic drill could cause
PARKTRONIC to malfunction.
PARKTRONIC may not function correctly on uneven terrain.
PARKTRONIC is activated automatically when you:
R switch on the ignition
R shift the transmission to position D,Ror N
R release the electric parking brake
Range of the sensors General notes
PARKTRONIC does not take objects into con-
sideration that are:
R below the detection range, e.g. people, ani-
mals or objects.
R above the detection range, e.g. overhang-
ing loads, truck overhangs or loading
ramps. Driving systems
181Driving and parking Z

R
the lane markings are worn away, dark or
covered up, e.g. by dirt or snow
R the distance to the vehicle in front is too
small and the lane markings thus cannot be
detected
R the lane markings change quickly, e.g.
lanes branch off, cross one another or
merge
R the road is narrow and winding
R there are strong shadows cast on the road
Switching on Lane Keeping Assist
X Activate Lane Keeping Assist using the on-
board computer; to do so, select Standard
Standard
or Adaptive Adaptive (Ypage 211).
If you drive at speeds above 60 km/h and
lane markings are detected, the lane mark- ings in the assistance graphics display
(Y page 209) are shown in green.
When Standard
Standard is selected, no warning vibra-
tion occurs if:
R you have switched on the turn signals. In
this event, the warnings are suppressed for
a certain period of time.
R a driving safety system intervenes, such as
ABS, BAS or ESP ®
.
When Adaptive
Adaptive is selected, no warning vibra-
tion occurs if:
R you have switched on the turn signals. In
this event, the warnings are suppressed for a certain period of time.
R a driving safety system intervenes, e.g.
ABS, BAS or ESP ®
.
R you accelerate hard, e.g. kickdown.
R you brake hard.
R you steer actively, e.g. swerve to avoid an
obstacle or change lanes quickly.
R you cut the corner on a sharp bend.
In order that you are warned only when nec-
essary and in good time if you cross the lane marking, the system recognizes certain con-
ditions and warns you accordingly. The warning vibration occurs earlier if:
R you approach the outer lane marking on a
bend.
R the road has very wide lanes, e.g. a high-
way.
R the system recognizes solid lane markings.
The warning vibration occurs later if:
R the road has narrow lanes.
R you cut the corner on a bend. Driving systems
197Driving and parking Z

Safety systems
Display messages
Possible causes/consequences and
M
MSolutions !÷
Currently Unavail‐ Currently Unavail‐
able See Opera‐ able See Opera‐
tor's Manual tor's Manual ABS (Anti-lock Braking System), BAS (Brake Assist), ESP
®
(Elec-
tronic Stability Program), the HOLD function and hill start assist
are temporarily unavailable.
COLLISION PREVENTION ASSIST PLUS may also have failed.
In addition, the !,÷andå warning lamps may light up
in the instrument cluster.
ATTENTION ASSIST is deactivated.
Possible causes are:
R self-diagnosis is not yet complete.
R the on-board voltage may be insufficient.
G WARNING
The brake system continues to function normally, but without the functions listed above. The wheels could therefore lock if you
brake hard, for example.
The steerability and braking characteristics may be severely affec-ted. The braking distance in an emergency braking situation can
increase.
If ESP ®
is not operational, ESP ®
is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
X Carefully drive a short distance on a suitable stretch of road,
making slight steering movements at a speed above 12 mph
(20 km/h).
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed: X Drive on carefully.
X Visit a qualified specialist workshop. !÷
Inoperative See Inoperative See
Operator's Manual Operator's Manual ABS, BAS, ESP
®
, the HOLD function and hill start assist are not
available due to a malfunction.
COLLISION PREVENTION ASSIST PLUS may also have failed.
The !, ÷,åand$ (USA only)/J (Canada only)
warning lamps in the instrument cluster may also light up.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the functions listed above. The wheels could therefore lock if you
brake hard, for example. 218
Display messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions ÷
Inoperative See Inoperative See
Operator's Manual Operator's Manual ESP
®
, BAS, the HOLD function and hill start assist are unavailable
due to a malfunction.
COLLISION PREVENTION ASSIST PLUS may also have failed.
In addition, the ÷andå warning lamps may light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the functions listed above.
The braking distance in an emergency braking situation can thus
increase.
If ESP ®
is not operational, ESP ®
is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
X Drive on carefully.
X Visit a qualified specialist workshop. T!
÷
Inoperative See Inoperative See
Operator's Manual Operator's Manual EBD (electronic brake force distribution), ABS, BAS, ESP
®
, the
HOLD function and hill start assist are not available due to a mal- function.
COLLISION PREVENTION ASSIST PLUS may also have failed.
A warning tone sounds.
In addition, the ÷,åand! warning lamps may light up
in the instrument cluster.
G WARNING
The brake system continues to function normally, but without the functions listed above. The front and rear wheels could therefore
lock if you brake hard, for example.
The steerability and braking characteristics may be severely affec-ted. The braking distance in an emergency braking situation can
increase.
If ESP ®
is not operational, ESP ®
is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
X Drive on carefully.
X Visit a qualified specialist workshop immediately. 220
Display
messagesOn-board computer and displays

Problem
Possible causes/consequences and
M
MSolutions !
The yellow ABS warning
lamp is lit while the
engine is running. ABS (Anti-lock Braking System) is deactivated due to a malfunc-
tion. Therefore, BAS (Brake Assist), COLLISION PREVENTION
ASSIST PLUS, ESP ®
(Electronic Stability Program), the HOLD func-
tion and hill start assist are also deactivated, for example.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the functions listed above. The wheels could therefore lock if you
brake hard, for example.
The steerability and braking characteristics may be severely affec-ted. The braking distance in an emergency braking situation can
increase.
If ESP ®
is not operational, ESP ®
is unable to stabilize the vehicle.
There is an increased risk of skidding and an accident.
X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop.
If the ABS control unit is faulty, there is also a possibility that other
systems, such as the navigation system or the automatic trans-
mission, will not be available. 250
Warning and indicator lamps in the instrument clusterOn-board computer and displays

Problem
Possible causes/consequences and
M
MSolutions !
The yellow ABS warning
lamp is lit while the
engine is running. ABS is temporarily unavailable. Therefore, BAS, COLLISION PRE-
VENTION ASSIST PLUS, ESP
®
, EBD (electronic brake force distri-
bution), the HOLD function and hill start assist are also deactiva-
ted, for example.
Possible causes are:
R self-diagnosis is not yet complete.
R the on-board voltage may be insufficient.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the functions listed above. The front and rear wheels could therefore
lock if you brake hard, for example.
The steerability and braking characteristics may be severely affec-ted. The braking distance in an emergency braking situation can
increase.
If ESP ®
is not operational, ESP ®
is unable to stabilize the vehicle.
There is a risk of an accident.
X Carefully drive a suitable distance, making slight steering move-
ments at a speed above 12 mph (20 km/h).
The functions mentioned above are available again when the
warning lamp goes out.
If the warning lamp is still on: X Observe the additional display messages in the multifunction
display.
X Drive on carefully.
X Visit a qualified specialist workshop. Warning and indicator lamps in the instrument cluster
251On-board computer and displays Z