page 11 MERCEDES-BENZ B-CLASS HATCHBACK 2015 Service Manual

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.
With the help of the radar sensor system, the
distance warning function can detect obstacles
that are in the path of your vehicle for an exten-
ded period of time.
Up to a speed of approximately 70 km/h, the
distance warning function can also react to sta-
tionary obstacles, such as stopped or parked
vehicles.
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 7 - 105 km/h for moving objects
R 7 - 50 km/h for stationary objects
Due to the nature of the system, complicated
but non-critical driving conditions may also
cause the Autonomous Braking function to
intervene.
If the autonomous braking function demands
particularly high braking force, preventative
passenger protection measures (PRE-SAFE ®
)
are activated simultaneously (Y page 48).
Adaptive Brake Assist General notes
i Observe the "Important safety notes" sec-
tion (Y page 61).
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
7 km/h. It uses radar sensor technology to
assess the traffic situation.
Up to a speed of approximately 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 obser-
vation.
Up to a speed of approximately 70 km/h, Adap-
tive Brake Assist reacts to stationary obstacles.
If Adaptive Brake Assist demands particularly
high braking force, preventative passenger pro-
tection measures (PRE-SAFE ®
) are activated
simultaneously (Y page 48).
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.
Important safety notes
i Observe the "Important safety notes" sec-
tion for driving safety systems (Y page 61). 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. 64
Driving safety systemsSafety

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 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. Adaptive brake lights
The adaptive brake lights warn following traffic
in an emergency braking situation:
R by flashing brake lamps
R the hazard warning lamps are activated
If you brake sharply from a speed of more than
50 km/h or if braking is assisted by BAS or BAS
PLUS, the brake lamps flash rapidly. In this way,
traffic travelling behind you is warned in an even more noticeable manner.
If you brake sharply from a speed of more than
70 km/h to a standstill, the hazard warning
lamps are activated automatically. If the brakes
are applied again, the brake lamps light up con- tinuously. The hazard warning lamps switch off
automatically if you travel faster than 10 km/h. You can also switch off the hazard warning
lamps using the hazard warning button
(Y page 100). ESP
®
(Electronic Stability Program)
General notes i
Observe the "Important safety notes" sec-
tion (Y page 61). ESP
®
monitors driving stability and traction, i.e.
power transmission between the tyres 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 stabilise 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 stabilise
the vehicle during braking.
ETS (Electronic Traction System) i
Observe the "Important safety notes" sec-
tion (Y page 61).
ETS traction control 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 if you deactivate
ESP ®
.
Important safety notes i
Observe the "Important safety notes" sec-
tion (Y page 61). G
WARNING
If ESP ®
is malfunctioning, ESP ®
is unable to
stabilise the vehicle. In addition, other driving
safety systems are switched off. This increa-
ses the risk of skidding and an accident.
Drive on carefully. Have ESP ®
checked at a
qualified specialist workshop.
When towing your vehicle with the front axle
raised, observe the notes on ESP ®
(Y page 262).
When towing your vehicle away with the rear
axle raised, observe the notes on ESP ®
(Y page 262).
If the å ESP®
OFF warning lamp lights up
continuously, ESP ®
is deactivated.
If the ÷ ESP®
warning lamp and the å
warning lamp are lit continuously, ESP ®
is not
available due to a malfunction. Driving safety systems
65Safety Z

Observe the information on warning lamps
(Y page 218) and display messages which may
be shown in the instrument cluster
(Y page 190).
Only use wheels with the recommended tyre
sizes. Only then will ESP ®
function properly.
Characteristics of ESP ®Characteristics of ESP
®
If the ÷ ESP warning lamp goes out before
beginning the journey, ESP ®
is automatically
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 When pulling away, only depress the acceler-
ator pedal as far as is necessary.
X Adapt your driving style to suit the prevailing
road and weather conditions.
Deactivating/activating ESP ®Important safety notes
You can select between the following statuses
of ESP ®
:
R ESP ®
is activated
R ESP ®
is deactivated G
WARNING
If you deactivate ESP ®
, ESP ®
no longer sta-
bilises 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 stabilise the vehicle
if the vehicle starts to skid or a wheel starts to
spin. Deactivating/activating ESP
®
You can deactivate or activate ESP ®
via the on-
board computer (Y page 182).
ESP ®
deactivated:
The å ESP®
OFF warning lamp in the instru-
ment cluster lights up.
ESP ®
activated:
The å ESP®
OFF warning lamp in the instru-
ment 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 situations,
ESP ®
will not stabilise 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 cutting
action for better traction on loose surfaces.
R Traction control is still activated
R COLLISION PREVENTION ASSIST is no longer
available; nor is it activated if you brake firmly
with assistance from ESP ®
R PRE-SAFE ®
is no longer available; it is also not
activated if you brake firmly with assistance
from ESP ®
R ESP ®
still provides support when you brake
firmly EBD (electronic brake force distribu-
tion)
General notes 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 61). 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. 66
Driving safety systemsSafety

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 216) as well as display
messages (Y page 192). 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 154) and hill start
assist (Y page 128). STEER CONTROL
General notes STEER CONTROL helps you by transmitting a
noticeable steering force to the steering wheel
in the direction required for vehicle stabilisation.
This steering support is provided in particular if:
R both right wheels or both left wheels are on a
wet or slippery road surface when you brake
R the vehicle starts to skid
Important safety notes i
Observe the "Important safety notes" sec-
tion (Y page 61).
No steering support is provided from STEER
CONTROL, if: R ESP ®
is malfunctioning
R the steering is faulty
If ESP ®
is malfunctioning, you will be assisted
further by the electrical power steering. Recuperative Brake System
G
WARNING
In the event of malfunctions in the Recupera- tive Brake System, the following may occur: R
the braking performance of the electric
motor may be either reduced or not effec-
tive
R brake pedal resistance may be lower than
usual
R pedal travel may be longer than usual
If you do not make an additional effort to apply the brake yourself, the braking effect may not
be sufficient. There is a risk of an accident.
In the event of a malfunction, depress the
brake pedal further. The brake system is still
fully functional.
Observe the important safety notes on driving
safety systems (Y page 61).
The Recuperative Brake System converts the
kinetic energy when braking into electrical
energy. The electric motor is used as an alter-
nator during braking. This electrical energy is
then stored in the high-voltage battery.
You can find information about manually adjust- able recuperation under "Steering wheel gear-
shift paddles" (Y page 132).
If the warning light in the instrument cluster is lit up, there is a motor malfunction or a brake mal-
function.
Observe information regarding indicator and
warning lamps (Y page 215) as well as display
messages (Y page 190). Protection against theft
Immobiliser
The immobiliser prevents your vehicle from
being started without the correct key.
X To activate with the key: remove the key
from the ignition lock.
X To activate with KEYLESS-GO start func-
tion or KEYLESS-GO:
switch the ignition off
and open the driver's door.
X To deactivate: switch on the ignition.
When leaving the vehicle, always take the key
with you and lock the vehicle. Anyone can start
the drive system if a valid key has been left
inside the vehicle.
i The immobiliser is always deactivated when
you start the drive system. Protection against theft
67Safety Z

ATA (Anti-Theft Alarm system)
X
To prime: lock the vehicle with the key or
KEYLESS-GO.
Indicator lamp :flashes. The alarm system
is primed after approximately 15 seconds.
X To deactivate: unlock the vehicle with the
key or KEYLESS-GO.
or X Insert the key into the ignition lock.
A visual and audible alarm is triggered if the
alarm system is primed and you open: R a door
R the vehicle with the emergency key element
R the tailgate
R the bonnet
X To switch the alarm off with the key: press
the % or& button on the key.
The alarm is deactivated.
or X Vehicles with KEYLESS-GO start-function
or KEYLESS-GO: remove the Start/Stop but-
ton from the ignition lock (Y page 126).
X Insert the key into the ignition lock.
The alarm is deactivated.
X To deactivate the alarm using KEYLESS-
GO:
grasp the outside door handle. The key
must be outside the vehicle.
The alarm is deactivated.
or X Press the Start/Stop button on the dash-
board. The key must be inside the vehicle.
The alarm is deactivated.
The alarm is not switched off, even if you close
the open door that has triggered it, for example.
i If the alarm stays on for more than
30 seconds, the Mercedes ‑Benz emergencycall system automatically sends a message to
the Customer Assistance Centre. This is done by means of a text message or a data con-
nection.
The emergency call system sends a message
or establishes a data connection provided
that:
R you have subscribed to the Mercedes ‑Benz
emergency call system
R the Mercedes‑Benz emergency call system
has been activated properly
R the necessary mobile phone network is
available Tow-away protection
Function An audible and visual alarm is triggered if your
vehicle's angle of inclination is altered while
tow-away protection is primed. This can occur if
the vehicle is jacked up on one side, for exam-
ple.
Activating X
Make sure that:
R the doors are closed
R the tailgate is closed
Only then is tow-away protection primed.
X Lock the vehicle with the key or KEYLESS-GO.
Tow-away protection is primed after approx-
imately 60 seconds.
Switching off X
Unlock the vehicle with the key or KEYLESS-
GO.
or X Insert the key into the ignition lock.
Tow-away protection is switched off automat-
ically. 68
Protection against theftSafety

The interior motion sensor remains deactivated
until:
R the vehicle is unlocked again and
R a door is opened and closed again and
R the vehicle is locked again
To prevent a false alarm, deactivate the interior
motion sensor if you lock your vehicle and:
R people or animals remain in the vehicle
R the side windows remain open
i UK only:
your vehicle is equipped with a
double-lock function. The doors cannot be
opened from the inside if the vehicle has been
locked with the key (Y page 78). Deactivate
the interior motion sensor before you lock the
vehicle with the key. The doors can then be
opened from the inside after the vehicle has
been locked from the outside with the key.
Observe the "Important safety notes"
(Y page 78). 70
Protection against theftSafety

Useful information
i This Owner's Manual describes all models,
series and optional equipment for your vehi-
cle that were available at the time of going to
press. National variations are possible. Note
that your vehicle may not be equipped with all
of the functions described. This is also the
case for systems and functions relevant to
safety.
i Read the information on qualified specialist
workshops: (Y page 23). Key
Important safety notes
G
WARNING
If children are left unsupervised in the vehicle, they could:
R open doors, thereby endangering other per-
sons or road users
R get out and be struck by oncoming traffic
R operate vehicle equipment and become
trapped, for example
In addition, the children could also set the
vehicle in motion by, for example:
R releasing the parking brake
R shifting the transmission out of park posi-
tion P
R starting the vehicle's drive system
There is a risk of an accident and injury.
When leaving the vehicle, always take the key with you and lock the vehicle. Never leave
children and animals unattended in the vehi-
cle. Keep the keys out of the reach of children. G
WARNING
If you attach heavy or large objects to the key, the key could be unintentionally 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
key. Remove any bulky keyrings before insert-
ing the key into the ignition lock. !
Keep the key away from strong magnetic
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 key: R with electronic devices, e.g. a mobile phone
or another key
R with metallic objects, e.g. coins or metal film
R inside metallic objects, e.g. a metal case
Vehicles with KEYLESS-GO start function: do
not keep the key in the luggage compartment.
Otherwise, the key may not be detected, e.g.
when starting the drive system using the Start/
Stop button.
United Kingdom only: G
WARNING
When the double locks are activated, the
doors can no longer be opened from the
inside. People in the vehicle can no longer get out, e.g. in hazardous situations. There is a
risk of injury.
Therefore, do not leave any people unsuper-
vised in the vehicle, particularly children, eld-
erly people or people in need of special assis-
tance. Do not activate the double lock when
people are in the vehicle.
If the vehicle has been locked from the outside, the double lock function is activated as stand-
ard. It is then not possible to open the doors
from inside the vehicle. You can deactivate the
double lock function by deactivating the interior
motion sensor (Y page 69). The doors can then
be opened from the inside after the vehicle has
been locked from the outside. You can open the rear doors from inside the vehicle if they are not
secured by the child-proof locks (Y page 60).
The anti-theft alarm system is triggered if the
door is opened from the inside. Switch off the
alarm (Y page 68). G
WARNING
If persons (particularly children) are exposed
to heat or cold for a prolonged period, there is a risk of serious or even fatal injuries. Never
leave persons (particularly children) unatten-
ded in the vehicle. Key
71Opening and closing Z

Key functions
:
& Locks the vehicle
; % Unlocks the vehicle
X To unlock centrally: press the%button.
If you do not open the vehicle within approx-
imately 40 seconds of unlocking:
R the vehicle locks again
R protection against theft is reactivated
X To lock: press the &button.
The key centrally locks/unlocks:
R the doors
R the tailgate
R the charge socket flap
When unlocking, the turn signals flash once.
When locking, they flash three times.
When the locator lighting is activated in Audio
20/COMAND Online, it lights up when it is dark
after the vehicle is unlocked with the remote
control (see separate operating instructions).
You can also set an audible signal to confirm
that the vehicle has been locked. The audible
signal can be activated or deactivated using the
on-board computer (Y page 187).KEYLESS-GO
General notes Bear in mind that the drive system can be star-
ted by any of the vehicle occupants if there is a
key in the vehicle.
Locking and unlocking You can start, lock or unlock the vehicle using
KEYLESS-GO. To do this, you need to carry the
key with you. You can combine the KEYLESS-GO functions with the functions of a conventional
key. Unlock the vehicle by using KEYLESS-GO,
for instance, and lock it using the &button
on the key.
The driver's door and the door at which the han- dle is used must both be closed. The key must beoutside the vehicle. When locking or unlocking
with KEYLESS-GO, the distance between the keyand the corresponding door handle must not be
greater than 1 m.
A check which periodically establishes a radio
connection between the vehicle and the key
determines whether a valid key is in the vehicle. This occurs, for example:
R when starting the drive system
R whilst driving
R when the external door handles are touched
R during convenience closing X
To unlock the vehicle: touch the inner sur-
face of the door handle.
X To lock the vehicle: touch sensor surface :
or ;.
Make sure that you do not touch the inner
surface of the door handle.
X Convenience closing feature: touch
recessed sensor surface ;for an extended
period.
For further information on the convenience
closing feature (Y page 83).72
KeyOpening and closing

X
To unlock the tailgate: pull tailgate han-
dle :.
Deactivating and activating If you do not intend to use the vehicle for an
extended period of time, you can deactivate
KEYLESS-GO. The key will then use very little
power, thereby conserving battery power. For
the purposes of activation or deactivation, the
vehicle does not have to be nearby.
X To deactivate: press the&button on the
key twice in rapid succession.
The battery check lamp of the key flashes
twice briefly and lights up once, then KEY-
LESS-GO is deactivated (Y page 74).
X To activate: press any button on the key.
or X Insert the key into the ignition lock.
KEYLESS-GO and all of its associated features
are available again. KEYLESS-GO start function
General notes Bear in mind that the drive system can be star-
ted by any of the vehicle occupants if there is a
key in the vehicle. Changing the settings of the locking
system
You can change the settings of the locking sys-
tem. This means that only the driver's door and
the charge socket flap are unlocked when the
vehicle is unlocked. This is useful if you fre-
quently travel alone.
X To change the setting: press and hold down
the % and& buttons simultaneously
for about six seconds until the battery indica-
tor lamp (Y page 74) flashes twice.
If the setting of the locking system is changed
within the signal range of the vehicle, pressing
the & or% button:
R locks or
R unlocks the vehicle
The key now functions as follows:
X To unlock: press the%button once.
X To unlock centrally: press the%button
twice.
X To lock centrally: press the&button.
The KEYLESS-GO function is changed as fol-
lows:
X To unlock the driver's door: touch the inner
surface of the door handle on the driver's
door.
X To unlock centrally: touch the inner surface
of the door handle on the front-passenger
door or the rear door.
X To lock centrally: touch the outer sensor
surface on one of the door handles.
X To restore the factory settings: press and
hold down the %and& buttons simul-
taneously for approximately six seconds until
the battery check lamp flashes twice
(Y page 74). Emergency key element
General notes If the vehicle can no longer be unlocked with the
key or KEYLESS-GO, use the emergency key ele-
ment.
If you use the emergency key element to unlock
and open the driver's door or the tailgate, the
anti-theft alarm system will be triggered
(Y page 68). Key
73Opening and closing Z

There are several ways to deactivate the alarm:
X To deactivate the alarm with the key: press
the % or& button on the key.
or
X Insert the key into the ignition lock.
or X To deactivate the alarm with KEYLESS-GO:
press the Start/Stop button in the ignition
lock. The key must be in the vehicle.
or
X Lock or unlock the vehicle using KEYLESS-
GO. The key must be outside the vehicle.
If you unlock the vehicle using the emergency
key element, the charge socket flap will not be
unlocked automatically.
Removing the emergency key element X
Push release catch :in the direction of the
arrow and, at the same time, remove emer-
gency key element ;from the key.
Further information about:
R unlocking the driver's door (Y page 80)
R unlocking the luggage compartment
(Y page 81)
R locking the vehicle (Y page 80)
Inserting the emergency key element X
Push emergency key element ;completely
into the key until it engages and release
catch :is back in its basic position. Battery of the key
Important safety notes G
WARNING
Batteries contain toxic and corrosive substan- ces. If batteries are swallowed, it can result in
severe health problems. There is a risk of fatal injury.
Keep batteries out of the reach of children. If
a battery is swallowed, seek medical attention immediately. H
Environmental note Batteries contain pollutants.
It is illegal to dispose of them
with the household rubbish.
They must be collected sep-
arately and disposed of in anenvironmentally responsible
recycling system. Dispose of batteries in an
environmentally responsible
manner. Take discharged
batteries to a qualified spe-
cialist workshop or to a col-
lection point for used batter-
ies.
Mercedes-Benz recommends that you have the
battery replaced at a qualified specialist work-
shop.
Checking the battery X
Press the &or% button.
The battery is working properly if battery
check lamp :lights up briefly. 74
KeyOpening and closing