2015 MERCEDES-BENZ B-CLASS HATCHBACK Owners Manual

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

The battery is discharged if battery check
lamp :does not light up briefly.
X Replace the battery (Y page 75).
i If the key battery is checked within the sig-
nal reception range of the vehicle, pressing
the & or% button:
R locks or
R unlocks the vehicle
i You can obtain a battery from any qualified
specialist workshop.
Replacing the battery You require a CR 2025 3 V cell battery.
X Take the emergency key element out of the
key (Y page 73). X
Press emergency key element ;into the
opening in the key 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 key 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 contamination.
X Insert the front tabs of battery tray cover :
and then press to close it.
X Insert emergency key element into the key
(Y page 74).
X Check the function of all key buttons on the
vehicle. Key
75Opening and closing Z

Problems with the key
Problem
Possible causes/consequences and
M
MSolutions You cannot lock or
unlock the vehicle using
the key. The key battery is discharged or nearly discharged.
X Vehicles without KEYLESS-GO or KEYLESS-GO start function:
try again to lock/unlock the vehicle using the remote control func-
tion of the key. Point the tip of the key at the driver's door handle
from close range and press the %or& button.
If this does not work:
X Check the key battery (Y page 74) and replace it if necessary
(Y page 75).
X Lock (Y page 80) or unlock (Y page 80) the vehicle using the
emergency key element. There is interference from a powerful source of radio waves.
X Vehicles without KEYLESS-GO or KEYLESS-GO start function:
try again to lock/unlock the vehicle using the remote control func-
tion of the key. Point the tip of the key at the driver's door handle
from close range and press the %or& button.
If this does not work:
X Lock (Y page 80) or unlock (Y page 80) the vehicle using the
emergency key element. The key is faulty.
X Lock (Y page 80) or unlock (Y page 80) the vehicle using the
emergency key element.
X Have the key checked at a qualified specialist workshop. You can no longer lock or
unlock the vehicle using
KEYLESS-GO. The key battery is discharged or nearly discharged.
X Check the key battery (Y page 74) and replace it if necessary
(Y page 75).
If this does not work: X Lock (Y page 80) or unlock (Y page 80) the vehicle using the
emergency key element. There is interference from a powerful source of radio waves.
X Lock (Y page 80) or unlock (Y page 80) the vehicle using the
emergency key element. 76
KeyOpening and closing

Problem
Possible causes/consequences and
M
MSolutions There is a fault with KEYLESS-GO.
X Lock/unlock the vehicle using the remote control function of the
key.
X Have the vehicle and key checked at a qualified specialist work-
shop.
If the vehicle can also not be locked/unlocked using the remote con-
trol function:
X Lock (Y page 80) or unlock (Y page 80) the vehicle using the
emergency key element.
X Have the vehicle and key checked at a qualified specialist work-
shop. The drive system cannot
be started using the key. the on-board voltage is too low
X Switch off non-essential consumers, e.g. seat heating or interior
lighting, and try to start the drive system again.
If this does not work: X Check the 12 V battery and charge it if necessary (Y page 256).
or
X Check the high-voltage battery and charge it if necessary
(Y page 135).
or
X Jump-start the vehicle (Y page 258).
or
X Consult a qualified specialist workshop. The drive system cannot
be started using the
Start/Stop button. The
key is in the vehicle. The vehicle is locked.
X Unlock the vehicle and try to start the vehicle again. The key battery is discharged or nearly discharged.
X Check the key battery (Y page 74) and replace it if necessary
(Y page 75).
If this does not work: X Start your vehicle with the key in the ignition lock. There is interference from a powerful source of radio waves.
X Start your vehicle with the key in the ignition lock. You have lost a key. X
Have the key deactivated at a qualified specialist workshop.
X Report the loss immediately to the vehicle insurers.
X If necessary, have the locks changed as well. You have lost the emer-
gency key element. X
Report the loss immediately to the vehicle insurers.
X If necessary, have the locks changed as well. Key
77Opening and closing Z