lock MERCEDES-BENZ A-CLASS HATCHBACK 2012 Owner's Manual

opened from inside the vehicle. When the
vehicle is unlocked, the door can be opened
from the outside.
X To activate: press the child-proof lock
lever up in the direction of arrow :.
X Make sure that the child-proof locks are
working properly.
X To deactivate: press the child-proof lock
lever down in the direction of arrow ;.
Override feature for the rear side win-
dows X
To activate/deactivate: press button:.
If indicator lamp is lit, operation of the rear side windows is disabled. Operation is only
possible using the switches in the driver's
door. If the indicator lamp is off, operation
is possible using the switches in the rear
compartment. Driving safety systems
Driving safety systems overview
In this section, you will find information about the following driving safety systems:
R ABS ( Anti-lock BrakingSystem)
(Y page 61)
R BAS ( Brake Assist System) (Y page 62)
R COLLISION PREVENTION ASSIST (adaptive
Brake Assist and distance warning func-
tion) (Y page 62)
R Adaptive brake lamps (Y page 64)R
ESP ®
(Electronic StabilityProgram)
(Y page 65)
R EBD ( electronic brake force distribution)
(Y page 68)
R ADAPTIVE BRAKE (Y page 69)
R STEER CONTROL (Y page 69) 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 accident nor over-
ride the laws of physics. Driving safety sys-
tems are merely aids designed to assist driv- ing. You are responsible for the distance to
the vehicle in front, for vehicle speed and forbraking in good time. Always adapt your driv- ing style to suit the prevailing road, weather
and traffic conditions and maintain a safe dis-
tance from the vehicle in front. Drive care-
fully.
i The driving safety systems described only
work as effectively as possible when there
is adequate contact between the tyres and
the road surface. Pay particular attention to the information regarding tyres, recom-
mended minimum tyre tread depths etc. inthe "Wheels and tyres" section
(Y page 318).
In wintry driving conditions, always use
winter tyres (M+S tyres) and, if necessary,
snow chains. Only in this way will the driv-
ing safety systems described in this section work as effectively as possible. ABS (Anti-lock Braking System)
Important safety notes i
Observe the "Important safety notes" sec-
tion for driving safety systems (Y page 61). G
WARNING
If ABS is faulty, the wheels could lock when
braking. The steerability and braking charac-
teristics may be severely impaired. Addition- Driving safety systems
61Safety
Z

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.
If ABS is malfunctioning, other systems,
including driving safety systems, will also
become inoperative. Observe the information on the ABS warning lamp (Y page 258) and
display messages which may be shown in the
instrument cluster (Y page 230).
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.
ABS works from a speed of about 8 km/h
upwards, regardless of road-surface condi-
tions. ABS works on slippery surfaces, even
when you only brake gently.
The ! ABS warning lamp in the instrument
cluster lights up when the ignition is switched on. It goes out when the engine is running.
Braking X
If ABS intervenes: continue to depress the
brake pedal with force 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.
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)
i Observe the "Important safety notes" sec-
tion (Y page 61). G
WARNING
If BAS is malfunctioning, the braking distance
in an emergency braking situation is
increased. There is a risk of accident.
In an emergency braking situation, depress
the brake pedal with full force. ABS prevents
the wheels from locking.
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.
The brakes will function as usual once you
release the brake pedal. BAS is deactivated. COLLISION PREVENTION ASSIST
General notes COLLISION PREVENTION ASSIST consists of
the adaptive Brake Assist and the distance
warning signal, which are described in the
following.
Distance warning function Important safety notes
i Observe the "Important safety notes" sec-
tion for driving safety systems (Y page 61). 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. 62
Driving safety systemsSafety

G
WARNING
Adaptive Brake Assist cannot always clearly
identify objects and complex traffic situa-
tions. In these cases, Adaptive Brake Assist
may not intervene. There is a risk of an acci-
dent.
Always pay careful attention to the traffic sit- uation and be ready to brake. G
WARNING
Adaptive Brake Assist does not react:
R to people or animals
R to oncoming vehicles
R to crossing traffic
R to stationary obstacles
R when cornering
As a result, 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.
Adaptive Brake Assist aids you in braking dur-
ing hazardous situations at speeds above
30 km/h and uses the radar sensor system to evaluate the traffic situation.
With the help of a sensor system, adaptive
Brake Assist can detect obstacles that are in the path of your vehicle for an extended
period of time.
Should you approach an obstacle and adap-
tive Brake Assist has detected a risk of colli-
sion, adaptive Brake Assist calculates the
braking force necessary to avoid a collision.
Should 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.
Vehicles with PRE-SAFE ®
:if adaptive Brake
Assist requires particularly high brake pres-
sure, preventative passenger protection
measures (PRE-SAFE ®
) are deployed simul-
taneously.
Up to vehicle speeds of around 250 km/h,
adaptive Brake Assist is capable of reacting to
moving objects that have already been rec-
ognised as such at least once over the period of observation. Adaptive Brake Assist does
not react to stationary obstacles.
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.
In particular, the detection of obstacles can
be impaired if there is:
R dirt on the sensors or anything else cover-
ing the sensors
R snow or heavy rain
R interference by other radar sources
R the possibility of strong radar reflections,
for example, in multi-storey car parks
R a narrow vehicle travelling in front, e.g. a
motorcycle
R a vehicle travelling in front on a different
line
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 slow speeds where there is no visible
damage to the front of the vehicle. Adaptive brake lamps
If you brake sharply from a speed of more
than 50 km/h or if braking is assisted by BAS 64
Driving safety systemsSafety

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 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 stabilise the vehi-
cle 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.
X To deactivate:(Y page 218).
The å ESP®
OFF warning lamp in the
instrument cluster lights up.
X To activate:( Ypage 218).
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 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 cut-
ting action for better traction on loose sur- faces.
R traction control is still activated.
R ESP ®
still provides support when you
brake. ESP
®
trailer stabilisation General notes
If your vehicle/trailer combination begins to
lurch, ESP
®
assists you in this situation. ESP ®
slows the vehicle down by braking and limit-
ing the engine output until the vehicle/trailer combination has stabilised.
Important safety notes G
WARNING
If road and weather conditions are poor,
trailer stabilisation will not be able to prevent the vehicle/trailer combination from swerv-
ing. Trailers with a high centre 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/trailer combination begins to
lurch, you can only stabilise the vehicle/
trailer combination by depressing the brake
firmly.
ESP ®
trailer stabilisation is active above
speeds of about 65 km/h.
ESP ®
trailer stabilisation does not work if
ESP ®
is deactivated or disabled because of a
malfunction. EBD (electronic brake force distribu-
tion)
i Observe the "Important safety notes" sec-
tion for driving safety systems (Y page 61). G
WARNING
If EBD has malfunctioned, the rear wheels can still lock, e.g. under full braking. This increa-
ses the risk of skidding and an accident.
You should therefore adapt your driving style
to the different handling characteristics. Havethe brake system checked at a qualified spe-
cialist workshop. 68
Driving safety systemsSafety

Observe information regarding indicator and
warning lamps (Y page 258) as well as dis-
play messages (Y page 232).
EBD monitors and controls the brake pres-
sure on the rear wheels to improve driving
stability while braking. 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 180) and
hill start assist (Y page 145). For further
information, see Driving tips (Y page 166).STEER CONTROL
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.
If there is an ESP ®
malfunction, you will not
receive any steering support from STEER
CONTROL. Power steering will, however, con-
tinue to function. Anti-theft systems
Immobiliser
The immobiliser prevents your vehicle from
being started without the correct key.
X To activate: remove the key from the igni-
tion lock.
X To deactivate: switch on the ignition.
When leaving the vehicle, always take the key
with you and lock the vehicle. The engine can be started by anyone with a valid key that is
left inside the vehicle.
i The immobiliser is always deactivated
when you start the engine. ATA (Anti-Theft Alarm system)
X
To prime: lock the vehicle with the key.
Indicator lamp :flashes. The alarm sys-
tem is primed after approximately
15 seconds.
X To deactivate: unlock the vehicle with the
key.
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 the vehicle with the emergency key ele-
ment
R a door
R the tailgate
R the bonnet
X To stop the alarm: insert the key into the
ignition lock.
The alarm is switched off.
or X Press the %or& button on the key.
The alarm is switched off.
The alarm is not switched off, even if you
close the open door that has triggered it, for
example. Anti-theft systems
69Safety Z

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
example.
Activating X
Make sure that:
R the doors are closed.
R the tailgate is closed.
Only then is the tow-away protection
primed.
X Lock the vehicle with the key.
Tow-away protection is primed after
approximately 60 seconds.
Deactivating X
Unlock the vehicle with the key.
or X Insert the key into the ignition lock.
Tow-away protection is switched off auto-
matically.
Deactivating X
Remove the key from the ignition lock.
X Press button :.
Indicator lamp ;lights up briefly.
X Lock the vehicle with the key.
Tow-away protection is deactivated. Tow-away protection remains deactivated
until:
R the vehicle is unlocked again
R a door is opened and closed again
R the vehicle is locked again
To prevent a false alarm, deactivate the tow-
away protection if you lock your vehicle and it:
R is being transported
R is being loaded onto a ferry or car trans-
porter, for example
R is parked on a movable surface, e.g. in a
split-level garage Interior motion sensor
Function When the interior motion sensor is primed, a
visual and audible alarm is triggered if move-
ment is detected in the vehicle interior. This
can occur if someone reaches into the vehicle interior, for example.
Activating X
Make sure that:
R the side windows are closed.
R the panorama sliding sunroof is closed.
R there are no objects, e.g. mascots, hang-
ing on the rear-view mirror or on the grab
handles on the roof trim.
This will prevent false alarms.
X Make sure that:
R the doors are closed.
R the panorama sliding sunroof is closed.
R the tailgate is closed.
Only then is the interior motion sensor
primed.
X Lock the vehicle with the key.
The interior motion sensor is primed after
approximately 30 seconds. 70
Anti-theft systemsSafety

Deactivating
X
Unlock the vehicle with the key.
or
X Insert the key into the ignition lock.
The interior motion sensor is switched off
automatically.
Deactivating X
Remove the key from the ignition lock.
X Press button :.
Indicator lamp ;flashes briefly.
X Lock the vehicle with the key.
The interior motion sensor is deactivated.
The interior motion sensor remains deactiva-
ted until:
R the vehicle is unlocked again
R a door is opened and closed again
R the vehicle is locked again
To prevent a false alarm, deactivate the inte-
rior motion sensor if you lock your vehicle
and:
R people or animals remain in the vehicle.
R the panorama sliding sunroof remains
open.
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 80).
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 79). Anti-theft syste
ms
71Safety Z

Useful information
i This Owner's Manual describes all mod-
els, series and optional equipment for your
vehicle that were available at the time of
going to press. National variations are pos- sible. Note that your vehicle may not be
equipped with all of the functions descri-
bed. This is also the case for systems and
functions relevant to safety.
i Read the information on qualified special-
ist workshops: (Y page 24). Key
Important safety notes
G
WARNING
If children are left unsupervised in the vehicle, they could:
R open the doors, thus endangering other
people or road users.
R get out and disrupt traffic.
R operate the vehicle's equipment.
Additionally, children could set the vehicle in
motion if, for example, they:
R release the parking brake.
R shift the automatic transmission out of
parking position P.
R shift the manual transmission into neutral.
R start the engine.
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 or animals unattended in the vehicle.Always keep the key out of reach of children. 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. 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 func-
tion could be affected.
Strong magnetic fields can occur in the
vicinity 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
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 with the key,
then the double lock function is activated as
standard. You can deactivate the double lock
function by deactivating the interior motion
sensor (Y page 70). The doors can then be
opened from the inside after the vehicle has
been locked from the outside. The anti-theft
alarm system is triggered if the door is
opened from the inside. Switch off the alarm
(Y page 69). 74
KeyOpening and closing

Key functions
:
& To lock the vehicle
; % To unlock the vehicle
X To unlock centrally: press button;.
If you do not open the vehicle within approx-
imately 40 seconds of unlocking:
R the vehicle is locked again.
R the anti-theft system is primed again.
X To lock centrally: press button:.
The key centrally locks/unlocks: R the doors
R the tailgate
R the fuel filler flap
When unlocking, the turn signals flash once.
When locking, they flash three times.
i When it is dark, the surround lighting also
comes on if it is activated in the on-board
computer (Y page 222).
i You can also set an audible signal to con-
firm that the vehicle has been locked. The
audible signal can be activated and deacti-
vated using the on-board computer
(Y page 223). Changing the settings of the locking
system
You can change the settings of the locking
system. This means that only the driver's door
and the fuel filler flap are unlocked when the
vehicle is unlocked. This is useful if you fre-
quently travel on your own.
X To change the setting: press and hold
down the %and& buttons simulta-
neously for approximately six seconds until
battery check lamp (Y page 76) flashes
twice.
i If the setting of the locking system is
changed within the signal range of the vehi- cle, pressing the &or% button:
R locks or
R unlocks the vehicle
The key now functions as follows:
X To unlock the driver's door: press the
% button once.
X To unlock centrally: press the%but-
ton twice.
X To lock centrally: press the&button.
X To restore the factory settings: press
and hold down the %and& buttons
simultaneously for approximately six sec-
onds until the battery check lamp flashes
twice (Y page 76). Emergency key element
General notes If the vehicle can no longer be unlocked with
the key, use the emergency key element.
If you use the emergency key element to
unlock and open the driver's door, the anti-
theft alarm system will be triggered
(Y page 69).
There are several ways to turn off the alarm:
X Press the %or& button on the key.
or X Insert the key into the ignition lock. Key
75Opening and closing Z

If you unlock the vehicle using the emergency
key element, the fuel filler flap will not be
unlocked automatically.
X To unlock the fuel filler flap: insert the
key into the ignition lock.
Removing the emergency key element X
Push release catch :in the direction of
the arrow and at the same time, remove
emergency key element ;from the key. 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 an environmentally 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 batteries replaced at a qualified specialist workshop.
Checking the battery X
Press the &or% button.
The battery is working properly if battery
check lamp :lights up briefly.
The battery is discharged if battery check
lamp :does not light up briefly.
X Replace the battery (Y page 76).
i If the key battery is checked within the
signal reception range of the vehicle, press- ing the &or% button:
R locks or
R unlocks the vehicle
i You can obtain a battery from any quali-
fied specialist workshop.
Replacing the battery You require a CR 2025 3 V cell battery.76
KeyOpening and closing