lights MERCEDES-BENZ A-CLASS HATCHBACK 2012 User Guide

SRS (Supplemental Restraint System)
Introduction Supplemental Restraint System (SRS) with:
R The 6 SRS warning lamp
R Airbags
R Airbag control unit (with crash sensors)
R Belt tensioners for the front seat belts and
the outer seat belts in the rear
R Seat belt force limiters for the front seat
belts and the outer seat belts in the rear
SRS reduces the risk of occupants coming
into contact with parts of the vehicle's interior
in the event of an accident. It can also reduce
the forces to which occupants are subjected
during an accident.
SRS warning lamp G
WARNING
If SRS is malfunctioning, individual systems
may be triggered unintentionally or might not be triggered in the event of an accident with ahigh rate of vehicle deceleration.
A malfunction has occurred if:
R the 6 SRS warning lamp does not light
up when the ignition is switched on.
R the engine is running and the 6SRS
warning lamp does not go out after a few
seconds.
R the engine is running and the 6SRS
warning lamp lights up again.
In this case, have SRS checked immediately at
a qualified specialist workshop.
The 6 SRS warning lamp in the instrument
cluster lights up when the ignition is switched on. It goes out no later than a few seconds
after the engine is started.
SRS functions are checked regularly when the
ignition is switched on or the engine is run-
ning. Therefore, malfunctions can be detec-
ted in good time. Triggering of belt tensioners and air-
bags During the first stage of a collision, the airbag
control unit evaluates important physical
data relating to vehicle deceleration or accel-
eration, such as:
R duration
R direction
R magnitude
Based on the evaluation of this data, the air-
bag control unit pre-emptively triggers the
belt tensioners in the first stage.
If there is an even higher rate of vehicle decel- eration or acceleration in a longitudinal direc-tion, the front airbags are also deployed.
Your vehicle has adaptive, two-stage front air-
bags. The airbag control unit evaluates vehi-
cle deceleration or acceleration in the event
of a collision. In the first deployment stage,
the front airbag is filled with enough propel-
lant gas to reduce the risk of injuries. The
front airbag is fully deployed if a second
deployment threshold is reached within a few milliseconds.
The belt tensioner and airbag triggering
thresholds are variable and are adapted to the
detected rate of deceleration or acceleration
of the vehicle. This process is pre-emptive in
nature. The triggering process must take
place in good time at the start of the collision.
The rate of vehicle deceleration or accelera-
tion and the direction of the force are essen-
tially determined by:
R the distribution of forces during the colli-
sion
R the collision angle
R the deformation characteristics of the vehi-
cle
R the characteristics of the object with which
the vehicle has collided
Factors which can only be seen and measured
after a collision has occurred do not play a
decisive role in the deployment of an airbag, Occupant safety
41Safety Z

R
do not lean forwards, e.g. over the cover of
the driver's/front-passenger front airbag,
particularly when the vehicle is in motion.
R do not put your feet on the dashboard.
R only hold the steering wheel on the outside.
This allows the airbag to be fully deployed.
You could be injured if the airbag is
deployed and you are holding the inside of
the steering wheel.
R do not lean on the doors from inside the
vehicle.
R make sure that there are no people, ani-
mals or objects between the vehicle occu-
pants and the area where the airbags are
deployed.
R do not place any objects between the seat
backrest and the door.
R do not hang any hard objects, e.g. coat
hangers, on the grab handles or coat hooks.
R do not attach accessories, e.g. cup holders,
to the doors.
It is not possible to rule out a risk of injury
being caused by an airbag, due to the high
speed at which the airbag must be deployed. G
WARNING
Airbag functionality can only be assured if the following parts are not covered and no badgesor stickers are attached to them:
R padded steering wheel boss
R kneebag cover below the steering column
R front-passenger airbag cover
R outer side of front seat bolsters
R side trim next to the rear seat backrest
R roof frame cover between the front A-pillar
and the C-pillar in the rear compartment G
WARNING
When an airbag deploys, a small amount of
powder is released. The powder may cause
short-term breathing difficulties to persons
suffering from asthma or other pulmonary
conditions. In order to prevent potential breathing diffi-
culties, you should leave the vehicle as soon
as it is safe to do so. You can also open the
window to allow fresh air to enter the vehicle
interior. The powder does not constitute a
health hazard and does not indicate that there
is a fire in the vehicle. G
WARNING
The airbag parts are hot after the airbag has
been deployed. Do not touch them as you
could burn yourself.
Have the airbags replaced at a qualified spe-
cialist workshop. Otherwise, occupants are
not protected by the airbags in the event of
another accident.
Airbag deployment slows down and restricts
the movement of the vehicle occupant.
If the airbags are deployed, you will hear a
bang and a small amount of powder may also
be released. Only in rare cases will the bang
affect your hearing. The powder that is
released generally does not constitute a
health hazard. The 6SRS warning lamp
lights up.
The airbag installation locations are identified
by the AIRBAG symbol.
Front airbags !
Do not place heavy objects on the front-
passenger seat. The system may then
detect that the seat is occupied and if there
is an accident, the restraint systems on the front-passenger side could be deployed.
Have restraint systems that have been trig-
gered replaced. Occupant safety
43Safety Z

The belt strap is tightened slightly when:
R you engage the belt tongue in the belt
buckle and you then turn the key to position
2 in the ignition lock.
R the key is in position 2in the ignition lock
and you then engage the belt tongue in the buckle.
The seat-belt adjustment will apply a certain
tightening force if any slack is detected
between the occupant and the seat belt. Do
not hold on to the seat belt tightly while it is
adjusting. You can switch the seat-belt
adjustment on and off in the on-board com-
puter (Y page 225).
The seat-belt adjustment is an integral part of
the PRE-SAFE ®
convenience function. More
information about PRE-SAFE ®
can be found in
the "PRE-SAFE ®
(preventative occupant pro-
tection)" section (Y page 45).
Belt height adjustment You can adjust the belt height for the front
seats. Adjust the belt to a height that allows
the upper part of the seat belt to be routed
across the centre of your shoulder.
X To raise: slide the belt sash guide upwards.
The belt sash guide engages in various posi-
tions.
X To lower: press and hold belt sash guide
release :.
X Slide the belt sash guide downwards.
X Let go of belt sash guide release :and
make sure that the belt sash guide has
engaged. Releasing the seat belts !
Make sure that the seat belt is fully rolled
up. Otherwise, the seat belt or belt tongue
will be trapped in the door or in the seat
mechanism. This could damage the door,
the door trim panel and the seat belt. Dam- aged seat belts can no longer fulfil their
protective function and must be replaced.
Visit a qualified specialist workshop. X
Press release button ?on belt buckle =.
X Guide belt tongue ;back to belt sash
guide :.
Belt warning for the driver and front
passenger The
7 seat belt warning lamp in the instru-
ment cluster is a reminder for all occupants to
fasten their seat belts. It may light up contin- uously or flash. In addition, a warning tone
may sound.
The 7 seat belt warning lamp goes out and
the warning tone ceases when the driver and
the front passenger have fastened their seat
belt.
For certain countries only: regardless of
whether the driver and the front passenger
have fastened their seat belts, the 7seat
belt warning lamp lights up for six seconds
after the engine is started. It then goes out if 48
Occupant safetySafety

ates or accelerates rapidly in a lateral direc-
tion
R in certain situations where the vehicle over-
turns and the system determines that it can
provide additional protection
If the airbags are deployed, you will hear a
bang, and a small amount of powder may also be released. Only in rare cases will the bang
affect your hearing. The powder that is
released generally does not constitute a
health hazard. The 6SRS warning lamp
lights up.
If the seat belt is also fitted with a belt force
limiter and this is triggered, the force exerted by the seat belt on the vehicle occupant is
reduced.
The belt force limiters on the front seats are
synchronised with the front airbags, which
take on a part of the deceleration force. This
results in the load being distributed over a
greater area. Children in the vehicle
Child restraint systems
Important safety notes G
WARNING
To reduce the risk of serious or even fatal
injury to the child in the event of a sudden
change in direction, braking or an accident:
R children less than 1.50 m tall and under
twelve years of age must always be secured
in special child restraint systems on a suit- able vehicle seat. This is necessary
because the seat belts are not designed for
children.
R Do not drive with a child secured in a rear-
ward-facing child restraint system on the
front-passenger seat. Exception: if the vehi-
cle is equipped with automatic child seat
recognition on the front-passenger seat
and the child is secured in a child restraint
system with transponders for automatic
child seat recognition R
if you secure a forward-facing child
restraint system to the front-passenger
seat, you must move the front-passenger
seat as far back as possible.
R children must never travel sitting on the lap
of another occupant. Due to the forces
which occur in the event of a sudden
change of direction, heavy braking or an
accident, it would not be possible to
restrain the child. The child could be thrown against parts of the vehicle interior and be
seriously or even fatally injured. G
WARNING
The child restraint system cannot perform its protective function if it is not correctly fitted
to a suitable vehicle seat. The child cannot berestrained in the event of an accident, heavy
braking or sudden changes of direction. The
child could be seriously or even fatally injured.
For this reason, when fitting a child restraint
system, observe the manufacturer's installa-
tion instructions and the correct use of the
child restraint system.
Child restraint systems should be fitted to the rear seats. Children are generally better pro-
tected there.
The entire base of the child restraint system
must always rest on the seat cushion. There-
fore, never place objects, e.g. a cushion,
under the child restraint system.
Only use child restraint systems with the orig-
inal cover designed for them. Only replace
damaged covers with genuine Mercedes-Benz
covers.
We recommend the use of child restraint sys- tems which have been approved for
Mercedes-Benz vehicles. G
WARNING
Do not leave children unsupervised in the
vehicle, even if they are secured in a child
restraint system. They could injure them-
selves on parts of the vehicle. They could also
be seriously or even fatally injured by pro-
longed exposure to extreme heat or cold. 50
Children in the vehicleSafety

Warning notice on the front-passenger sun visor
Warning symbol for a rearward-facing child
restraint system
Do not use a rearward-facing child restraint
system on a seat that is protected by an air-
bag installed in front of it.
Automatic child seat recognition on the front-passenger seat G
WARNING
If the 4 PASSENGER AIRBAG OFF indica-
tor lamp does not light up when the child
restraint system is fitted, the front-passenger airbag has not been disabled. If the front-
passenger airbag deploys, the child could be
seriously or even fatally injured.
Proceed as follows:
R do not use a rearward-facing child restraint
system on the front-passenger seat.
R fit a rearward-facing child restraint system
on a suitable rear seat.
or R
only use a forward-facing child restraint
system on the front-passenger seat and
move the front-passenger seat to the rear-
most position.
R have the automatic child seat recognition
checked at a qualified specialist workshop.
To ensure that the automatic child seat rec-
ognition on the front-passenger seat func-
tions/communicates correctly, never place
objects, e.g. a cushion, under the child
restraint system. The entire base of the child
restraint system must always rest on the seat
cushion. An incorrectly fitted child restraint
system cannot perform its intended protec-
tive function in the event of an accident, and
could lead to injuries. G
WARNING
Do not place electronic devices on the front-
passenger seat, e.g.:
R laptops, when switched on
R mobile phones
R cards with transponders, e.g. ski passes or
access cards
Signals from electronic equipment can cause
interference in the automatic child seat rec-
ognition sensor system. This can lead to a
system malfunction. This may cause the 4
PASSENGER AIRBAG OFF indicator lamp to
light up without there being a child seat with
transponders for automatic child seat recog-
nition fitted. The front-passenger airbag will
not then deploy during an accident. It is also
possible that the 6SRS warning lamp
lights up and/or the 4PASSENGER AIR-
BAG OFF indicator lamp does not light up
briefly when you turn the key in the ignition
lock to position 2.52
Children in the vehicleSafety

If the front-passenger seat of your vehicle
does not have automatic child seat recogni-
tion, this is indicated by a special sticker. The sticker is affixed to the side of the dashboard
on the front-passenger side. The sticker is
visible when you open the front-passenger
door.
Vehicles without automatic child seat recog-
nition on the front-passenger seat: if you turn
the key to position 2 in the ignition lock, the
45 indicator lamp lights up briefly but
has no function. It does not indicate that there is automatic child seat recognition on the
front-passenger seat. The sensor system for child restraint systems
in the front-passenger seat detects whether a special Mercedes-Benz child seat with a
transponder for automatic child seat recog-
nition has been fitted. In this case, 45
indicator lamp :lights up. The front-
passenger front airbag is disabled. i
If the front-passenger front airbag is dis-
abled by the automatic child seat recogni-
tion, the following remain enabled on the
front-passenger side:
R the sidebag
R the windowbag
R the belt tensioner
ISOFIX child seat securing system for
the rear seats G
WARNING
A child restraint system secured by the ISOFIX child seat securing system does not provide
sufficient protection for children weighing
more than 22 kg. For this reason, do not
secure children weighing more than 22 kg in achild restraint system secured by the ISOFIX
child seat securing system. If the child weighsmore than 22 kg, secure the child restraint
system with the vehicle seat belt as well. In
addition, when fitting a child restraint system, be sure to observe the manufacturer's instal-
lation instructions and the instructions for
correct use of the child restraint system. G
WARNING
The child restraint system cannot perform its protective function if it is not correctly fitted
to a suitable vehicle seat. The child cannot berestrained in the event of an accident, heavy
braking or sudden changes of direction. The
child could be seriously or even fatally injured.
For this reason, when fitting a child restraint
system, be sure to observe the manufactur-
er's installation instructions and the instruc-
tions for correct use of the child restraint sys-
tem.
For safety reasons, when installing child
restraint systems on the rear seats, only use
child restraint systems with the ISOFIX child
seat securing system, which are specially tes- ted and approved for Mercedes-Benz vehi-
cles.
An incorrectly fitted child restraint system
could come loose and seriously or even fatally Children in the vehicle
53Safety
Z

Problems with automatic child seat recognition
Problem
Possible causes/consequences and
M
MSolutions The
45 indica-
tor lamp on the centre
console is lit. A special Mercedes-Benz child restraint system with a trans-
ponder for automatic child seat recognition has been fitted to the
front-passenger seat. The front-passenger front airbag has there- fore been disabled as desired. G
WARNING
There is no child restraint system fitted to the front-passenger
seat. Automatic child seat recognition is malfunctioning.
It is also possible that the 6SRS warning lamp lights up and/
or the 45 PASSENGER AIRBAG OFF indicator lamp does
not light up briefly when you switch the ignition on.
There is a risk of injury.
X Remove electronic equipment from the front-passenger seat,
e.g.:
R Laptop
R Mobile phone
R Cards with transponders, such as ski passes or access cards
If the 45 indicator lamp remains lit:
X Visit a qualified specialist workshop. Suitable positioning of the child restraint systems
Key to the letters used in the table:
XS
eat which is unsuitable for children in this weight category.
US uitable for child restraint systems in the "Universal" category that are approved for use
in this weight category.
UF Suitable for forward-facing child restraint systems that belong to the "Universal" category and are approved for use in this weight category.
LS uitable for child restraint systems as recommended, see the following table of "Recom-
mended child restraint systems" (Y page 58).56
Children in the vehicleSafety

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

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; do not rely on the distance warning
function alone.
Function X To activate/deactivate: activate or deac-
tivate the distance warning function in the
on-board computer (Y page 218).
Vehicles with a black and white multi-
function display: when the distance warning
function is activated, the Äsymbol
appears in the status overview in the multi-
function display.
Vehicles with a colour multifunction dis-
play: when the distance warning function is
deactivated, the æsymbol appears in the
assistance graphics in the multifunction dis-
play.
The distance warning function can help you to
minimise 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. With- out your intervention, the distance warning
function cannot prevent a collision.
The distance warning function issues a warn- ing at speeds:
R of around 30 km/h or more, if, over several
seconds, the distance maintained to the
vehicle travelling in front is insufficient. The · distance warning lamp then lights up
in the instrument cluster.
R of around 7 km/h or higher, if you very
quickly 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 70 km/h, the dis-
tance warning function can also react to sta-
tionary 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 alert you both visually and
acoustically.
In particular, the detection of obstacles can
be impaired in the case of:
R dirt on the sensors or obscured sensors
R snow or heavy rain
R interference by other radar sources
R 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 Assist i
Observe the "Important safety notes" sec-
tion for driving safety systems (Y page 61). Driving safety systems
63Safety Z

or adaptive Brake Assist, the brake lamps
flash rapidly. In this way, traffic travelling
behind you is warned in an even more notice-
able manner.
If you brake sharply from a speed of more
than 70 km/ht o a standstill, the hazard warn-
ing lamps are activated automatically. If the
brakes are applied again, the brake lamps
light up continuously. 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 switch button (Y page 108).
i Adaptive brake lamps are only available in
certain countries. 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 vehicle 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/4ETS (Electronic Traction System) i
Observe the "Important safety notes" sec-
tion (Y page 61).
ETS/4ETS traction control is part of ESP ®
.
ETS brakes the drive wheels individually 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 transferred to
the wheel or wheels with traction. ETS remains active when you deactivate
ESP
®
.
Important safety notes 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 testing the electric parking brake
on a braking dynamometer, switch off the
ignition. Application of the brakes by ESP ®
may otherwise destroy the brake system.
! Vehicles with 4MATIC: switch off the igni-
tion when the electric parking brake is
being tested using a dynamometer.
Application of the brakes by ESP ®
may oth-
erwise destroy the brake system.
! Vehicles with 4MATIC: function or per-
formance tests may only be carried out on
a 2-axle dynamometer. Before operating
the vehicle on such a dynamometer, please
consult a qualified specialist workshop.
You could otherwise damage the drive train
or the brake system.
! Do not tow vehicles with 4MATIC with the
front or rear axle raised.
Vehicles without 4MATIC: when towing your
vehicle with the front axle raised, it is impor-
tant that you observe the notes on
ESP ®
(Y page 312).
Vehicles with 4MATIC: when towing your
vehicle with both axles on the ground, it is
important that you observe the notes on
ESP ®
(Y page 312).
ESP ®
is deactivated if the åESP®
OFF
warning lamp in the instrument cluster lights up continuously when the engine is running. Driving safety systems
65Safety Z