MERCEDES-BENZ B-CLASS HATCHBACK 2011 Service Manual

Useful information
i This Owner's Manual describes all models
and all standard and optional equipment
available to your vehicle at the time of pub-
lication of the Owner's Manual. Country-
specific deviations are possible. Please
note that your vehicle may not be equipped
with all features described. This also
applies to safety-relevan tsystems and
functions.
i Please read the information on qualified
specialist workshops (Y page 22).Occupant safety
Important safety notes
G
WARNING
If service wor kis not carried out correctly, the
operating safety of your vehicle may be affec-
ted. This could cause you to lose control of
your vehicle and cause an accident. More-
over, the safety systems may no longer be
able to protect you or others as they are
designed to do.
Always have service work carried out at a
qualified specialist workshop. G
WARNING
Modifications to or work performed incor-
rectly on the following parts can result in the
restraint systems not functioning as intended:
R the restraint system, consisting of seat
belts and their anchorage points, belt ten-
sioners, belt force limiters and airbags
R the wiring
R networked electronic systems
Airbags and belt tensioners could fail to
deploy or be triggered in an accident despite
the deceleration force being sufficient to trig-
ger the systems, or could be triggered unin-
tentionally. For this reason, never make any
modifications to the restraint systems. Therefore, you must not tamper with elec-
tronic components or their software.
The seat belts, together with SRS (Supple-
mental Restraint System), are complemen-
tary, co-ordinated restraint systems
(Y page 39). They reduce the risk of injury
in specific, pre-defined types of accident sit-
uations and thereby increase occupant
safety. However, seat belts and airbags gen-
erally do not protect against objects pene-
trating the vehicle from the outside.
To ensure that the restraint systems can
deliver their full potential protection, make
sure that:
R the seat and head restraint are adjusted
properly (Y page 86).
R the seat belt has been fastened properly
(Y page 45).
R the airbags can inflate unrestricted if
deployed (Y page 40).
R the steering wheel is adjusted properly
(Y page 91).
R the restraint systems have not been modi-
fied.
An airbag increases the protection of vehicle
occupants wearing a seat belt. However, air-
bags are only an additional restraint system
which complements, but does not replace,
the seat belt. All vehicle occupants must wear
their seat belt correctly at all times, even if
the vehicle is equipped with airbags. The air-
bags are not deployed in all types of acci-
dents. For example, if the protective capacity
of correctly fastened seat belts is not
increased by deploying the airbags, the air-
bags will not deploy.
Airbag deployment only provides increased
protection if the seat belt is worn correctly.
The seat belt helps, firstly, to keep the vehicle
occupant in the best position in relation to the
airbag. Secondly, in a head-on collision, for
example, the seat belt prevents the vehicle
occupant from being propelledt owards the
point of impact. 38
Occupant safetySafety

SRS (Supplemental Restraint System)
Introduction SRS consists of:
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 the vehicle's interior in the
event of an accident. It can also reduce the
forces to which occupants are subjected dur-
ing 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
a high 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.
SRS functions are checked regularly when
you switch on the ignition and when the
engine is running. Therefore, malfunctions
can be detected in good time.
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. Triggering of belt tensioners, belt force
limiters and airbags 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.
i The front belt tensioners can only be trig-
gered if the seat belt tongues on the front
seats are correctly engaged in the seat belt
buckles.
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 a portion of the
available propellant gas in order to reduce the
risk of injuries. If, within a few milliseconds,
the airbag control unit detects that the vehi-
cle is accelerating or decelerating at a greater
rate than originally anticipated, the front air-
bag is then filled with the maximum amount
of propellant gas.
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.
i Not all airbags are deployed in an acci-
dent. The different airbag systems work
independently of each other. Occupant safety
39Safety Z

How the airbag system works is deter-
mined by predicting the severity of the acci-
dent, especially vehicle deceleration or
acceleration, and the type of accident:
R
head-on collision
R side impact
The rate of vehicle deceleration or accelera-
tion and the directio nofthe 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,
nor do they provide an indication of airbag
deployment.
The vehicle may be deformed significantly,
e.g. the bonnet or the wing, without an airbag
being deployed. This is the case if only parts
which are relatively easily deformed are affec-
ted and the rate of deceleration is not high.
Conversely, airbags may be deployed even
though the vehicle suffers only minor defor-
mation. This is the case if, for example, very
rigid vehicle parts such as longitudinal body
members are hit, and sufficient deceleration
occurs as a result. Airbags
Important safety notes G
WARNING
Airbags provide additional protection; they
are not, however, a substitute for seat belts. Observe the following notes to reduce the risk
of serious or even fatal injury caused by airbag
deployment:
R
all vehicle occupants –inparticular, preg-
nant women – must wear their seat belt
correctly at all times and lean back against
the backrest, which should be positioned
as close to the vertical as possible. The
head restraint must support the back of the
head at about eye level.
R always secure childre nless than
1.50mt all or unde r12years of age in suit-
able child restraint systems.
R all vehicle occupants must select a seat
position that is as far away from the airbag
as possible. The driver's seat position must
allow the vehicle to be driven safely. The
driver's chest should be as far away from
the centre of the driver's airbag cover as
possible.
R move the front-passenger seat as far back
as possible. This is especially important if
you have secured a child in a child restraint
system on the front-passenger seat.
R vehicle occupants –inparticular, children
–m ust no tlean their heads into the area of
the window in which the sidebag/window-
bag is deployed.
R rearward-facing child restraint systems
must not be fitted to the front-passenger
seat unless the front-passenger airbag has
been disabled. On the front-passenger
seat, the front-passenger airbag is disabled
if a child restraint system with a trans-
ponder for automatic child seat recognition
is fitted to the front-passenger seat in a
vehicle equipped with automatic child seat
recognition. The 4PASSENGER AIRBAG
OFF indicator lamp must be continuously
lit.
If the front-passenger seat of your vehicle
does not have automatic child seat recog-
nition, or your rearward-facing child
restraint system does not have automatic
child seat recognition, children must be
secured in a child restraint system on a 40
Occupant safetySafety

suitable seat in the rear. 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 possi-
ble.
R make sure there are no heavy or sharp-
edged objects in the pockets of clothing.
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, for example,
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 badges
or 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
As mall amount of powder is released when
an airbag is deployed. The powder could
cause short-term breathing difficulties in peo-
ple with asthma or other respiratory prob-
lems.
In order to prevent breathing difficulties, 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 interior. The pow-
der does not constitute ahealth 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, com-
plementing the restraint of the seat belt.
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
detec tthat 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
41Safety Z

The fronta
irbags increase protection for the
driver's and front-passenger's head and
chest. Driver's airbag
:deploys in front of the
steering wheel; front-passenger front air-
bag ;deploys in front of and above the glove
compartment.
They are deployed:
R at the start of an accident with a high rate
of vehicle acceleration or deceleration in a
longitudinal direction
R if the system determines that airbag
deploymen tcan offer additional protection
to that provided by the seat belt
R depending on whether the seat belt is being
used
R independently of other airbag sinthe vehi-
cle
If the vehicle overturns, the front airbags are
generally not deployed unless the system
detects high vehicle deceleration in a longi-
tudinal direction.
Front-passenger airbag ;is only activated if
the system detects that the front-passenger
seat is occupied. The PASSENGER AIRBAG
OFF indicator lamp 4on the centre con-
sole is not lit (Y page 49). This means that
a child restraint system without automatic
child seat recognition has been fitted to the
front-passenger seat, or a child restraint sys-
tem with automatic child seat recognition has
been fitted incorrectly. Driver's kneebag
Driver's kneebag
:is always deployed along
with the driver's airbag and inflates under-
neath the steering column.
Driver's kneebag :increases the driver's
protection against:
R knee injuries
R thigh injuries
R lower leg injuries
Rear sidebags G
WARNING
If you wish to use seat covers, Mercedes-Benz
recommends that, for safety reasons, you
only use seat covers that have been approved
for Mercedes-Ben zvehicles.
The seat covers must have a special tear seam
for sidebags. Otherwise, the sidebags cannot
deploy correctly and would fail to provide the
intended protection in the event of an acci-
dent. Appropriate seat covers can be
obtained, for example, from a Mercedes-Benz
Service Centre.
When deployed, the sidebags offer additional
protection for the thorax of the vehicle occu-
pants on the side of the vehicle on which the
impact occurs .However, they do not protect
the:
R head
R neck
R arms 42
Occupant safetySafety

Front sidebags
:and rea rsidebags ;
deploy nex tto the outer seat cushions.
They are deployed:
R on the side on which an impact occurs
R at the start of an accident with a high rate
of lateral vehicle deceleration or accelera-
tion, e.g. in a side impact
R independently of the use of the seat belt
R independently of the front airbags
R independently of the belt tensioners
Windowbags The windowbags enhance the level of protec-
tion for the head (but not chest or arms), of
the vehicle occupants on the side of the vehi-
cle on which the impact occurs.
The windowbags are integrated into the side
of the roof frame and deployed in the area
from the A-pillar to the C-pillar. Windowbags
:are deployed:
R on the side on which an impact occurs
R at the start of an accident with a high rate
of lateral vehicle deceleration or accelera-
tion, e.g. in a side impact
R regardless of whether the front-passenger
seat is occupied
R independently of the use of the seat belt
R independently of the front airbags PRE-SAFE
®
(preventative occupant
protection)
! Make sure that there are no objects in the
footwell or behind the seats when moving
the seat back. There is a risk that the seats
and/or the objects could be damaged.
PRE-SAFE ®
takes pre-emptive measures to
protec toccupants in certain hazardous sit-
uations.
PRE-SAFE ®
intervenes:
R in emergency braking situations, e.g. if BAS
is activated or for vehicles with DISTRONIC
PLUS, BAS PLUS intervenes powerfully
R if the radar sensor system detects an immi-
nent danger of collisio nincertain situa-
tions (on vehicles with DISTRONIC PLUS)
R in critical driving situations, e.g. when phys-
ical limits are exceed and the vehicle under-
steers or oversteers severely
PRE-SAFE ®
takes the following measures
depending on the hazardous situation detec-
ted:
R the fron tseat belts are pre-tensioned.
R it improves the seat position if, under acci-
dent conditions, the passenger seat is in an
unfavourable position.
R if the vehicle skids, the panorama sliding
sunroof and the side windows are closed so
that only a small gap remains.
If the hazardous situation passes without
resulting in an accident, PRE-SAFE ®
slackens Occupant safety
43Safety Z

the belt pretensioning
.All settings made by
PRE-SAFE ®
can then be reversed.
If the seat belts are not released:
X Move the backrest or seat back slightly, but
only when the vehicle is stationary.
The belt pretensioning is reduced and the
locking mechanis mis released.
More information abouts eat-belt adjust-
ment ,aconvenience function integrated into
PRE-SAFE ®
, can be found in the "Seat-belt
adjustment" section (Y page 45).Seat belts
Important safety notes G
WARNING
A seat belt which is not worn correctly, or
which has not been engaged in the seat belt
buckle correctly, cannot provide the intended
level of protection. Under certain circumstan-
ces, this could cause severe or even fatal inju-
ries in the event of an accident.
Therefore, make sure that all occupants —in
particular, pregnan twomen —wear their seat
belts correctly at all times.
R The seat belt must fit snugly on your body
and must not be twisted.Therefore, avoid
wearing bulky clothing, e.g. a winter coat.
The shoulder section of the belt must be
routed across the centre of your shoulder
—onn o account across your neck or under
your arm —and pulled tight against your
uppe rbody. The lap belt must always pass
across your lap as low down as possible, i.e.
over your hip joints —not across your abdo-
men. If necessary, push the seat belt
slightly downwards and adjust it by pulling
it in the direction the seat belt retracts.
R Do not route the seat belt strap over sharp
or fragile objects. Please make sure that
such objects are not on or in your clothing,
e.g. spectacles, pens or keys etc. The seat
belt strap could become damaged and tear during an accident and you or other vehicle
occupants could be injured.
R Only one person should use each seat belt
at any one time. Children must never travel
sitting on the lap of another occupant. The
child will not be secured in the event of an
accident, heavy braking or sudden change
of direction .This may result in the child or
other occupants being seriously or fatally
injured.
R Persons under 1.50 mtall cannot wear the
seat belts correctly. For this reason secure
persons less than 1.50 m tall in specially
designed, suitable restraint systems.
R Children unde r1.50 mtall and younger
than twelve years of age canno twear the
seat belts correctly. For this reason secure
them in special suitable child restraint sys-
tems installed on a suitable seat. Additional
information can be found in the Operating
Instructions in the chapter "Safety", "Chil-
dren in the Vehicle". Observe the installa-
tion instructions of the child restraint sys-
tem manufacturer.
R Do not secure an object with a seat belt if
the seat belt is also being used by one of
the vehicle's occupants. G
WARNING
The seat belt does not offer the intended level
of protection unless the backrest is almost
vertical. Under certain circumstances, this
could cause severe or even fatal injuries in the
event of an accident.
Before starting a journey, make sure that the
seat is properly adjusted and that the back-
rest is almost vertical. G
WARNING
Ad irty or damaged seat belt or one that has
been modified or subjected to a load in an
accident no longer offers the intended level of
protection. Under certain circumstances, this
could cause severe or even fatal injuries in the
event of an accident. 44
Occupant safetySafety

For this reason, check regularly that the seat
belts are not damaged or dirty.
Always have damaged sea
tbelts or seat belts
that have been subjected to a load in an acci-
dent replaced at a qualified specialist work-
shop.
For safety reasons, Mercedes-Benz recom-
mends that you only use seat belts which have
been approved by Mercedes-Benz for your
vehicle.
Seat belts are the most effective means of
restraining the movement of vehicle occu-
pants in the event of an accident. This
reduces the risk of vehicle occupants coming
into contact with parts of the vehicle interior.
Fastening seat belts X
Adjust the seat and move the backrest to
an almost vertical position (Y page 86).
X Pull the seat belt smoothly through belt
sash guide :.
X Without twisting it, guide the shoulder sec-
tion of the seat belt across the middle of
your shoulder and the lap section across
your hips.
X Engage belt tongue ;in buckle =.
Seat belt adjustment:ifn ecessary, the driv-
er's and front-passenger seat belts auto- matically adjust to the upper body
(Y
page 45).
X If necessary, adjust the seat belt to the
appropriate height (Y page 45).
X If necessary, pull upwards on the shoulder
section of the seat belt to tighten the belt
across your body.
For more information about releasing the seat
belt with release button ?, see "Releasing
seat belts" (Y page 46).
Seat belt adjustment The seat-belt adjustment function adjusts the
driver's and front-passenger seat belt to the
upper body of the occupants.
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
2in 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 204).
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
protection)" section (Y page 43).
Belt height adjustment You can adjust the seat belt height on the
driver's seat and the front-passenger seat.
Adjust the height so that the upper part of the
seat belt is routed across the centre of your
shoulder. Occupant safety
45Safety Z

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 Release belt sash guide release :and
make sure tha tthe belt sash guide has
engaged.
Releasing 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 ?(Ypage 45) and
guide belt tongue ;back towards belt
sash guide :.
Belt warning for 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 con-
tinuously or flash. In addition, there may be a
warning tone.
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
the driver and the front passenger have fas-
tened their seat belts.
i For more information on the 7seat
belt warning lamp, see "Warning and indi-
cator lamps in the instrumentc luster, seat
belt" (Y page 231).
Rear seat belt status indicator The rear-compartmen
tseat belt status indi-
cator tells you if the rear passengers have
their seat belts fastened.
The rear-compartment seat belt status indi-
cator indicates the rear seat on which the belt
is fastened. The üsymbol in the display
indicates a fastened seat belt. If a seat belt is
not fastened or if a seat is not occupied, the
ý symbol is displayed.
The rear-compartment seat belt status indi-
cator appears in the multifunction display for
around 30 seconds if:
R you drive off and reach a speed of approx-
imately 10 km/h.
R the rear passengers fasten or unfasten
their seat belts while the vehicle is in
motion.
R someone gets in or out of the vehicle and
the vehicle drives off again. Example: the occupant on the left rear seat is
secured46
Occupant safetySafety

You can also cancel the rear seat belt status
indicator immediately:
X
Press the aor% button on the steer-
ing wheel.
i The status indicator for the rear-compart-
men tseat belts is only available for certain
countries.
Belt tensioners, belt force limiters G
WARNING
If the seat belt tensioners have been trig-
gered, they provide no additional protection
in the event of another accident. Therefore,
have belt tensioners which have been trig-
gered replaced at a qualified specialist work-
shop.
Comply with safety regulations when dispos-
ing of belt tensioners. Any Mercedes-Benz
Service Centre can provide details of these
regulations.
! If the front-passenger seat is not occu-
pied, do not engage the seat belt tongue in
the buckle on the front-passenger seat.
Otherwise, the belt tensioner could be trig-
gered in the event of an accident.
The fron tseat belts are equipped with belt
tensioners and belt force limiters. The outer
seat belts in the rear are equipped with seat
belt tensioners.
The belt tensioners tighten the seat belts in
an accident, pulling them close against the
body.
Belt tensioners do not correct incorrect seat
positions or incorrectly fastened seat belts.
Belt tensioners do not pull vehicle occupants
back towards the backrest.
When triggered, seat belt force limiters help
to reduce the peak forc eexerted by the seat
belt on the vehicle occupant.
The front belt force limiters are synchronised
with the front airbags, which take on a part of
the deceleratio nforce. Thus, the force exer- ted on the occupant is distributed over a
greater area.
The belt tensioners can only be activated
when:
R the ignition is switched on.
R the restraint systems are operational; see
"SRS warning lamp" (Y page 39).
R the belt tongue is engaged in the buckle on
each of the three-point seat belts in the
front.
The belt tensioners on the outside seats in the
rear compartment are triggered independ-
ently of the lock status of the seat belts.
The belt tensioners are triggered depending
on the type and severity of an accident:
R in the event of a head-on or rear-end colli-
sion if the vehicle decelerates or acceler-
ates rapidly in a longitudinal direction dur-
ing the initial stages of the impact
R in the event of a side impact if the vehicle
is subjected to high lateral acceleration/
deceleration
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. 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 Children in the vehicle
47Safety
Z