2012 MERCEDES-BENZ B-CLASS ECU

Further information on secure stowage of
loads can be found under "Loading
guidelines".
If an
infant
or child is traveling in the vehicle:
R Secure the child with a child or infant seat
restraint system appropriate to the age and
weight of the child.
R Make sure that the infant or child is
properly secured at all times while the
vehicle is in motion.
Mercedes-Benz recommends that you always
properly secure all infants and children with
a child or infant seat restraint system for the
trip.
The use of seat belts and infant and child
restraint systems is required by law in:
R all 50 states
R the U.S. territories
R the District of Columbia
R all Canadian provinces
Infants and children must always be seated in
an appropriate infant or child restraint system
recommended for the size and weight of the
child. The infant or child restraint system
must be properly secured in accordance with
the manufacturer's instructions.
All infant or child restraint systems must meet
the following standards:
R U.S. Federal Motor Vehicle Safety
Standards 213 and 225
R Canadian Motor Vehicle Safety Standards
213 and 210.2
Confirmation that the child restraint system
corresponds to the standards can be found
on an instruction label on the child restraint
system. This confirmation can also be found
in the installation instructions that are
included with the child restraint system.
Always read and follow the manufacturer's
instructions when using an infant or child
restraint system or booster seat.
Observe the warning labels in the vehicle
interior or on the infant or child restraint. Child restraint system on the front-
passenger seat G
WARNING
If the front-passenger air bag is not disabled:
R a child secured in a child restraint system
on the front-passenger seat could be
seriously or even

fatally injured by the front-
passenger air bag deploying. This is
especially a risk if the child is in the
immediate vicinity of the front-passenger
air bag when it deploys.
R never secure a child on the front-passenger
seat in a rearward-facing child restraint
system. Only secure a rearward-facing
child restraint system on a suitable rear
seat.
R always move the front-passenger seat to
the rearmost position if you secure a child
in a forward-facing child restraint system
on the front-passenger seat.
The front-passenger air bag is not disabled:
R on vehicles without an air bag deactivation
system on the front-passenger seat.
R on vehicles with an air bag deactivation
system on the front-passenger seat, unless
a child restraint system with transponders
for an air bag deactivation system is
installed on the front-passenger seat
R on vehicles with an air bag deactivation
system on the front-passenger seat, if the
PASSENGER AIR BAG OFF indicator lamp
4 is not lit.
To make you aware of this danger, a
corresponding warning sticker has been
affixed on the dashboard and on both sides of
the sun visor on the front-passenger side.
Information about recommended child
restraint systems is available at any
authorized Mercedes-Benz Center. 52
Children in the vehicle
Safety
ProCarManuals.com

X
Install the LATCH-type (ISOFIX) child
restraint system. Comply with the
manufacturer's instructions when
installing the LATCH-type (ISOFIX) child
restraint system.
LATCH-type (ISOFIX) is a standardized
securing system for specially designed child
restraint systems on
the rear seats. Securing
rings : for two LATCH-type (ISOFIX) child
restraint systems are installed on the left and
right of the rear seats.
Secure child restraint systems without a
LATCH-type (ISOFIX) child seat securing
system using the seat belts in the vehicle.
When installing child restraint systems, you
must observe the manufacturer's installation
instructions.
Top Tether Important safety notes
G
WARNING
If the red display is visible when the rear seat
backrest is upright, it means the rear seat
backrest is not engaged correctly.
Always engage the rear seat backrests in an
upright position if

there are passengers in the
rear compartment. Engage the rear seat
backrests in an upright position after you have
installed the Top Tether belt or if the extended
cargo compartment is not being used. Push
and pull the rear seat backrests to check
whether they are engaged correctly. The rear
seat backrest may fold down if it is not
engaged correctly. The child restraint system is then no longer supported correctly or held
in position and can no longer perform its
intended function. This can cause serious or
even fatal injuries.
Top Tether provides an additional connection
between a child restraint system, secured
with a
LATCH-type

(ISOFIX) child seat mount,
and the rear seat. This helps reduce the risk
of injury even further.
The Top Tether anchorage points are installed
on the rear side of the rear seat backrests.
X Move head restraint : upwards.
X Release rear seat backrest = and fold it
forwards ( Y page 240).
X Route Top Tether belt B under head
restraint : between the

two head restraint
bars.
X Hook Top Tether hook A of
Top
Tether belt
B into Top Tether anchorage ?. Children in the vehicle
55
Safety Z
ProCarManuals.com

Problems with the air bag deactivation system
Problem Possible causes/consequences and
M SolutionsThe 45
indicator lamp on the
center console is lit. A special Mercedes-Benz child restraint system with a
transponder for
air
bag deactivation system has been installed to
the front-passenger seat. The front-passenger front air bag has
therefore been disabled as desired. G
WARNING
There is no child restraint system installed on the front-passenger
seat. The air bag deactivation system is malfunctioning.
It is also

possible that the 6 SRS warning lamp lights up and/
or the 45 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,
for example:
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. Child-proof locks
Important safety notes G
WARNING
Activate the child-proof locks for the rear
doors and the override switch for the rear
windows when children are travelling in the
vehicle. Otherwise, the children could open
doors or side windows while the vehicle is in
motion and injure themselves or others. G
WARNING
When leaving the vehicle, always remove the
SmartKey from the ignition lock. Always take
the SmartKey with you and lock the vehicle.
Do not leave children unattended in the
vehicle, even if they are secured in a child
restraint system, or with access to an
unlocked vehicle. A child's unsupervised
access to a

vehicle could result in an accident
and/or serious personal injury. The children
could:
R injure themselves on parts of the vehicle
R be seriously or fatally injured through
excessive exposure to extreme heat or cold
R injure themselves or cause an accident with
vehicle equipment that can be operated
even if the SmartKey is removed from the
ignition lock or removed from the vehicle, Children in the vehicle
57
Safety
ZProCarManuals.com

such as seat adjustment, steering wheel
adjustment, or the memory function
If children open
a door, they could injure other
persons or get out of the vehicle and injure
themselves or be injured by following traffic.
Do not expose the child restraint system to
direct sunlight. The child restraint system's
metal parts, for example, could become very
hot, and the child could be burned on these
parts.
Child-proof locks for the rear doors G
WARNING
Children could open a rear door from inside
the vehicle. This could result in serious
injuries or an accident. Therefore, when
children ride in

the rear always secure the rear
doors with the child-proof locks. You can secure each door individually with
the child-proof
locks

on the rear doors. A door
secured with a child-proof lock cannot be
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
windows G
WARNING
When children ride on the vehicle's rear seats,
activate the override switch. Otherwise, the
children could be injured, e.g. by trapping
themselves in the rear side window. 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
Overview of driving safety systems
In this section,
you will find information about
the following driving safety systems:
R ABS ( Anti-lock Braking System)
(Y page 64)
R BAS ( Brake Assist System) ( Y page 59)
R COLLISION PREVENTION ASSIST (adaptive
Brake Assist and distance warning signal)
(Y page 60)
R Adaptive brake lights ( Y page 62)
R ESP ®
(Electronic Stability Program)
(Y page 62)
R EBD ( Electronic Brake force Distribution)
(Y page 64) 58
Driving safety systems
Safety
ProCarManuals.com

X
To open a front door: pull door
handle ;.
X To unlock a rear door: pull up locking
knob :.
The door is unlocked and can be opened.
X To open a rear door: pull door handle ;.
You can open a door from inside the vehicle
even if it has been locked. You can open the
rear doors from
inside the vehicle unless they
are secured by the child-proof lock
(Y page 58).
If the vehicle has previously been locked with
the SmartKey, opening a door from the inside
will trigger the anti-theft alarm system.
Switch off the alarm (Y page 65). Centrally locking and unlocking the
vehicle from the inside
You can centrally lock or unlock the vehicle
from the inside.

This can be useful if you wish
to lock the vehicle before pulling away, for
example. X
To unlock: press button :.
X To lock: press button ;.
The vehicle locks when all the doors and
the tailgate are closed.
Meanwhile, the fuel filler flap will not be
locked or unlocked.
You cannot unlock the vehicle centrally from
the inside if

the vehicle has been locked with
the SmartKey. You can open a door from inside the vehicle
even if it has been locked. You can open the
rear doors
from

inside the vehicle unless they
are secured by the child-proof lock
(Y page 58).
If the vehicle has previously been locked with
the SmartKey, opening a door from the inside
will trigger the anti-theft alarm system.
Switch off the alarm (Y page 65).
If the vehicle has been locked using the
locking button for the central locking, or has
been locked automatically, and a door is
opened from the inside:
R the vehicle will be fully unlocked if it had
previously been fully unlocked
R only the door which has been opened form
the inside is unlocked if only the driver's
door had been previously unlocked Automatic locking feature
X
To deactivate: press and hold button :
for about five

seconds until a tone sounds.
X To activate: press and hold button ; for
about five seconds until a tone sounds.
i If you press one of the two buttons and
do not
hear

a tone, the relevant setting has
already been selected.
The vehicle is locked automatically when the
ignition is switched on and the wheels are
turning. 74
Doors
Opening and closing
ProCarManuals.com

Seats
Important safety notes
G
WARNING
Children could become trapped if they adjust
the seats, particularly when unattended.
There is a risk of injury.
When leaving the vehicle, always take the
SmartKey with you
and lock the vehicle. Never
leave children unsupervised in the vehicle. G
WARNING
You could lose control of your vehicle if you
do the following while driving:
R adjust the driver's seat, head restraint,
steering wheel or mirrors
R fasten the seat belt
There is a risk of an accident.
Adjust the driver's seat, head restraint,
steering wheel and mirror and fasten your
seat belt before starting the engine. G
WARNING
If you adjust the seat height carelessly, you or
other vehicle occupants

could be trapped and
thereby injured. Children in particular could
accidentally press the electrical seat
adjustment buttons and become trapped.
There is a risk of injury.
While moving the seats, make sure that your
hands or other body parts do not get under
the lever assembly of the seat adjustment
system. G
WARNING
When you adjust a seat, you or other vehicle
occupants could become

trapped, e.g. on the
seat guide rail. There is a risk of injury.
Make sure when adjusting a seat that no one
has any body parts in the sweep of the seat. G
WARNING
The seat belt does not offer the intended level
of protection if the backrest is not in the
upright position. When

braking or in the event of an accident, you could slide underneath the
seat belt and sustain abdomen or neck
injuries, for
example.

This poses an increased
risk of injury or even fatal injury.
Adjust the seat properly before beginning
your journey. Always make sure that the seat
is in the upright position. G
WARNING
If head restraints are not installed and
adjusted correctly, they cannot provide
protection as intended.

There is an increased
risk of injury in the head and neck area, e.g.
in the event of an accident or when braking.
Always drive with the head restraints
installed. Before driving off, make sure for
every vehicle occupant that the center of the
head restraint supports the back of the head
at about eye level. G
WARNING
According to accident statistics, children are
safer when properly restrained on the rear
seats than on

the front-passenger seat. Thus,
we strongly recommend that children be
placed in the rear seat whenever possible.
Regardless of seating position, children 12
years old and under must be seated and
properly secured in an appropriately sized
child restraint system or booster seat
recommended for the size and weight of the
child. For additional information, see the
"Children in the vehicle" section.
A child's risk of serious or fatal injuries is
significantly increased if the child restraints
are not properly secured in the vehicle and/
or the child is not properly secured in the child
restraint.
! To avoid damage to the seats and the seat
heating, observe the following information:
R keep liquids from spilling on the seats. If
liquid is spilled on the seats, dry them as
soon as possible.
R if the seat covers are damp or wet, do not
switch on the seat heating. The seat Seats
87
Seats, steering wheel and mirrors Z
ProCarManuals.com

Useful information
i This Operator's Manual describes all
models and all standard and optional
equipment of your vehicle available at the
time of publication of the Operator's
Manual. Country-specific differences are
possible. Please note
that your vehicle may
not be equipped with all features
described. This also applies to safety-
related systems and functions.
i Read the information on qualified
specialist workshops: ( Y page 24).Notes on breaking-in a new vehicle
Important safety notes
New and replaced brake pads and discs only
reach their optimum braking effect after
several hundred kilometers of driving.
Compensate for this

by applying greater force
to the brake pedal. The first 1,000miles (1,500 km)
The more you

look after the engine when it is
new, the more satisfied you will be with its
performance in the future.
R You should therefore drive at varying
vehicle and engine speeds for the first
1,000 miles (1,500 km).
R Avoid heavy loads, e.g. driving at full
throttle, during this period.
R Change gear in good time, before the
tachometer needle is Ô of the way to the
red area of the tachometer.
R Do not manually shift to a lower gear to
brake the vehicle.
R If possible, do not depress the accelerator
pedal past the point of resistance
(kickdown).
R Ideally, for the first 1,000 miles (1,500 km),
drive in program E. After 1,000 miles (1,500km), you can
increase the
engine

speed gradually and bring
the vehicle up to full speed.
i You should also observe these notes on
breaking-in if the engine or parts of the
drive train on your vehicle have been
replaced.
i Always observe the respective speed
limits. Driving
Important safety notes
G
WARNING
Objects in the driver's footwell can restrict the
pedal travel or obstruct a depressed pedal.
The operating and road safety of the vehicle
is jeopardized. There is a risk of an accident.
Make sure that all objects in the vehicle are
stowed correctly, and that they cannot enter
the driver's footwell. Install the floormats
securely and as specified in order to ensure
sufficient clearance for

the pedals. Do not use
loose floormats. G
WARNING
Unsuitable footwear can hinder correct usage
of the pedals, e.g.:
R shoes with thick soles
R shoes with high heels
R slippers
There is a risk of an accident.
Wear suitable footwear to ensure correct
usage of the pedals. G
WARNING
If you switch off the ignition while driving,
safety-relevant functions are only available
with limitations, or

not at all. This could affect,
for example, the power steering and the brake
boosting effect. You will require considerably
more effort to steer and brake. There is a risk
of an accident. 134
Driving
Driving and parking
ProCarManuals.com

Pulling away
Automatic transmission i
It is only
possible to shift the transmission
from position P to the desired position if
you depress the brake pedal. Only then can
the parking lock be deactivated. If you do
not depress the brake pedal, the DIRECT
SELECT lever can still be moved but the
parking lock remains engaged.
i If the transmission oil temperature is
below Ò4 ‡ (Ò20 † ), you can only shift from
position P when the engine is running.
X Depress the brake pedal and keep it
depressed.
X Shift the transmission to position D or R.
X Release the brake pedal.
X Carefully depress the accelerator pedal.
The electric parking brake (Y page 150) is
automatically released.
The red ! indicator lamp in the
instrument cluster goes out.
i The vehicle locks

centrally once you have
pulled away. The locking knobs in the doors
drop down.
You can open the doors from the inside at
any time.
You can also deactivate the automatic
locking feature (Y page 198).
i Upshifts take place at higher engine
speeds after a cold start. This helps the
catalytic converter to reach its operating
temperature more quickly.
Hill start assist G
WARNING
After a short time, hill start assist will no
longer brake your vehicle and it could roll
away. There is

a risk of an accident and injury.
Therefore, quickly move your foot from the
brake pedal to the accelerator pedal. Never
leave the vehicle when it is held by hill start
assist. Hill start assist helps you when pulling away
forwards or in reverse on an uphill gradient.
It holds the vehicle for a short time after you
have removed
your

foot from the brake pedal.
This gives you enough time to move your foot
from the brake pedal to the accelerator pedal
and to depress it before the vehicle begins to
roll.
X Remove your foot from the brake pedal.
The vehicle is

then held for about a second.
X Pull away.
Hill start assist will not function if:
R you are pulling away on a level road or on
a downhill gradient.
R the transmission is in position N.
R the electric parking brake is applied.
R ESP ®
is malfunctioning.
Further information on holding the vehicle
stationary on uphill gradients ( Y page 143). ECO start/stop function
Important safety notes G
WARNING
If the engine is switched off automatically and
you exit the vehicle, the engine is restarted
automatically. The vehicle

may begin moving.
There is a risk of accident and injury.
If you wish to exit the vehicle, always turn off
the ignition and secure the vehicle against
rolling away.
General notes If the
¤ symbol is shown in the
multifunction display, the ECO start/stop
function switches the engine off
automatically when the vehicle stops.
The engine starts automatically when the
driver wants to pull away again. The ECO
start/stop function thereby helps you to
reduce the fuel consumption and emissions
of your vehicle. 136
Driving
Driving and parking
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