2012 MERCEDES-BENZ B-CLASS ECU

Checking the oil level using the oil
dipstick
Example
X
Pull oil dipstick : out of the dipstick guide
tube.
X Wipe off oil dipstick :.
X Slowly slide oil dipstick : into the guide
tube to the stop, and take it out again.
If the level is between MIN mark = and
MAX mark ;, the oil level is correct.
X If the oil level has dropped to MIN mark
= or below, add 1.1 US qt
(1.0 liter) of
engine oil.
Adding engine oil G
WARNING
If engine oil comes into contact with hot
components in the engine compartment, it
may ignite. There is a risk of fire and injury.
Make sure that engine oil is not spilled next
to the filler neck. Let the engine cool down
and thoroughly clean the engine oil off the
components before starting the engine. H
Environmental note
When adding oil, take care not to spill any. If
oil enters the soil or waterways, it is harmful
to the environment.
! Only use engine oils and oil filters that
have been approved for vehicles with a
service system. You

can obtain a list of the
engine oils and oil filters tested and
approved in accordance with the Mercedes-Benz Specifications for Service
Products at any Mercedes-Benz Service
center.
Damage to
the

engine or exhaust system is
caused by the following:
R using engine oils and oil filters that have
not been specifically approved for the
service system
R replacing engine oil and oil filters after
the interval for replacement specified by
the service system has been exceeded
R using engine oil additives.
! Do not add too much oil. adding too much
engine oil can result in damage to the
engine or to the catalytic converter. Have
excess engine oil siphoned off. Example: engine oil cap
X
Turn cap : counter-clockwise and remove
it.
X Add engine oil.
If the oil level is at or below the MIN mark
on the oil

dipstick, add 1.1 US qt (1.0 liter)
of engine oil.
X Replace cap : on the filler neck and turn
clockwise.
Ensure that the cap locks into place
securely.
X Check the oil level again with the oil
dipstick (Y page 268).
Further information on engine oil
(Y page 332). 268
Engine compartment
Maintenance and care
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These notes also apply to light alloy wheels
with a clear matte finish.
i
The vehicle should preferably be washed
by hand using a soft sponge, car shampoo
and plenty of water.
i Use only insect
remover and car shampoo
from the range of recommended and
approved Mercedes-Benz care products.
Cleaning the windows G
WARNING
You could become trapped by the windshield
wipers if they

start moving while cleaning the
windshield or wiper blades. There is a risk of
injury.
Always switch off the windshield wipers and
the ignition before cleaning the windshield or
wiper blades.
! Only fold the windshield wipers away from
the windshield when vertical. Otherwise,
you will damage the hood.
! Do not use dry cloths, abrasive products,
solvents or cleaning agents containing
solvents to clean the inside of the windows.
Do not touch the insides of the windows
with hard objects, e.g. an ice scraper or
ring. There is otherwise a risk of damaging
the windows.
! Clean the water drainage channels of the
windshield and the rear window at regular
intervals. Deposits such as leaves, petals
and pollen may under certain
circumstances prevent water from draining
away. This can lead to corrosion damage
and damage to electronic components.
X Clean the inside and outside of the
windows with a damp cloth and a cleaning
product that is recommended and
approved by Mercedes-Benz. Cleaning wiper blades G
WARNING
You could become trapped by the windshield
wipers if they

start moving while cleaning the
windshield or wiper blades. There is a risk of
injury.
Always switch off the windshield wipers and
the ignition before cleaning the windshield or
wiper blades.
! Only fold the windshield wipers away from
the windshield when vertical. Otherwise,
you will damage the hood.
! Do not pull the wiper blade. Otherwise,
the wiper blade could be damaged.
! Do not clean wiper blades too often and
do not rub them too hard. Otherwise, the
graphite coating could be damaged. This
could cause wiper noise.
X Fold the windshield wiper arms away from
the windshield.
X Carefully clean the wiper blades with a
damp cloth.
X Fold the windshield wiper arms back again
before switching on the ignition.
! Hold the wiper

arm securely when folding
back. The windshield could be damaged if
the wiper arm smacks against it suddenly.
Cleaning the exterior lighting !
Only use cleaning agents or cleaning
cloths which are suitable for plastic light
lenses. Unsuitable cleaning agents or
cleaning cloths could scratch or damage
the plastic light lenses.
X Clean the plastic lenses of the exterior
lighting using a wet sponge and a mild
cleaning agent, e.g. Mercedes-Benz car
shampoo or cleaning cloths.274
Care
Maintenance and care
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X
Open the tailgate.
X Lift the cargo compartment floor up
(Y page 246).
i Towing eye ; is located under tire
inflation compressor :.
Vehicles with a tire-change tool kit X
Open the tailgate.
X Lift the cargo compartment floor up
(Y page 246).
X Remove the tire-change tool kit.
The tire-change tool kit contains:
R Jack
R Lug wrench
R One pair of gloves
R Folding wheel chock Flat tire
Preparing the vehicle
Your vehicle may be equipped with:
R MOExtended tires (tires with run-flat
properties) ( Y page 281)
Vehicle preparation is not necessary on
vehicles with MOExtended tires.
R a TIREFIT kit (Y page 280)
Information on changing/mounting a wheel
(Y page 319).
X Stop the vehicle on solid, non-slippery and
level ground, as far away as possible from
traffic.
X Switch on the hazard warning lamps.
X Secure the vehicle against rolling away
(Y page 149).
X If possible, bring the front wheels into the
straight-ahead position.
X Switch off the engine.
X Remove the SmartKey from the ignition
lock. X
All occupants must get out of the vehicle.
Make sure that
they are not endangered as
they do so.
X Make sure that no one is near the danger
area while a wheel is being changed.
Anyone who is not directly assisting in the
wheel change should, for example, stand
behind the barrier.
X Get out of the vehicle. Pay attention to
traffic conditions when doing so.
X Close the driver's door.
i Vehicles equipped with

MOExtended tires
are not equipped with a TIREFIT kit at the
factory. It is therefore recommended that
you additionally equip your vehicle with a
TIREFIT kit if you mount tires that do not
feature run-flat properties, e.g. winter tires.
A TIREFIT kit can be obtained from a
qualified specialist workshop. MOExtended tires (tires with run-flat
properties)
General notes With MOExtended tires (tires with run flat
characteristics), you can continue to drive
your vehicle even if there is a total loss of
pressure in one or more tires. The affected
tire must
not

show any clearly visible damage.
You can recognize MOExtended tires by the
MOExtended marking which appears on the
sidewall of the tire. You will find this marking
next to the tire size designation, the load-
bearing capacity and the speed index
(Y page 313).
MOExtended tires may only be used in
conjunction with an active tire pressure loss
warning system.
If the pressure loss warning message
appears in the multifunction display:
R Observe the instructions in the display
messages ( Y page 219).
R Check the tire for damage.
R If driving on, observe the following notes. Flat tire
281
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necessary for you to disconnect the battery
yourself, make sure that:
R
you switch off
the engine and remove the
SmartKey. Check that all the indicator
lamps in the instrument cluster are off.
Otherwise, electronic components, such
as the alternator, may be damaged.
R you first remove the negative terminal
clamp and then the positive terminal
clamp. Never swap the terminal clamps.
Otherwise, the vehicle's electronic
system may be damaged.
R on vehicles with automatic transmission,
the transmission is locked in position P
after disconnecting the battery. The
vehicle is secured against rolling away.
You can then no longer move the vehicle.
The battery and the cover of the positive
terminal clamp must be installed securely
during operation.
Comply with safety precautions and take
protective measures when handling
batteries. WARNING
Fire, open flames and smoking are
prohibited when handling the
battery. Avoid creating sparks.
Battery acid is caustic. Avoid
contact with the skin, eyes or
clothing.
Wear suitable protective clothing,
in particular gloves, an apron and
a face mask.
Immediately rinse acid splashes
off with clean water. Consult a
doctor if necessary.
Wear eye protection. Keep children away.
Observe this Operator's Manual.
For safety reasons, Mercedes-Benz
recommends that you only use batteries
which have been tested and approved for
your vehicle by Mercedes-Benz. These
batteries provide increased impact
protection to prevent

vehicle occupants from
suffering acid burns should the battery be
damaged in the event of an accident.
In order for the battery to achieve the
maximum possible service life, it must always
be sufficiently charged.
Like other batteries, the vehicle battery may
discharge over time if you do not use the
vehicle. In this case, have the battery
disconnected at a qualified specialist
workshop. You can also charge the battery
with a charger recommended by Mercedes-
Benz. Contact a qualified specialist workshop
for further information.
Have the battery charge level checked more
frequently if you use the vehicle mainly for
short trips or if you leave it standing idle for
a lengthy period. Consult a qualified specialist
workshop if you wish to leave your vehicle
parked for a long period of time.
Only replace a battery with a battery that has
been recommended by Mercedes-Benz.
i Remove the SmartKey if you park the
vehicle and do not require any electrical
consumers. The vehicle will then use very
little energy, thus conserving battery
power. Battery (vehicle)
287
Breakdown assistance Z
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shorter. The starting characteristics can be impaired, particularly at low temperatures. Have
the thawed-out battery checked at a qualified specialist workshop.
Do not
start
the vehicle using a rapid charging device. If your vehicle's battery is discharged,
the engine can be jump-started from another vehicle or from a second battery using jumper
cables. Observe the following points:
R The battery is not accessible in all vehicles. If the other vehicle's battery is not accessible,
jump-start the vehicle using a second battery or a jump-starting device.
R You may only jump-start the vehicle when the engine and exhaust system are cold.
R Do not start the engine if the battery is frozen. Let the battery thaw first.
R Jump-starting may only be performed from batteries with a nominal voltage of 12 V.
R Only use jumper cables which have a sufficient cross-section and insulated terminal clamps.
R If the battery is fully discharged, leave the battery that is being used to jump-start connected
for a few minutes before attempting to start. This charges the battery slightly.
R Make sure that the two vehicles do not touch.
Make sure that:
R the jumper cables are not damaged.
R bare parts of the terminal clamp do not come into contact with other metal parts while the
jumper cables are connected to the battery.
R the jumper cables cannot come into contact with parts which can move when the engine
is running, such as the V-belt pulley or the fan.
X Secure the vehicle by applying the electric parking brake.
X Shift the transmission to position P.
X Turn the SmartKey to position 0 in the ignition lock and remove it.
X Switch off all electrical consumers (e.g. radio, blower, etc.).
X Open the hood (Y page 266).290
Jump-starting
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!
Only secure the
tow rope or tow bar at the
towing eyes. Otherwise, the vehicle could
be damaged.
! Do not use the towing eyes for recovery
purposes as this could damage the vehicle.
If in doubt, recover the vehicle with a crane.
! When towing, pull away slowly and
smoothly. If the tractive power is too high,
the vehicles could be damaged.
! The vehicle can be towed a maximum of
30 miles (50km). The towing speed of
30 mph (50km/h) must not be exceeded.
If the vehicle has to be towed more than
30 miles (50km), the front axle must be
raised or the entire vehicle raised and
transported.
! Do not tow with sling-type equipment.
This could damage the vehicle.
! Vehicles with automatic transmission
must not be started by tow-starting. This
could otherwise damage the transmission.
It is better to have the vehicle transported
than to have it towed.
When towing a vehicle, the transmission must
be in position N.
The battery must be connected and charged.
Otherwise, you:
R cannot turn the SmartKey to position 2 in
the ignition lock
R cannot shift the transmission to position
N.
i Deactivate the automatic locking feature
(Y page 198). You could otherwise be
locked out when pushing or towing the
vehicle. Installing/removing the towing eye
Installing the towing eye X
Remove the towing eye from the stowage
space.
The towing eye is beneath the cargo
compartment floor with

the vehicle tool kit
(Y page 280).
Vehicles with the TIREFIT kit: the towing
eye is beneath the tire inflation
compressor.
X Press the mark on cover : inwards in the
direction of the arrow.
X Take cover : off the opening.
X Screw in and tighten the towing eye
clockwise to the stop.
Removing the towing eye X
Unscrew and remove the towing eye.
X Attach cover : to the bumper and press
until it engages.
X Place the towing eye in the stowage well
beneath the cargo compartment floor
(Y page 280) in the cargo compartment.
X Vehicles with the TIREFIT kit: put back the
tire inflation compressor.292
Towing and tow-starting
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Towing the vehicle with the front axle
raised
! The ignition must be switched off if the
vehicle is being towed with the front axle
raised. Otherwise, ESP®

may intervene and
damage the brake system.
X Turn the SmartKey to position 2 in the
ignition lock.
X When the vehicle is stationary, depress the
brake pedal and keep it depressed.
X Shift the automatic transmission to
position P.
X Release the brake pedal.
X Release the electric parking brake.
X Deactivate automatic locking
(Y page 198).
X Switch on the hazard warning lamps
(Y page 101).
X Turn the SmartKey to position 0 in the
ignition lock and

leave the SmartKey in the
ignition lock.
When towing your vehicle with the front axle
raised, it is important that you observe the
safety instructions ( Y page 291).Towing a vehicle with both axles on
the ground
G
WARNING
The power assistance for the steering and the
brake force booster do not work when the
engine is not running. You will then need
much more effort to brake and steer the
vehicle. Adapt your style of driving
accordingly.
i In order to signal a change of direction
when towing with

the hazard warning lamps
switched on, use the combination switch as
usual. In this case, only the turn signals for
the desired direction flash. When you reset
the combination switch, the hazard
warning lamps start flashing again. The automatic transmission automatically
shifts
to position P

when you open the driver's
or front-passenger door or when you remove
the SmartKey from the ignition lock. In order
to ensure that the automatic transmission
stays in position N when towing the vehicle,
you must observe the following points:
X Make sure that the vehicle is stationary.
X Turn the SmartKey to position 2 in the
ignition lock.
X Depress and hold the brake pedal.
X Shift the automatic transmission to
position N.
X Leave the SmartKey in position 2 in the
ignition lock.
X Release the brake pedal.
X Release the electric parking brake.
X Switch on the hazard warning lamps
(Y page 101).
It is important that you observe the safety
instructions when towing away your vehicle
(Y page 291). Transporting the vehicle
! Only lash the

vehicle down by the wheels
or wheel rims, not by parts of the vehicle
such as axle or steering components.
Otherwise, the vehicle could be damaged.
X Turn the SmartKey to position 2 in the
ignition lock.
X Shift the transmission to position N.
As soon as the vehicle is loaded:
X Prevent the vehicle from rolling away by
applying the electric parking brake.
X Shift the transmission to position P.
X Turn the SmartKey to position 0 in the
ignition lock and remove it.
X Secure the vehicle.
The towing eye can be used to pull the vehicle
onto a trailer or transporter for transporting
purposes. Towing and tow-starting
293
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Tow-starting (emergency engine
starting)
! Vehicles with automatic transmission
must not be tow-started. You could
otherwise damage the automatic
transmission.
When tow-starting, it is important that you
observe the safety
instructions (Y page 291).Fuses
Important safety notes
G
WARNING
If you manipulate or bridge a faulty fuse or if
you replace it with a fuse with a higher
amperage, the electric cables could be
overloaded. This could result in a fire. There
is a risk of an accident and injury.
Always replace faulty

fuses with the specified
new fuses having the correct amperage.
! Only use fuses that have been approved
for Mercedes-Benz vehicles and which
have the correct fuse rating for the system
concerned. Only use fuses marked with an
"S". Otherwise, components or systems
could be damaged.
The fuses in your vehicle serve to close down
faulty circuits. If a fuse blows, all the
components on the circuit and their functions
stop operating.
Blown fuses must be replaced with fuses of
the same rating, which you can recognize by
the color and value. The fuse ratings are listed
in the fuse allocation chart.
If a newly inserted fuse also blows, have the
cause traced and rectified at a qualified
specialist workshop, e.g. an authorized
Mercedes-Benz Center. Before changing a fuse
X Secure the vehicle against rolling away
(Y page 149).
X Switch off all electrical consumers.
X Turn the SmartKey to position 0 in the
ignition lock and remove it (Y page 135).
All indicator lamps

in the instrument cluster
must be off.
The fuses are located in various fuse boxes:
R Fuse box in

the engine compartment on the
left-hand side of the vehicle, when viewed
in the direction of travel
R Fuse box in the front-passenger footwell
The fuse allocation chart is on the fuse box in
the front-passenger footwell ( Y page 295). Fuse box in the engine compartment
G
WARNING
When the hood is open and the windshield
wipers are set in motion, you can be injured
by the wiper linkage. There is a risk of injury.
Always switch off the windshield wipers and
the ignition before opening the hood.
! Make sure that

no moisture can enter the
fuse box when the cover is open.
! When closing the cover, make sure that it
is lying correctly on the fuse box. Moisture
seeping in or dirt could otherwise impair
the operation of the fuses. 294
Fuses
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