open bonnet MERCEDES-BENZ A CLASS 2012 User Guide

Display messages Possible causes/consequences and
M SolutionsTrans. oil overhea‐
ted Drive on with
care AMG vehicles: the transmission oil has overheated.
Manual drive program
M and the temporarily active manual drive
program are no longer available. The engine power output is
reduced.
X Allow the vehicle to cool down. 4matic currently
unavailable 4MATIC (permanent all-wheel drive) has overheated. The vehicle
is only driven by the front wheels.
X
Drive on.
The airflow cools 4MATIC more quickly.
When
the display message goes out, 4MATIC is available again
and the vehicle is driven by all four wheels. 4matic inoperative 4MATIC is malfunctioning. The vehicle is only driven by the front
wheels.
X
Visit a qualified specialist workshop. A The tailgate is open.
G WARNING
When the engine is running, exhaust gases can enter the vehicle
interior if the tailgate is open.
There is a risk of poisoning.
X Close the tailgate. ? The bonnet is open.
A warning tone also sounds.
G WARNING
The open bonnet may then block your view when the vehicle is in
motion.
There is a risk of an accident.
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Apply the electric parking brake.
X Close the bonnet. Active bonnet mal‐
function See Own‐
er's Manual The active bonnet (pedestrian protection) is not active due to a
malfunction or because it has already been triggered.
X
Visit a qualified specialist workshop. C At least one door is open. A warning tone also sounds.
X
Close all doors.254
Display messages
On-board computer and displays

Problem Possible causes/consequences and
M Solutions?
The red coolant warn-
ing lamp comes on
while the engine is run-
ning.
The coolant level is too low.
If the coolant level is correct, the airflow to the engine radiator
may be blocked or the electric engine radiator fan may be mal-
functioning.
The coolant is too hot and the engine is no longer being cooled
sufficiently.
X
Observe the additional display messages in the multifunction
display.
X Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.
X Secure the vehicle against rolling away ( Y page 162).
X Leave the vehicle and keep a safe distance from the vehicle until
the engine has cooled down.
X Check the coolant level and top up the coolant (Y page 288).
Observe the warning notes as you do so.
X If you have to top up the coolant frequently, have the engine
cooling system checked.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by frozen slush.
X Do not start the engine again until the coolant temperature is
below
120 †. The engine may otherwise be damaged.
X Drive to the nearest qualified specialist workshop.
X Avoid heavy loads on the engine as you do so, e.g. driving in
mountainous terrain and stop-start traffic. ?
The red coolant warn-
ing lamp comes on
while the engine is run-
ning. A warning tone
also sounds.
The coolant temperature has exceeded 120

†. The airflow to the
engine radiator may be blocked or the coolant level may be too
low.
G WARNING
The engine is not being cooled sufficiently and may be damaged.
Never
drive with an overheated engine. Driving when your engine
is overheated can cause some fluids which may have leaked into
the engine compartment to catch fire.
Steam from an overheated engine can cause serious burns which
can occur just by opening the bonnet.
This poses a risk of injury.
X Observe the additional display messages in the multifunction
display.
X Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.
X Secure the vehicle against rolling away ( Y page 162).Warning and indicator lamps in the instrument cluster
265
On-board computer and displays Z

Useful information
i This Owner's Manual describes all mod-
els,
series and optional equipment for your
vehicle that were available at the time of
going to press. National variations are pos-
sible. Note that your vehicle may not be
equipped with all of the functions descri-
bed. This is also the case for systems and
functions relevant to safety.
i Read the information on qualified special-
ist workshops: (Y page 24). Engine compartment
Bonnet
Important safety notes G
WARNING
An unlocked bonnet may open while driving
and
block your view. There is a risk of an acci-
dent.
Never unlock the bonnet while driving. G
WARNING
When being opened and closed, the bonnet
may suddenly fall into the closed position.
There

is a risk of injury to persons in the range
of movement of the bonnet.
Open and close the bonnet only when nobody
is in the range of movement. G
WARNING
Certain components in the engine compart-
ment could be very hot, e.g. the engine, the
radiator and parts of the exhaust system.
There is a risk of injury when accessing the
engine compartment.
As far as possible, allow the engine to cool
down and only touch the following compo-
nents. G
WARNING
If you open the bonnet while the engine is
overheating or while there is a fire in the engine compartment, you could come into
contact with hot gases or other leaking
service products. There is a danger of injury.
Allow an overheating engine to cool down
before

opening the bonnet. If there is a fire in
the engine compartment, leave the bonnet
closed and notify the fire brigade. G
WARNING
There are parts in the engine compartment
that
move. Certain components may continue
to run even if the ignition is switched off or
may suddenly start again, e.g. the radiator
fan. There is a danger of injury.
If you need to access the engine compart-
ment:
R switch off the ignition
R never enter the danger area of moving com-
ponents, e.g. the rotation area of the fan
R keep items of clothing away from moving
parts G
WARNING
The ignition system and the fuel injection sys-
tem operate with a high voltage. If you touch
the live components, you could receive an
electric shock. There is a danger of injury.
Never touch components of the ignition sys-
tem or the fuel injection system when the
ignition is switched on.
Active bonnet (pedestrian protection) Operating principle
!
Once

triggered, an active bonnet must be
reset at a qualified specialist workshop,
e.g. a Mercedes-Benz Service Centre. The
active bonnet function will then be availa-
ble again. The additional pedestrian pro-
tection provided by the active bonnet will
then be restored.
The active bonnet is only available in certain
countries.
The active bonnet can reduce the risk of injury
to pedestrians in certain accident situations. 284
Engine compartment
Maintenance and care

Raising the active bonnet increases the clear-
ance
to hard components, such as the engine.
If the active bonnet has been triggered, it is
raised at the rear in the area around the hinge
by approximately 60 mm.
For the drive to the workshop, reset the trig-
gered active bonnet yourself. If the active
bonnet has been triggered, pedestrian pro-
tection may be limited.
Resetting G
WARNING
Certain components in the engine compart-
ment could be very hot, e.g. the engine, the
radiator and parts of the exhaust system.
There is a risk of injury when accessing the
engine compartment.
As far as possible, allow the engine to cool
down and only touch the following compo-
nents. X
With your hand flat, push down active bon-
net : in the area around the hinges on
both

sides (arrows) until you feel it engage.
If you can raise the active bonnet slightly in
the
area around the hinges, it is not engaged
correctly. Repeat the step.
If the bonnet can then still be raised, drive
directly to a qualified specialist workshop. Do
not drive faster than 100 km/h. Opening the bonnet G
WARNING
When the bonnet is open, and the windscreen
wipers are set in motion, you can be injured
by the wiper linkage. There is a risk of injury.
Always switch off the windscreen wipers and
the ignition before opening the bonnet.
! Make

sure that the windscreen wipers are
not folded away from the windscreen. Oth-
erwise, you could damage the windscreen
wipers or the bonnet. X
Make sure that the windscreen wipers are
switched off.
X Pull release lever : on the bonnet.
The bonnet is released. X
Reach into the gap between the bonnet and
the radiator trim and press bonnet catch
lever ; to the left.
X Raise the bonnet. Engine compartment
285
Maintenance and care Z

X
Pull support strut ? out of bracket A.
X Lift up support strut ? and insert it into
yellow retaining clip =.
Closing the bonnet X
Raise the bonnet slightly and, at the same
time, remove support strut ? from yellow
retaining clip =.
X Swing support strut ? down and press it
into bracket A until it engages.
X Lower the bonnet and let it fall from a
height of approximately
20 cm.
X Check that the bonnet has engaged prop-
erly.
If

the bonnet can be raised slightly, it is not
properly engaged. Do not press the bonnet
closed. Open the bonnet again and close it
with a little more force. Engine oil
General notes Depending on your driving style, the vehicle
consumes

up to 0.8 l of oil per 1,000 km. The
oil consumption may be higher than this when
the vehicle is new or if you frequently drive at
high engine speeds.
Depending on the engine, the oil dipstick may
be installed at a different location. When checking the oil level:
R
park the vehicle on a level surface.
R the engine should be switched off for
approximately five minutes if the engine is
at normal operating temperature.
R if the engine is not at normal operating
temperature, e.g. if the engine was only
started briefly: wait about

30 minutes
before carrying out the measurement. 286
Engine compartment
Maintenance and care

G
WARNING
A discharged battery can freeze at tempera-
tures below freezing point. When jump-start-
ing
the vehicle or charging the battery, gases
can escape from the battery. There is a risk of
an explosion.
Allow the frozen battery to thaw out before
charging it or jump-starting.
! Only use battery chargers with a maxi-
mum charging voltage of 14.8 V.
! Only charge the battery using the jump-
start connection point.
The jump-starting connection point is in the
engine compartment (Y page 308).
X Open the bonnet (Y page 285).
X Connect the battery charger to the positive
terminal

and earth point in the same order
as when connecting the donor battery in
the jump-starting procedure
(Y page 308).
If the indicator/warning lamps do not light up
at low temperatures, it is very likely that the
discharged battery has frozen. In this case
you may neither jump-start the vehicle nor
charge the battery. The service life of a bat-
tery

that has been thawed could be reduced.
The starting characteristics may be impaired,
especially at low temperatures. Have the
thawed battery checked at a qualified spe-
cialist workshop.
Only charge the installed battery with a bat-
tery charger which has been tested and
approved by Mercedes-Benz. A battery
charger unit specially adapted for Mercedes-
Benz vehicles and tested and approved by
Mercedes-Benz is available as an accessory.
It permits the charging of the battery in its
installed position. Contact a Mercedes-Benz
Service Centre for information and availabil-
ity. Read the battery charger's operating
instructions before charging the battery. Battery (vehicle)
307
Breakdown assistance Z

characteristics may be impaired, especially at low temperatures. Have the thawed battery
checked at a qualified specialist workshop.
Do
not use a rapid charging device to start the vehicle. If your vehicle's battery is discharged,
the engine can be jump-started from another vehicle or from a second battery using jump
leads. 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 Vehicles with a petrol engine: 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 jump leads that 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 empty battery a little.
R Make sure that the two vehicles do not touch.
Make sure that:
R the jump leads are not damaged.
R bare parts of the terminal clamp do not come into contact with other metal parts while the
jump leads are connected to the battery.
R the jump leads 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 Manual transmission: shift into neutral.
X Automatic transmission: shift the transmission to position P.
X Turn the key to position 0 in the ignition lock and remove it.
X Switch off all electrical consumers (e.g. radio, blower, etc.).
X Open the bonnet (Y page 285). Jump-starting
309
Breakdown assistance Z

The fuse allocation chart is on the fuse box in
the front-passenger footwell (
Y page 315).Fuse box in the engine compartment
G
WARNING
When the bonnet is open, and the windscreen
wipers are set in motion, you can be injured
by the wiper linkage. There is a risk of injury.
Always switch off the windscreen wipers and
the ignition before opening the bonnet.
! 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. X
Open the bonnet.
X Remove any existing moisture from the
fuse box using a dry cloth.
X To open: open clamps ;.
X Fold cover : up in the direction of the
arrow and remove it. X
To close: check whether the seal is lying
correctly in cover :.
X Insert cover : at the back into openings
= on the fuse box.
X Fold down cover :.
X Hook clamps ; into the fuse box and
close.
X Close the bonnet. Fuse box in the front-passenger foot-
well
X
To open: remove the floormat from the
front-passenger side.
X Fold out perforated floor covering :
in the
direction of the arrow. Electrical fuses
315
Breakdown assistance Z