2012 MERCEDES-BENZ A CLASS bonnet

Display messages Possible causes/consequences and
M SolutionsThe auxiliary heating cannot be switched on or has switched itself
off.
There is too little fuel in the fuel tank.
X
Refuel at the nearest filling station.
X Make another attempt to switch on the auxiliary heating using
the remote control. The auxiliary heating cannot be switched on or has switched itself
off.
The auxiliary heating is faulty.
X
Have the auxiliary heating checked at a qualified specialist
workshop. Adjusting the air vents
Important safety notes
G
WARNING
Very hot or very cold air can flow from the air
vents. This could result in burns or frostbite in
the immediate vicinity of the air vents. There
is a risk of injury.
Make sure that all vehicle occupants always
maintain a sufficient distance to the air out-
lets. If necessary, redirect the airflow to
another area of the vehicle interior.
In order to ensure the direct flow of fresh air
through the air vents into the vehicle interior,
please observe the following notes:
R keep the air inlet between the windscreen
and the bonnet free of blockages, such as
ice, snow or leaves.
R never cover the vents or ventilation grilles
in the vehicle interior.
i Move the adjusters for the air vents ver-
tically or horizontally, to set the direction of
the airflow.
i Optimal climate control function is ach-
ieved by opening the air vents fully and set-
ting the adjusters to the middle position. Setting the centre air vents
X
To open the centre air vent: turn the
adjuster in one of centre air vents : anti-
clockwise.
X To close the centre air vent: turn the
adjuster
in one of centre air vents : clock-
wise until it engages. Adjusting the air vents
139
Climate control Z

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 :
ECO start/stop display
If the ¤ symbol is shown in green in the
multifunction display, the ECO start/stop
function switches the engine off automati-
cally if the vehicle stops moving.
The

stop/start function is automatically acti-
vated each time you start the engine with the
ignition key.
If the ECO start/stop function has been man-
ually deactivated ( Y page 147) or a malfunc-
tion has caused the system to be deactivated,
the ¤ symbol is not displayed.
AMG vehicles: the ECO start/stop function
is only available in drive program C.
Automatic engine switch-off General notes
The ECO start/stop function is operational
and the
¤ symbol is displayed in green in
the multifunction display, if:
R the indicator lamp in the ECO button is lit
green
R the

outside temperature is within the range
that is suitable for the system R
the engine is at normal operating temper-
ature
R the

set temperature for the vehicle interior
has been reached
R the battery is sufficiently charged
R the system detects that the windscreen is
not misted up when the air-conditioning
system is switched on
R the bonnet is closed
R the driver's door is closed and the driver's
seat belt is fastened
If not all conditions for automatic engine
switch-off are fulfilled, the ¤ symbol is
shown in yellow.
i All of the vehicle's systems remain active
when the engine is switched off automati-
cally.
i The engine can be switched off automat-
ically a maximum of four times (initial stop,
then three subsequent stops) in succes-
sion. The ¤ symbol is shown in yellow
in the multifunction display after the engine
has been started automatically for the
fourth time. When the ¤ symbol is
shown in green in the multifunction display,
automatic engine switch-off is again possi-
ble.
Vehicles with manual transmission
The ECO start/stop function switches off the
engine automatically at low speeds. X
Brake the vehicle.
X Engage neutral N(Y page 151) (follow
gearshift instruction : to engage neutral
N, if necessary).
X Release the clutch pedal.
The engine is switched off automatically.146
Driving
Driving and parking

The electric parking brake secures the vehicle
automatically if the HOLD function is activa-
ted and:
R
the driver's door is open and the driver's
seat belt is unfastened
R the
engine is switched off, unless it is auto-
matically switched off by the ECO start/
stop function
R a system fault occurs
R the power supply is not sufficient
Vehicles with automatic transmission
If a fault occurs, then the transmission may
also be shifted into position P automatically.
Vehicles with manual transmission
The Brake immediately message can also
appear in the multifunction display.
X Immediately depress the brake pedal firmly
until

the warning message in the multifunc-
tion display goes out.
The HOLD function is deactivated.
A horn will sound at regular intervals if you
turn off the engine, take off your seat belt or
open the driver's door when the HOLD func-
tion is activated. The horn alerts you to the
fact that the HOLD function is still activated.
If you attempt to lock the vehicle, the tone
becomes louder. The vehicle cannot be
locked until you have deactivated the HOLD
function.
i Once you have switched off the engine,
you cannot restart it until you have deacti-
vated the HOLD function. RACE START
Important safety notes RACE START enables optimum acceleration
from a standing start. The precondition for
this is a suitable high-grip road surface.
Only

activate RACE START on dedicated race
circuits. i
RACE
START is only available in AMG vehi-
cles.
Activation conditions You can activate RACE START if:
R
the doors, the bonnet and the tailgate are
closed
R the

engine is running and the transmission,
traction control and engine are at operating
temperature
R SPORT handling mode is activated
(Y page 66)
R the steering wheel is in the straight-ahead
position.
R the vehicle is stationary and the brake
pedal is depressed (left foot)
R the transmission is in position D.
R drive program M is selected ( Y page 155).
Activating RACE START X
Depress the brake pedal with your left foot
and keep it depressed.
X Pull and hold both steering wheel gearshift
paddles.
X The RACE START Confirm: Paddle UP
Cancel: Paddle DOWN message appears
in the multifunction display.
X Release both steering wheel gearshift pad-
dles.
i If the activation conditions are no longer
fulfilled, RACE START is cancelled. The
RACE START not possible See Own‐
er's

Manual message appears in the mul-
tifunction display.
X To cancel:
pull the left steering wheel shift
paddle (Y page 156).
or
X To confirm: pull the right steering wheel
shift paddle

(Y page 156).
The RACE START available Depress
accelerator message appears in the mul-
tifunction display. Driving systems
181
Driving and parking Z

Display messages Possible causes/consequences and
M Solutions?
Coolant Stop vehi‐
cle Switch engine
off The coolant is too hot.
A warning tone also sounds.
G WARNING
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.
There is a risk of injury.
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 Wait until the engine has cooled down.
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 display message goes out
and the coolant temperature is below

120 †. The engine may
otherwise be damaged.
X Pay attention to the coolant temperature display.
X If the temperature increases again, visit a qualified specialist
workshop immediately.
Under normal operating conditions and with the specified coolant
level, the coolant temperature may rise to
120 †.# The battery is not being charged.
A warning tone also sounds.
Possible causes:
R
faulty alternator
R torn poly-V-belt
R a malfunction in the electronics
X Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.
X Open the bonnet.
X Check whether the poly-V-belt is torn.
If the poly-V-belt is torn:
! Do

not continue driving. The engine could otherwise overheat.
X Consult a qualified specialist workshop.
If the poly-V-belt is OK:
X Visit a qualified specialist workshop immediately.244
Display messages
On-board computer and displays

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