2012 MERCEDES-BENZ A CLASS warning light

Indicator and warning display
Blind
Spot Assist is not active at speeds below
approximately 30 km/h. Vehicles in the mon-
itoring range are then not indicated. :
Yellow indicator lamp/red warning lamp
If Blind Spot Assist is switched on, indicator
lamp : in the exterior mirrors lights up yel-
low up to a speed of

30 km/h. At speeds
above 30 km/h, the indicator lamp goes out
and Blind Spot Assist is operational.
If a vehicle is detected within the monitoring
range of Blind Spot Assist at speeds above
30 km/h, warning lamp : on the corre-
sponding side lights up in red. This warning
always occurs when a vehicle enters the blind
spot monitoring range from behind or from
the side. When you overtake a vehicle, the
warning only occurs if the difference in speed
is less than 12 km/h.
The yellow indicator lamp goes out if reverse
gear is engaged. Blind Spot Assist is then
deactivated.
The brightness of the indicator/warning
lamps is adjusted automatically according to
the ambient light.
Collision warning
If a vehicle is detected in the monitoring range
of Blind Spot Assist and you switch on the
corresponding turn signal, a double warning
tone sounds. Red warning lamp : flashes. If
the turn signal remains on, detected vehicles
are indicated by the flashing of red warning
lamp :. There are no further warning tones. Activating Blind Spot Assist
X
Make sure that the radar sensor system
(Y page 223) and Blind Spot Assist
(Y page

219) are activated in the on-board
computer.
X Turn the key to position 2 in the ignition
lock.
Warning lamps : in the exterior mirrors
light up red for approximately
1.5 seconds

and then turn yellow.
Towing a trailer
If
you attach a trailer, make sure that you have
correctly established the electrical connec-
tion. This can be accomplished by checking
the trailer lighting. Blind Spot Assist is then
deactivated. The indicator lamp lights up yel-
low in the exterior mirrors and the Blind
Spot Assist currently unavailable
See Owner's Manual message appears in
the multifunction display.
i You can deactivate the indicator lamps in
the exterior mirrors.
To do so, switch off Blind Spot Assist if:
R the key is in position 2 in the ignition
lock.
R the engine is not running.
R the electrical connection to the trailer
has been established.
Lane Keeping Assist General notes
Lane Keeping Assist monitors the area in
front

of your vehicle by means of a camera at
the top of the windscreen. Lane Keeping
Assist detects lane markings on the road and
warns you before you leave your lane unin-
tentionally. Driving systems
199
Driving and parking Z

X
To open the cover: turn handle : anti-
clockwise and fold down cover ; and
remove it. X
Pull out release wheel =.
X Turn release wheel = anti-clockwise as far
as it will go.
The ball coupling disengages and folds out
behind the rear bumper. Indicator
lamp ? flashes. G
WARNING
If the ball coupling is not correctly engaged,
the trailer can detach. There is a risk of an
accident.
Always

engage the ball coupling as described.
X Pull the ball coupling in the direction of the
arrow

until it engages in a vertical position.
Indicator lamp ? goes out. The power
socket folds down automatically.
The multifunction display shows the
Check trailer hitch lock display mes-
sage until the ball coupling is engaged.
X Remove the protective covering from the
ball coupling and store it in a safe place.
X Make sure that the ball of the ball coupling
is clean and that it is either greased or dry
(grease free), depending on the instruc-
tions for the trailer. Coupling up a trailer
X Make sure that the transmission is in posi-
tion P.
X Apply the electric parking brake.
X Position the trailer level behind the vehicle.
X Couple up the trailer.
X Establish the electric connection between
the vehicle and the trailer.
X Check that the trailer lighting system is
working.
A trailer that is connected is recognised
only when the electrical connection is
established

correctly and when the lighting
system is working properly. The function of
other systems, such as ESP ®
or PARK-
TRONIC also depends on this. Uncoupling a trailer
G
WARNING
If you uncouple a trailer with an engaged over-
run
brake, you could trap your hand between204
Towing a trailer
Driving and parking

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). Important safety notes
G
WARNING
Operating the integrated information systems
and
communications equipment in the vehicle
while driving will distract you from traffic con-
ditions. You could then lose control of the
vehicle. There is a risk of an accident.
Only operate these devices if road traffic con-
ditions permit. If you are unsure about the
surrounding conditions, pull over to a safe
location and make entries only while the vehi-
cle is stationary. G
WARNING
If the instrument cluster has failed or mal-
functioned, you may not recognise function
restrictions relevant to safety. The operating
safety

of your vehicle may be impaired. There
is a risk of an accident.
Drive on carefully. Have the vehicle checked
at a qualified specialist workshop immedi-
ately.
You must observe the legal requirements for
the country in which you are currently driving
when operating the on-board computer.
The on-board computer only shows messages
or warnings from certain systems in the mul-
tifunction display. You should therefore make
sure your vehicle is operating safely at all times. Otherwise, a vehicle that is not oper-
ating safely may cause an accident.
For an overview, see the instrument panel
illustration (
Y page 30). Displays and operation
Instrument cluster lighting
The lighting in the instrument cluster, in the
displays and the controls in the vehicle inte-
rior

can be adjusted using the brightness con-
trol knob.
The brightness control knob is on the bottom
left of the instrument cluster ( Y page 30).
X Turn the brightness control knob clockwise
or anti-clockwise.
If the light switch is set to Ã, T or
L, the brightness is dependant upon
the brightness of the ambient light.
i The
light sensor in the instrument cluster
automatically controls the brightness of
the multifunction display.
In daylight, the displays in the instrument
cluster are not illuminated. Coolant temperature gauge
The coolant temperature gauge is in the
instrument cluster on the right-hand side.
The

reading may rise up to 120 † below nor-
mal driving conditions if the coolant has been
filled correctly.
At high outside temperatures and when driv-
ing uphill, the coolant temperature may rise
to the end of the scale. Rev counter
! Do not drive in the overrevving range.
Doing so will damage the engine.
The

red band in the rev counter indicates the
engine's overrevving range. 208
Displays and operation
On-board computer and displays

Speed Limit Assist
Displaying Speed Limit Assist
X
Press the = or ; button on the steer-
ing wheel to select the Assist. menu.
X Press the 9 or : button to select
Speed Limit Assist.
X Press the a button.
Under certain conditions, detected speed
limits are shown in the multifunction dis-
play

(Y page 196).
Activating/deactivating the Speed Limit
Assist message function
X Press the =
or ; button on the steer-
ing wheel to select the Assist. menu.
X Press the 9 or : button to select
Speed Limit Assist.
X Press the a button.
The multifunction display shows Speed
Limit Assist.
X Press the : button.
The current selection is displayed.
X To activate or deactivate: press a.
If
the Speed Limit Assist message function
is activated, a detected speed limit is auto-
matically displayed for five seconds. Other
items in the multifunction display are not
shown during this time.
When Speed Limit Assist is operational and
the message function is activated, the
assistance graphic shows the Ä sym-
bol.
Deactivating/activating ESP ®i
Observe
the "Important safety notes" sec-
tion in the description of ESP ( Y page 65).G
WARNING
If you deactivate ESP ®
, ESP ®
no longer sta-
bilises the vehicle. There is an increased risk
of skidding and an accident.
Only

deactivate ESP ®
in the situations descri-
bed in the following. It may be best to deactivate ESP
®
in the fol-
lowing situations:
R when using snow chains
R in deep snow
R on sand or gravel
Deactivating/activating ESP ®
on AMG vehi-
cles ( Y page 66).
For further information about ESP ®
, see
(Y page 65).
X Start the engine.
X Press the =
or ; button on the steer-
ing wheel to select the Assist. menu.
X Press the 9 or : button to select
ESP.
X Press the a button.
X To activate/deactivate: press the a
button again.
ESP ®
is deactivated if the å warning
lamp in the instrument cluster lights up
continuously when the engine is running.
If the ÷
warning lamp and the å warn-
ing lamp are lit continuously, ESP ®
is not
available due to a malfunction.
Observe the information on warning lamps
(Y page 260).
Observe the information on display messages
(Y page 230).
Activating/deactivating the distance
warning function X
Press the =
or ; button on the steer-
ing wheel to select the Assist. menu.
X Press the 9 or : button to select
Distance warning.
X Press the a button.
The current selection is displayed.
X To activate/deactivate: press the a
button again.
When the distance warning function is
deactivated, the æ symbol appears in
the multifunction display in the assistance
graphics display. 218
Menus and submenus
On-board computer and displays

X
Press the 9 or : button to select
Radar sensor (See Owner's Man.).
You will see the selected setting: Activa‐
ted or Deactivated.
X Press the a button to save the setting.
i In some countries you must deactivate
the radar sensor system. For further infor-
mation, see ( Y page 350).
If the radar sensor system is switched off,
Blind Spot Assist is deactivated
(Y page 197).
Heating Changing the departure time
X
Press the = or ; button on the steer-
ing wheel to select the Settings menu.
X Press the : or 9 button to select
theHeating submenu.
X Press a to confirm.
You will see the selected setting.
X Press a to confirm.
X Press the : or 9
button to select A,
B or Change C.
X Press a to confirm.
You can now change the departure time.
X Press the =
or ; button to select the
display to be changed: hours, minutes.
X Press the : or 9 button to set the
selected display.
X Press the a button to store the entry.
The yellow indicator lamp on the auxiliary
heating button lights up.
Selecting the departure time or deactivat-
ing a selected departure time
X Press the =
or ; button on the steer-
ing wheel to select the Settings menu.
X Press the :
or 9 button to select the
Heating submenu.
X Press a to confirm.
You will see the selected setting.
X Press a to confirm. X
Press : or 9 to select one of the
three departure times or Timer off (no
timer active).
X Press a to confirm.
If a departure time is selected, the yellow
indicator lamp lights up on the auxiliary
heating button.
Changing the departure time
Only vehicles with auxiliary heating
(Y page 134) have this function.
In the Heating submenu, you can select a
stored

departure time or change a departure
time.
The auxiliary heating timer function calcu-
lates the switch-on time according to the out-
side temperature so that the vehicle is pre-
heated by the departure time. When the
departure time is reached, the auxiliary heat-
ing continues to heat for a further five
minutes and then switches off. The auxiliary
heating adopts the THERMATIC or
THERMOTRONIC temperature setting.
You can switch off the auxiliary heating by
using the remote control or the auxiliary heat-
ing button on the centre console. G
DANGER
If the exhaust pipe is blocked or sufficient
ventilation is not possible, toxic exhaust
fumes can enter the vehicle, especially car-
bon monoxide. This is the case, e.g. in
enclosed spaces, or if the vehicle is stuck in
snow. There is a risk of fatal injuries.
You should switch off the auxiliary heating in
enclosed

spaces which do not have an extrac-
tion system, e.g. a garage. If the vehicle is
stuck in snow and you must leave the auxiliary
heating running, keep the exhaust pipe and
the area around the vehicle clear of snow. To
guarantee a sufficient supply of fresh air, open
a window on the side of the vehicle away from
the wind. G
WARNING
When the auxiliary heating is switched on,
parts of the vehicle can become very hot. 224
Menus and submenus
On-board computer and displays

Safety systems
Display messages Possible causes/consequences and
M Solutions!÷
currently unavail‐
able See Owner's
Manual ABS (Anti-lock Braking System), ESP
®
(Electronic Stability Pro-
gram), BAS (Brake Assist), PRE-SAFE ®
, the HOLD function, hill
start assist and ESP ®
trailer stabilisation are temporarily unavail-
able.
The adaptive brake lights and COLLISION PREVENTION ASSIST
may also have failed.
In addition, the ÷, å and ! warning lamps light up in
the instrument cluster.
ATTENTION ASSIST is deactivated.
Possible causes:
R self-diagnosis is not yet complete.
R the on-board voltage may be insufficient
G WARNING
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
The
steerability and braking characteristics may be severely affec-
ted. The braking distance may increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Carefully drive on a suitable stretch of road, making slight steer-
ing movements, at a speed above

20 km/h.
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed:
X Drive on carefully.
X Visit a qualified specialist workshop. !÷
inoperative See
Owner's Manual ABS, ESP
®
, BAS, PRE-SAFE ®
, the HOLD function, hill start assist
and
ESP®
trailer stabilisation are unavailable due to a malfunction.
The adaptive brake lights and COLLISION PREVENTION ASSIST
may also have failed.
In addition, the J, ÷, å and ! warning lamps light
up in the instrument cluster.
ATTENTION ASSIST is deactivated.
G WARNING230
Display messages
On-board computer and displays

Display messages Possible causes/consequences and
M SolutionsThe brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
The
steerability and braking characteristics may be severely affec-
ted. The braking distance may increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Drive on carefully.
X Visit a qualified specialist workshop immediately. ÷
currently unavail‐
able See Owner's
Manual ESP
®
, BAS, PRE-SAFE ®
, the HOLD function, hill start assist and
ESP ®
trailer stabilisation are temporarily unavailable.
The adaptive brake lights and COLLISION PREVENTION ASSIST
may also have failed.
In addition, the ÷ and å warning lamps light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
The self-diagnosis function, for example, may not be complete.
G WARNING
The brake system continues to function normally, but without the
functions listed above.
The

braking distance may thus increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Carefully drive on a suitable stretch of road, making slight steer-
ing movements, at a speed above

20 km/h.
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed:
X Drive on carefully.
X Visit a qualified specialist workshop. Display messages
231
On-board computer and displays Z

Display messages Possible causes/consequences and
M Solutions÷
inoperative See
Owner's Manual ESP
®
, BAS, PRE-SAFE ®
, the HOLD function, hill start assist and
ESP ®
trailer stabilisation are not available due to a malfunction.
The adaptive brake lights and COLLISION PREVENTION ASSIST
may also have failed.
In addition, the ÷ and å warning lamps light up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the
functions listed above.
The
braking distance may thus increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Drive on carefully.
X Visit a qualified specialist workshop. T!
÷
inoperative See
Owner's Manual EBD (electronic brake force distribution), ABS, ESP
®
, BAS, PRE-
SAFE ®
,

the HOLD function, hill start assist and ESP ®
trailer stabi-
lisation are unavailable due to a malfunction.
The adaptive brake lights and COLLISION PREVENTION ASSIST
may also have failed.
In addition, the ÷, å and ! warning lamps light up in
the instrument cluster and a warning tone sounds.
ATTENTION ASSIST is deactivated.
G WARNING
The brake system continues to function normally, but without the
functions listed above. The front and rear wheels could therefore
lock, for example, if you brake hard.
The

steerability and braking characteristics may be severely affec-
ted. The braking distance may increase in an emergency braking
situation.
If ESP ®
is not operational, ESP ®
is unable to stabilise the vehicle.
There is an increased danger of skidding and risk of an accident.
X Drive on carefully.
X Visit a qualified specialist workshop immediately.232
Display messages
On-board computer and displays