2012 MERCEDES-BENZ A-CLASS HATCHBACK sensor

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,Tor
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 operationOn-board computer and displays

Further information on the distance warning
function (Y page 62).
Activating/deactivating ATTENTION
ASSIST X
Press the =or; button on the steer-
ing wheel to select the Assist.
Assist. menu.
X Press the 9or: button to select
ATTENTION ASSIST ATTENTION ASSIST.
X Press the abutton.
The current selection is displayed.
X To activate/deactivate: press thea
button again.
When ATTENTION ASSIST is deactivated,
the é symbol appears in the multifunc-
tion display in the assistance graphics dis-
play.
For further information about ATTENTION
ASSIST, see (Y page 195).
Activating/deactivating Blind Spot
Assist X
Press the =or; button on the steer-
ing wheel to select the Assist. Assist.menu.
X Press the 9or: button to select
Blind Spot Assist
Blind Spot Assist.
X Press the abutton.
The current selection is displayed.
X To activate/deactivate: press thea
button again.
For further information about Blind Spot
Assist, see (Y page 197).
When the Blind Spot Assist Sensors
Blind Spot Assist Sensors
deactivated
deactivated message is shown, the radar
sensors are deactivated.
X Switch on the radar sensor system
(Y page 223). Activating/deactivating Lane Keeping
Assist X
Press the =or; button on the steer-
ing wheel to select the Assist. Assist.menu.
X Press the 9or: button to select
Lane Keeping Assist Lane Keeping Assist.
X Press the abutton.
The current selection is displayed.
X Press ato confirm.
X Press the :or9 button to set Off
Off,
Standard
Standard orAdaptive
Adaptive .
X Press the abutton to save the setting.
When Lane Keeping Assist is activated, the
multifunction display shows the lane mark-
ings as bright lines in the assistance
graphic.
For further information about Lane Keeping
Assist, see (Y page 199). Service menu
In the
Serv. Serv. menu, you have the following
options:
R Calling up display messages in the mes-
sage memory (Y page 229)
R Restarting the tyre pressure loss warning
system (Y page 323)
R Calling up the service due date
(Y page 289) Menus and submenus
219On-board computer and displays Z

Activating/deactivating the interior light-
ing delayed switch-off
If you activate the Lighting delayed sw.-
Lighting delayed sw.-
off
off function, the interior lighting remains on
for 20 seconds after you remove the key from the ignition lock.
X Press the =or; button on the steer-
ing wheel to select the Settings Settingsmenu.
X Press the :or9 button to select the
Lights
Lights submenu.
X Press ato confirm.
X Press the :or9 button to select the
Lighting delayed sw.-off
Lighting delayed sw.-off function.
If the Lighting delayed sw.-off
Lighting delayed sw.-off func-
tion has been switched on, the vehicle inte-
rior is displayed in orange in the multifunc-
tion display.
X Press the abutton to save the setting.
Vehicle Setting permanent SPEEDTRONIC
X Press the =or; button on the steer-
ing wheel to select the Settings
Settingsmenu.
X Press the :or9 button to select the
Vehicle
Vehicle submenu.
X Press ato confirm.
X Press the :or9 button to select the
Limit
Limit speed
speed(winter
(winter tyres):
tyres):function.
You will see the current setting.
X Press ato confirm.
X Press the :or9 button to adjust
permanent SPEEDTRONIC in increments of
ten (230 km/h 230 km/h to160 km/h
160 km/h). The Off
Offset-
ting switches permanent SPEEDTRONIC
off.
X Press the abutton to store the entry.
Using the Limit speed (winter tyres)
Limit speed (winter tyres)
function, you can set permanent SPEED-
TRONIC (Y page 172). Switching the automatic locking feature
on/off
X Press the =or; button on the steer-
ing wheel to select the Settings Settingsmenu.
X Press the :or9 button to select the
Vehicle Vehicle submenu.
X Press ato confirm.
X Press the :or9 button to select the
Automatic door locks
Automatic door locks function.
When the Automatic door locks
Automatic door locks func-
tion is activated, the vehicle doors are dis-
played in orange in the multifunction dis-
play.
X Press the abutton to save the setting.
If you activate the Automatic door locks Automatic door locks
function, the vehicle is centrally locked above
a speed of around 15 km/h.
For further information on the automatic lock- ing feature, see (Y page 81).
Activating/deactivating the acoustic
locking confirmation
If you switch on the Acoustic AcousticLock
Lockfunction,
an acoustic signal sounds when you lock the
vehicle.
X Press the =or; button on the steer-
ing wheel to select the Settings
Settings menu.
X Press the :or9 button to select the
Vehicle Vehicle submenu.
X Press ato confirm.
X Press the :or9 button to select the
Acoustic Lock
Acoustic Lock function.
If the Acoustic
Acoustic Lock
Lockfunction is activated,
the & symbol in the multifunction dis-
play lights up orange.
X Press the abutton to save the setting.
Activating/deactivating the radar sensor
system
X Press the =or; button on the steer-
ing wheel to select the Settings
Settings menu.
X Press the :or9 button to select the
Vehicle Vehicle submenu.
X Press ato confirm. Menus and submenus
223On-board computer and displays Z

X
Press the 9or: button to select
Radar sensor (See Owner's Man.)
Radar sensor (See Owner's Man.).
You will see the selected setting: Activa‐
Activa‐
ted
ted orDeactivated
Deactivated.
X Press the abutton 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 Settingsmenu.
X Press the :or9 button to select
theHeating Heating submenu.
X Press ato confirm.
You will see the selected setting.
X Press ato confirm.
X Press the :or9 button to select A
A, B
B
or Change C
Change C.
X Press ato 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 :or9 button to set the
selected display.
X Press the abutton 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
Settings menu.
X Press the :or9 button to select the
Heating
Heating submenu.
X Press ato confirm.
You will see the selected setting.
X Press ato confirm. X
Press :or9 to select one of the
three departure times or Timer off Timer off(no
timer active).
X Press ato 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 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 submenusOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions PRE-SAFE
PRE-SAFE
Functions cur‐ Functions cur‐
rently rently
limited
limited See
See
Owner's Manual
Owner's Manual Adaptive Brake Assist is temporarily inoperative. Possible causes:
R the radar sensor cover in the radiator trim is dirty.
R the function is impaired due to heavy rain or snow.
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio sta-
tions or other sources of electromagnetic radiation.
R AMG vehicles: ESP ®
is deactivated.
R the system is outside the operating temperature range.
R the on-board voltage is too low.
Once the causes listed above no longer apply, the display message
goes out.
Adaptive Brake Assist is operational again.
If the display message does not disappear:
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 162).
X Clean the radar sensor cover in the radiator grille (Y page 294).
X Restart the engine.
X AMG vehicles: reactivate ESP ®
(Y page 66). PRE-SAFE PRE-SAFE
Functions limited Functions limited
See Owner's Manual See Owner's Manual Adaptive Brake Assist is faulty. The distance warning signal may
also have failed.
X Visit a qualified specialist workshop. ü If the symbol appears in the multifunction display, a seat belt
tongue has been inserted into a rear seat belt buckle.
Further information on the status indicator for the rear seat belts
(Y page 49). ý If the symbol appears in the multifunction display, a seat belt
tongue has not been inserted in a rear seat belt buckle.
G WARNING
A seat belt which is not worn correctly, or which has not been
engaged in the seat belt buckle correctly, cannot provide the
intended level of protection.
This poses an increased risk of injury.
X If necessary, ask the occupants in the rear to fasten their seat
belts (Y page 47).
Further information on the status indicator for the rear seat belts
(Y page 49). Display
messages
237On-board computer and displays Z

Display messages
Possible causes/consequences and
M
MSolutions b
Left tail lamp Left tail lamp
or
Right tail lamp
Right tail lamp The left or right-hand tail lamp is faulty.
X Check whether you are permitted to replace the bulb yourself
(Y page 112).
or
X Visit a qualified specialist workshop. b
Left daytime driv‐ Left daytime driv‐
ing lamp ing lamp
orRight
Right
daytime driving
daytime driving
lamp lamp The left-hand or right-hand daytime driving lamp is faulty.
X Check whether you are permitted to replace the bulb yourself
(Y page 112).
or
X Visit a qualified specialist workshop. b
Intell. Light Sys‐ Intell. Light Sys‐
tem inoperative tem inoperative The Intelligent Light System is faulty. The lights remain available
without the Intelligent Light System.
X Visit a qualified specialist workshop. b
Malfunction See Malfunction See
Owner's Manual Owner's Manual The exterior lighting is faulty.
X Visit a qualified specialist workshop. Vehicles with trailer tow hitch: a fuse may have blown.
X Check the fuses (Y page 314).
X If necessary, replace the blown fuse. Observe the warning notes
as you do so.
If the display message continues to be displayed: X Visit a qualified specialist workshop. b
AUTO AUTO
lights
lights inoper‐
inoper‐
ative
ative The light sensor is faulty.
X Visit a qualified specialist workshop. b
Switch off lights Switch off lights The lights are still switched on when you leave the vehicle. A
warning tone also sounds.
X Turn the light switch to Ã.242
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions Speed Limit Assist
Speed Limit Assist
Currently unavail‐ Currently unavail‐
able See Owner's able See Owner's
Manual Manual Speed Limit Assist is deactivated and temporarily inoperative.
Possible causes:
R the windscreen is dirty in the camera's field of vision.
R visibility is impaired due to heavy rain, snow or fog.
X Clean the windscreen.
If the system detects that the camera is fully operational, the dis-
play message disappears.
Speed Limit Assist is operational again. Speed Speed
Limit
LimitAssist:
Assist:
Unavailable in
Unavailable in
this country this country Speed Limit Assist is only available in certain countries.
X Drive on.
Speed Limit Assist is available again as soon as you drive into a
country in which its use is approved. Speed Speed
Limit
LimitAssist
Assist
inoperative
inoperative Speed Limit Assist is faulty.
X Visit a qualified specialist workshop. ë
Off Off The HOLD function is deactivated. the vehicle is skidding.
A warning tone also sounds.
X Reactivate the HOLD function later (Y page 179). The HOLD function is deactivated. When the brake pedal is firmly
depressed, an activation condition is not fulfilled.
A warning tone also sounds.
X Check the activation conditions for the HOLD function
(Y page 179). Radar sensor deac‐ Radar sensor deac‐
tivated See Own‐ tivated See Own‐
er's Manual er's Manual The radar sensor system is deactivated.
X Check whether or not the radar sensor system may be activated
(Y page 350).
X Switch on the radar sensor system (Y page 223).Radar sensor deac‐
Radar sensor deac‐
tivated tivated
autom.
autom.See
See
Owner's Manual
Owner's Manual Vehicles with a navigation system: the vehicle is close to a radio
telescope facility and is therefore prohibited from transmitting any
radar signals. The radar sensor system is deactivated automati-
cally.
If Blind Spot Assist was activated, it is no longer available. The
yellow 9indicator lamps also light up in the exterior mirrors.
X Drive on.
Blind Spot Assist is available again as soon as the vehicle is far
enough away from the radio telescope facility (Y page 350).246
Display
messagesOn-board computer and displays

Display messages
Possible causes/consequences and
M
MSolutions Vehicles with Becker
®
MAP PILOT: if the Becker ®
MAP PILOT is not
connected, the radar sensor system is deactivated automatically.
Blind Spot Assist is not available.
X Connect the Becker ®
MAP PILOT; see the separate operating
instructions. Lane Keeping
Lane Keeping
Assist currently Assist currently
unavailable See unavailable See
Owner's Manual Owner's Manual Lane Keeping Assist is deactivated and temporarily inoperative.
Possible causes:
R the windscreen is dirty in the camera's field of vision.
R visibility is impaired due to heavy rain, snow or fog.
R there are no lane markings for a longer period.
R the lane markings are worn, dark or covered, e.g. by dirt or snow.
Once the causes listed above no longer apply, the display message
goes out.
Lane Keeping Assist is operational again.
If the display message does not disappear:
X Pull over and stop the vehicle safely as soon as possible, paying
attention to road and traffic conditions.
X Secure the vehicle against rolling away (Y page 162).
X Clean the windscreen. Lane Keeping Lane Keeping
Assist inoperative Assist inoperative Lane Keeping Assist is faulty.
X Visit a qualified specialist workshop. Blind Spot Assist
Blind Spot Assist
currently unavail‐ currently unavail‐
able See Owner's able See Owner's
Manual Manual Blind Spot Assist is temporarily inoperative.
You have established the electrical connection between the trailer
and your vehicle.
X Press aon the steering wheel to confirm the display mes-
sage.
Blind Spot Assist is deactivated while towing a trailer. Display
messages
247On-board computer and displays Z