sensor MERCEDES-BENZ A-CLASS HATCHBACK 2015 Service Manual

Display messages
Possible causes/consequences and
M
MSolutions 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.
Possible causes:
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 the radar sensor system is outside the operating temperature
range
The yellow 9indicator lamps also light up in the exterior mir-
rors.
Once the causes listed above no longer apply, the display message goes out.
Blind Spot 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 Safeguard the vehicle against rolling away (Y page 184).
X Restart the engine. Active Blind Spot Active Blind Spot
Assist not availa‐ Assist not availa‐
ble when towing a ble when towing a
trailer See Own‐ trailer See Own‐
er's Manual er's Manual
. Blind Spot Assist is deactivated while towing a trailer.
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 Blind Spot Assist
inoperative inoperative Blind Spot Assist is faulty.
The yellow
9indicator lamps also light up in the exterior mir-
rors.
X Consult a qualified specialist workshop. Park Park
Assist
Assist cancel‐
cancel‐
led
led The driver's door is open and the driver's seat belt has not been
fastened.
X Repeat the parking process with the seat belt fastened and the
driver's door closed. You inadvertently touched the multifunction steering wheel while
steering intervention was active.
X While steering intervention is active, make sure not to touch the
multifunction steering wheel. The vehicle has started to skid and ESP
®
has intervened.
X Use Active Parking Assist again later (Y page 212). Display
messages
279On-board computer/Displays Z

Display messages
Possible causes/consequences and
M
MSolutions DISTRONIC
DISTRONIC
PLUS
PLUScur‐
cur‐
rently
rently unavailable
unavailable
See Owner's Manual
See Owner's Manual DISTRONIC PLUS is temporarily inoperative.
Possible causes:
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 the system is outside the operating temperature range
R the on-board voltage is too low.
A warning tone also sounds.
Once the causes listed above no longer apply, the display message goes out.
DISTRONIC PLUS 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 Safeguard the vehicle against rolling away (Y page 184).
X Restart the engine. DISTRONIC PLUS DISTRONIC PLUS
inoperative inoperative DISTRONIC PLUS is faulty. Adaptive Brake Assist may also have
failed.
A warning tone also sounds.
X Consult a qualified specialist workshop. DISTRONIC DISTRONIC
PLUS
PLUSsus‐
sus‐
pended
pended You have depressed the accelerator pedal. DISTRONIC PLUS is no
longer controlling the speed of the vehicle.
X Remove your foot from the accelerator pedal. DISTRONIC PLUS
DISTRONIC PLUS
- - - km/h - - - km/h An activation condition for DISTRONIC PLUS is not fulfilled.
X Check the activation conditions for DISTRONIC PLUS
(Y page 196). DISTRONIC
DISTRONIC
PLUS
PLUSand
and
SPEEDTRONIC inop‐
SPEEDTRONIC inop‐
erative erative DISTRONIC PLUS and SPEEDTRONIC are faulty. A warning tone
also sounds.
X Consult a qualified specialist workshop. Cruise Cruise
control
control and
and
SPEEDTRONIC inop‐
SPEEDTRONIC inop‐
erative erative SPEEDTRONIC and cruise control are malfunctioning.
A warning tone also sounds.
X Consult a qualified specialist workshop. Display
messages
281On-board computer/Displays Z

Display messages
Possible causes/consequences and
M
MSolutions Tyre press. moni‐
Tyre press. moni‐
tor currently tor currently
unavailable unavailable No signals can be received from the tyre pressure sensors due to
strong RF interference. The tyre pressure monitor is temporarily
malfunctioning.
X Drive on.
The tyre pressure monitor restarts automatically as soon as the
cause has been rectified. Wheel sensor(s) Wheel sensor(s)
missing missing There is no signal from the tyre pressure sensor of one or several
wheels. The pressure of the affected tyre is not displayed in the
multifunction display.
X Have the faulty tyre pressure sensor replaced at a qualified spe-
cialist workshop. Tyre press. moni‐ Tyre press. moni‐
tor tor
inoperative
inoperative No
No
wheel sensors
wheel sensors The wheels fitted do not have suitable tyre pressure sensors. The
tyre pressure monitor is deactivated.
X Fit wheels with suitable tyre pressure sensors.
The tyre pressure monitor is activated automatically after driv-
ing for a few minutes. Tyre press. moni‐ Tyre press. moni‐
tor inoperative tor inoperative The tyre pressure monitor is faulty.
X Consult a qualified specialist workshop. Vehicle
Display messages
Possible causes/consequences and
M
MSolutions Depress brake to
Depress brake to
start engine start engine You have attempted to start the engine with the transmission in
position
Nwithout depressing the brake pedal.
X Depress the brake pedal. To shift out of P To shift out of P
or N, depress or N, depress
brake and start brake and start
engine engine You have attempted to shift the transmission to position
Ror D
without starting the engine.
X Start the engine.
X Depress the brake pedal.
i It is only possible to shift the transmission from position
Pto
the desired position if you depress the brake pedal. Only then
can the parking lock be deactivated. If you do not depress the
brake pedal, the DIRECT SELECT lever can still be moved but the parking lock remains engaged.
i At transmission fluid temperatures below
Ò20 † you can only
shift out of position Pinto another transmission position when
the engine is running. Display
messages
285On-board computer/Displays Z

Engine
Problem
Possible causes/consequences and
M
MSolutions ;
The yellow engine diag-
nostics warning lamp
lights up while the
engine is running. There may be a fault, for example:
R in the engine management
R in the fuel injection system
R in the exhaust system
R in the ignition system (for vehicles with petrol engines)
R in the fuel system
The emission limit values may be exceeded and the engine may be running in emergency mode.
X Consult a qualified specialist workshop immediately. Vehicles with a diesel engine: the fuel tank has been run dry
(Y
page 183).
X Start the engine three to four times after refuelling.
If the yellow engine diagnostics warning lamp goes out, emer-
gency running mode is cancelled. The vehicle need not be
checked. æ
The yellow reserve fuel
warning lamp is on
while the engine is run-
ning.
The fuel level has dropped into the reserve range.
Operation of the auxiliary heating is deactivated if the fuel level
drops into the reserve range.
X Refuel at the nearest filling station. ?
The red coolant warn-
ing lamp lights up while
the engine is running
and the coolant tem-
perature gauge is at the start of the scale. The temperature sensor for the coolant temperature gauge is
faulty.
The coolant temperature is no longer being monitored. There is a risk of engine damage if the coolant temperature is too high.
X Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine. Do not continue driving
under any circumstances.
X Safeguard the vehicle against rolling away (Y page 184).
X Consult a qualified specialist workshop. Warning and indicator lamps in the instrument cluster
301On-board computer/Displays Z

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
windscreen and the rear window at regular
intervals. Deposits such as leaves, petals
and pollen may under certain circumstan-
ces prevent water from draining away. This
can lead to corrosion damage and damage to electronic components.
X Clean the inside and outside of the win-
dows with a damp cloth and a cleaning
agent that is recommended and approved
by Mercedes-Benz.
Cleaning the wiper blades G
WARNING
If the windscreen wipers are set in motion
when cleaning the windscreen or wiper
blades, you could become trapped. There is a danger of injury.
Always switch off the windscreen wipers and
the ignition before cleaning the windscreen or wiper blades.
! Only fold the windscreen wipers away
from the windscreen when vertical. Other-
wise, you will damage the bonnet.
! Do not pull on 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.
! Hold the wiper arm securely when folding
back. The windscreen could be damaged if
the wiper arm hits against it suddenly.
X Fold the wiper arms away from the wind-
screen.
X Clean the wiper blades carefully using a
damp cloth.
X Fold the windscreen wipers back again
before switching on the ignition. Cleaning the exterior lighting !
Only use cleaning agents or cleaning
cloths that are suitable for plastic lenses.
Unsuitable cleaning agents or cleaning
cloths could scratch or damage the plastic lenses of the exterior lighting.
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.
Cleaning the mirror turn signal !
Only use cleaning agents or cleaning
cloths that are suitable for plastic lenses.
Unsuitable cleaning agents or cleaning
cloths could scratch or damage the plastic lenses of the mirror turn signals.
X Clean the plastic lenses of the mirror turn
signals in the exterior mirror housing using
a wet sponge and mild cleaning agent, e.g.
Mercedes-Benz car shampoo or cleaning
cloths.
Cleaning the sensors !
If you clean the sensors with a high-pres-
sure cleaner, make sure that you keep a
distance of at least 30 cm between the
vehicle and the high-pressure cleaner noz-
zle. Information about the correct distance is available from the equipment manufac-
turer. 332
CareMaintenance and care

X
Clean sensors :of the driving systems
with water, car shampoo and a soft cloth.
Cleaning the reversing camera !
Do not clean the camera lens and the area
around the reversing camera with a high-
pressure cleaner. X
Make sure that the vehicle is stationary and
that the key is in position 2in the ignition
lock.
X Open the camera cover for cleaning using
COMAND Online or Audio 20 (see separate
operating instructions).
X To clean the reversing camera: use clean
water and a soft cloth to clean camera
lens :. Cleaning the exhaust tail pipes G
WARNING
The exhaust tail pipe and tail pipe trim can
become very hot. If you come into contact
with these parts of the vehicle, you could burn
yourself. There is a risk of injury.
Always be particularly careful around the
exhaust tail pipe and the tail pipe trim. Allow
these components to cool down before touch-
ing them.
! Do not clean the exhaust pipe with acid-
based cleaning agents, such as sanitary
cleanser or wheel cleaner.
! Mercedes-AMG vehicles with black
exhaust pipes: the black-chrome tailpipe
finishers should not be polished with a
chrome polish. They will otherwise lose
their black sheen. For optimal care, the fin- ishers should be rubbed with a lightly oiled
cloth after every car wash. Commercially
available engine and care oils are suitable
for this.
For heavier soiling, you can apply a fine
paintwork polish with a microfibre cloth.
Remove the excess polish residue after pol- ishing.
Impurities combined with the effects of road
grit and corrosive environmental factors may cause flash rust to form on the surface. You
can restore the original shine of the exhaust
pipe by cleaning it regularly, especially in win- ter and after washing the vehicle.
X Clean the exhaust pipe with a care product
tested and approved by Mercedes-Benz.
Cleaning the trailer tow hitch H
Environmental note
Dispose of oily and greasy cloths in an envi-
ronmentally-responsible manner.
! Do not clean the ball coupling with a high-
pressure cleaner. Do not use solvents. Care
333Maintenance and care Z

Restarting the tyre pressure loss warn-
ing system Restart the tyre pressure loss warning system
if you have:
R changed the tyre pressure
R changed the wheels or tyres
R fitted new wheels or tyres
X Before restarting, make sure that the tyre
pressures are set properly on all four tyres
for the respective operating conditions.
The recommended tyre pressures can be
found in the tyre pressure table on the fuel
filler flap.
The tyre pressure loss warning system can only give reliable warnings if you have set
the correct tyre pressure. If an incorrect
tyre pressure is set, these incorrect values
will be monitored.
X Observe the notes in the section on tyre
pressures (Y page 362).
X Make sure that the key is in position 2in the
ignition lock (Y page 157).
X Press =or; on the steering wheel
to select the Serv.
Serv.menu.
X Press the 9or: button to select
Tyre pressure
Tyre pressure .
X Press the abutton.
The Run Flat Indicator active Run Flat Indicator active
Restart
Restart with
withOK
OKmessage appears in the
multifunction display.
If you wish to confirm the restart: X Press the abutton.
The Tyre press. now OK?
Tyre press. now OK? message
appears in the multifunction display.
X Press the 9or: button to select
Yes
Yes.
X Press the abutton.
The Run Flat Indicator restarted
Run Flat Indicator restarted
message appears in the multifunction dis-
play.
After a teach-in period, the tyre pressure
loss warning system will monitor the set
tyre pressures of all four tyres. If you wish to cancel the restart:
X Press the %button.
or X If the Tyre press. now OK?
Tyre press. now OK? message
appears, press the 9or: button to
select Cancel Cancel.
X Press the abutton.
The tyre pressure values stored at the last
restart will continue to be monitored. Tyre pressure monitor
General notes If a tyre pressure monitor system is fitted, the
vehicle's wheels have sensors fitted that
monitor the tyre pressures in all four tyres.
The tyre pressure monitor warns you if the
pressure drops in one or more of the tyres.
The tyre pressure monitor only functions if
the corresponding sensors are fitted to all
wheels.
Information on tyre pressures is shown in the multifunction display. After a few minutes of
driving, the current tyre pressure of each tyre
is shown in the Serv. Serv.menu of the multifunc-
tion display, see illustration (example). For further information on displaying this
message, refer to the "Checking the tyre pres-
sure electronically" section (Y page 365).
Important safety notes It is the driver's responsibility to set the tyre
pressure to the recommended cold tyre pres-
sure suitable for the operating situation
(Y page 362). Note that the correct tyre pres-
sure for the current operating situation must
first be taught-in to the tyre pressure monitor. 364
Tyre pressureWheels and tyres

If there is a substantial loss of pressure, the
warning threshold for the warning message is aligned to the reference values taught-in.
Restart the tyre pressure monitor after
adjusting to the cold tyre pressure
(Y page 366). The current pressures are
saved as new reference values. This will
ensure that a warning message will only
appear if the tyre pressure drops significantly.
The tyre pressure monitor does not warn you of an incorrectly set tyre pressure. Observe
the notes on the recommended tyre pressure
(Y page 362).
The tyre pressure monitor is not able to warn you of a sudden loss of pressure, e.g. if the
tyre is penetrated by a foreign object. In the
event of a sudden loss of pressure, bring the
vehicle to a halt by braking carefully. Avoid
abrupt steering manoeuvres.
The tyre pressure monitor has a yellow warn-
ing lamp in the instrument cluster for indicat-
ing a pressure loss or malfunction. Depending on how the warning lamp flashes or lights up,
a tyre pressure that is too low or a malfunc-
tion in the tyre pressure monitor is indicated:
R if the warning lamp is lit continuously, the
tyre pressure on one or more tyres is sig-
nificantly too low. The tyre pressure moni-
tor is not malfunctioning.
R if the warning lamp flashes for around a
minute and then remains lit constantly, the
tyre pressure monitor is malfunctioning.
In addition to the warning lamp, a message
appears in the multifunction display. Observe
the information on display messages
(Y page 283).
It may take up to ten minutes for a malfunc-
tion of the tyre pressure monitor to be indi-
cated. A malfunction will be indicated by the
tyre pressure warning lamp flashing for
approximately one minute and then remain-
ing lit. When the fault has been rectified, the
tyre pressure warning lamp goes out after you
have driven for a few minutes.
The tyre pressure values indicated by the on- board computer may differ from those meas- ured at a filling station using a pressure
gauge. The tyre pressures shown by the on-
board computer refer to those measured at
sea level. At high altitudes, the tyre pressure
values indicated by a pressure gauge are
higher than those shown by the on-board
computer. In this case, do not reduce the tyre
pressures.
The operation of the tyre pressure monitor
can be affected by interference from radio
transmitting equipment (e.g. radio head-
phones, two-way radios) that may be being
operated in or near the vehicle.
Checking the tyre pressure electroni-
cally X
Make sure that the key is in position 2in the
ignition lock (Y page 157).
X Press =or; on the steering wheel
to select the Serv.
Serv.menu.
X Press the 9or: button to select
Tyre pressure Tyre pressure.
X Press the abutton.
The current tyre pressure for each wheel
will be displayed in the multifunction dis-
play.
If the vehicle was parked for longer than
20 minutes, the Tyre Tyrepressures
pressures will
willbe
be
displayed after a few minutes of
displayed after a few minutes of
driving driving message is shown.
After a teach-in period, the tyre pressure
monitor automatically detects new wheels or
new sensors. As long as a clear allocation of
the tyre pressure values to the individual
wheels is not possible, the Tyre pressure Tyre pressure
monitor active
monitor active message is shown instead
of the tyre pressure display. The tyre pres-
sures are already being monitored.
If an emergency spare wheel is fitted, for a
few minutes the system may continue to
show the tyre pressure of the wheel that has been removed. If this occurs, note that the
value displayed for the position where the
spare wheel is fitted is not the same as the
current tyre pressure of the emergency spare wheel. Tyre pressure
365Wheels and tyres Z

X
Clean the wheel and wheel hub contact
surfaces.
X Place the new wheel on the wheel hub and
push it on.
X Tighten the wheel bolts until they are fin-
ger-tight.
Lowering the vehicle G
WARNING
The wheels could work loose if the wheel nuts and bolts are not tightened to the specified
tightening torque. There is a risk of accident.
Have the tightening torque immediately
checked at a qualified specialist workshop
after a wheel is changed.
X Place the ratchet ring spanner onto the
hexagon nut of the jack so that the letters
AB are visible.
X Turn the ratchet ring spanner until the vehi-
cle is once again standing firmly on the
ground.
X Place the jack to one side. X
Tighten the wheel bolts evenly in a cross-
wise pattern in the sequence indicated ( :
to A). The specified tightening torque is
130 Nm .
X Turn the jack back to its initial position.
X Stow the jack and the rest of the vehicle
tools in the vehicle again.
X Mercedes-AMG vehicles and vehicles
with AMG equipment: insert the cover
into the outer sill.
X Check the air pressure of the newly fitted
wheel and adjust accordingly.
Observe the recommended tyre pressure
(Y page 362).
If you are driving with the emergency spare
wheel fitted, the tyre pressure loss warning
system or the tyre pressure monitor cannot
function reliably. Only restart the tyre pres-
sure loss warning system or tyre pressure
monitor when the defective wheel has been
replaced with a new wheel.
Vehicles with a tyre pressure monitor: all
fitted wheels must be equipped with func-
tioning sensors. Wheel and tyre combinations
General notes
! For safety reasons, Mercedes-Benz rec-
ommends that you only use tyres and
wheels which have been approved by
Mercedes-Benz specifically for your vehi-
cle.
These are specially adapted to the control
systems, such as ABS or ESP ®
and are
marked as follows:
R MO = Mercedes-Benz Original
R MOE = Mercedes-Benz Original Extended
(tyres featuring run-flat characteristics)
R MO1 = Mercedes-Benz Original (only cer-
tain AMG tyres)
Mercedes-Benz Original Extended tyres
may only be used on wheels that have been
specifically approved by Mercedes-Benz. 372
Wheel and tyre combinationsWheels and ty
res

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). Information on technical data
i The technical data was determined in
accordance with EU Directives. All data
applies to the vehicle's standard equip-
ment. The data may therefore differ for
vehicles with optional equipment. You can
obtain further information from a
Mercedes-Benz Service Centre. Vehicle electronics
Tampering with the engine electron-
ics
! Only have work carried out on the engine
electronics and its associated parts, such
as control units, sensors, actuating com-
ponents and connector leads, at a qualified specialist workshop. Vehicle components
may otherwise wear more quickly and the
vehicle's operating permit may be invalida-
ted. Retrofitting two-way radios and
mobile phones (RF transmitters) G
WARNING
If RF transmitters are tampered with or not
properly retrofitted, the electromagnetic radi- ation they emit can interfere with the vehicle
electronics. This may jeopardise the opera- tional safety of the vehicle. There is a risk of an
accident.
You should have all work on electrical and
electronic components carried out at a quali-
fied specialist workshop. G
WARNING
If you operate RF transmitters incorrectly in
the vehicle, the electromagnetic radiation
could interfere with the vehicle electronics,
e.g.:
R if the RF transmitter is not connected to an
exterior aerial
R the exterior aerial has been fitted incor-
rectly or is not a low-reflection type
This could jeopardise the operating safety of
the vehicle. There is a risk of an accident.
Have the low-reflection exterior aerial fitted at
a qualified specialist workshop. When oper-
ating RF transmitters in the vehicle, always
connect them to the low-reflection exterior
aerial.
! The operating permit may be invalidated if
the instructions for installation and use of
RF transmitters are not observed.
In particular, the following conditions must be complied with:
R only approved wavebands may be used.
R observe the maximum permissible out-
put in these wavebands.
R only approved aerial positions may be
used.
Excessive levels of electromagnetic radiation
may cause damage to your health and to the
health of others. The use of an exterior aerial
takes into consideration the scientific discus- sion surrounding the possible health risk
posed by electromagnetic fields.
Observe the notes on operating mobile
phones (Y page 318).
The following aerial positions may be used for
the correct installation of RF transmitters: 394
Vehicle electronicsTechnical data