2017 MERCEDES-BENZ CLA brake sensor

In such cases, Distance Pilot DISTRONIC may: R
give an unnecessary warning and then
brake the vehicle R
neither give a warning nor intervene R
accelerate or brake unexpectedly
There is a risk of an accident.
Continue to drive carefully and be ready to
brake, especially if Distance Pilot DISTRONIC
warns you.
G WARNING
Distance Pilot DISTRONIC brakes your vehicle
with up to 50% of the maximum possible
deceleration. If this deceleration is not suffi-
cient, Distance Pilot DISTRONIC alerts you
with a visual and acoustic warning. There is a
risk of an accident.
Apply the brakes yourself in these situations
and try to take evasive action.
! When Distance Pilot DISTRONIC or the
HOLD function is activated, the vehicle
brakes automatically in certain situations.
To avoid damage to the vehicle, deactivate
Distance Pilot DISTRONIC and the HOLD
function in the following or similar situations: R
when towing the vehicle R
in the car wash
If you fail to adapt your driving style, Distance
Pilot DISTRONIC can neither reduce the risk of
an accident nor override the laws of physics.
Distance Pilot DISTRONIC cannot take into
account road, weather or traffic conditions. Dis-
tance Pilot DISTRONIC is only an aid. You are
responsible for the distance to the vehicle in
front, for vehicle speed, for braking in good time
and for staying in your lane.
Do not use Distance Pilot DISTRONIC: R
in road and traffic conditions which do not
allow you to maintain a constant speed, e.g. in
heavy traffic or on winding roads R
on slippery road surfaces. Braking or accel-
erating could cause the drive wheels to lose
traction and the vehicle could then skid R
when there is poor visibility, e.g. due to fog,
heavy rain or snow Distance Pilot DISTRONIC may not detect nar-
row vehicles driving in front, e.g. motorcycles, or
vehicles driving on a different line.
In particular, the detection of obstacles can be
impaired if: R
there is dirt on the sensors or anything else
covering the sensors R
there is snow or heavy rain R
there is interference by other radar sources R
there are strong radar reflections, for exam-
ple, in parking garages
If Distance Pilot DISTRONIC no longer detects a
vehicle in front, it may unexpectedly accelerate
to the speed stored.
This speed may: R
be too high if you are driving in a filter lane or
an exit la ne R
be so high when driving in the right-hand lane
that you overtake vehicles in the left-hand
lane R
be so high in the left lane that you pass vehi-
cles driving in the right lane
If there is a change of drivers, advise the new
driver of the speed stored.
Cruise control lever
C
Stores the current speed or a higher speed
D
Stores the current speed or a lower speed

Parking Assist PARKTRONIC
Important safety notes Parking Assist PARKTRONIC is an electronic
parking aid with ultrasound. It monitors the area
around your vehicle using six sensors in the
front bumper and six sensors in the rear
bumper. Parking Assist PARKTRONIC visually
and audibly indicates the distance between your
vehicle and an object.
Parking Assist PARKTRONIC is only an aid. It is
not a replacement for your attention to your
immediate surroundings. You are always
responsible for safe maneuvering, parking and
exiting a parking space. When maneuvering,
parking or pulling out of a parking space, make
sure that there are no persons, animals or
objects in the area in which you are maneuver-
ing.
! When parking, pay particular attention to
objects above or below the sensors, such as
flower pots or trailer drawbars. Parking Assist
PARKTRONIC does not detect such objects
when they are in the immediate vicinity of the
vehicle. You could damage the vehicle or the
objects.
The sensors may not detect snow and other
objects that absorb ultrasonic waves.
Ultrasonic sources such as an automatic car
wash, the compressed-air brakes of a truck or
a pneumatic drill could cause Parking Assist
PARKTRONIC to malfunction.
Parking Assist PARKTRONIC may not function
correctly on uneven terrain.
Parking Assist PARKTRONIC is activated auto-
matically when you: R
switch on the ignition R
shift the transmission to position D , R or NR
release the electric parking brake
Parking Assist PARKTRONIC is deactivated at
speeds above 11 mph (18 km/h). It is reactiva-
ted at lower speeds. Range of the sensors General notes Parking Assist PARKTRONIC does not take into
account obstacles located: R
below the detection range, e.g. people, ani-
mals or objects. R
above the detection range, e.g. overhanging
loads, tail sections or loading ramps of goods
vehicles.
C
Sensors in the front bumper, left-hand side
(example)
The sensors must be free from dirt, ice or slush.
They can otherwise not function correctly. Clean
the sensors regularly, taking care not to scratch
or damage them ( Y
page 262).
Range
C
Detection range of front sensors
D
Detection range of rear sensors160
Driving systems
Driving and parking

i Parking Assist PARKTRONIC is automati-
cally activated when you turn the SmartKey to
position 2 in the ignition lock.
Problems with Parking Assist PARKTRONIC Problem
Possible causes/consequences and P Solutions
Only the red segments in
the Parking Assist
PARKTRONIC warning
displays are lit. You also
hear a warning tone for
approximately two sec-
onds.
Parking Assist
PARKTRONIC is then
deactivated and the indi-
cator lamp on the
PARKTRONIC button
lights up. Parking Assist PARKTRONIC has malfunctioned and has been deacti-
vated. X
If problems persist, have Parking Assist PARKTRONIC checked at a
qualified specialist workshop.
Only the red segments in
the Parking Assist
PARKTRONIC warning
displays are lit. Parking
Assist PARKTRONIC is
then deactivated. The Parking Assist PARKTRONIC sensors are dirty or there is inter-
ference. X
Clean the Parking Assist PARKTRONIC sensors ( Y
page 262).X
Switch the ignition back on.
The problem may be caused by an external source of radio or ultra-
sound waves. X
Check to see if Parking Assist PARKTRONIC works at a different
location.
Parking Pilot
General notes Parking Pilot is an electronic parking aid with
ultrasound. It measures the road on both sides
of the vehicle. A parking symbol indicates a suit-
able parking space. Active steering intervention
and brake application can assist you during
parking and when exiting a parking space. Park-
ing Assist PARKTRONIC is also available
( Y
page 160).
Important safety notes
Parking Pilot is only an aid. It is not a replace-
ment for your attention to your immediate sur-
roundings. You are always responsible for safe
maneuvering, parking and exiting a parking
space. Make sure that no persons, animals or
objects are in the maneuvering range. When Parking Assist PARKTRONIC is deactiva-
ted, Parking Pilot is also unavailable.
G WARNING
While parking or pulling out of a parking
space, the vehicle swings out and can drive
onto areas of the oncoming lane. This could
result in a collision with another road user.
There is a risk of an accident.
Pay attention to other road users. Stop the
vehicle if necessary or cancel the Parking Pilot
parking procedure.
! If unavoidable, you should drive over obsta-
cles such as curbs slowly and not at a sharp
angle. Otherwise, you may damage the
wheels or tires.162
Driving systems
Driving and parking

Display messages
Possible causes/consequences and P Solutions
The yellow $ warning lamp lights up and th e red I (US A only)
or $ (Canada only) indicator lamp flashes .
It is no t possibl e to apply th e electric parking brak e manually.X
Shift th e transmission to position P .X
Visit a qualified specialist workshop .
' (USA
only)
M ( Canada
only)
Check Brake Fluid
Level There is no t enough brak e fluid in th e brak e fluid reservoir .
A warning tone sounds. The ' (US A only) or M (Canada only)
warning lamp s in th e instrumen t cluste r may also ligh t up.
G WARNIN G
The braking effec t may be impaired.
There is a ris k of an accident.X
Pull ove r and stop th e vehicl e safely as soo n as possible, payin g
attention to roa d and traffic conditions. Do no t continu e drivin g
under any circumstances. X
Secur e th e vehicl e against rollin g away ( Y
page 140).X
Consult a qualified specialist workshop .X
Do no t add brak e fluid . This does no t correc t th e malfunction .
& Check Brake Pad Wea r The brak e pads/linings hav e reached their wear limit.X
Visit a qualified specialist workshop .
S Inoperative On e or mor e main features of th e mbrace system are malfunctioning .X
Visit a qualified specialist workshop .
Active Brake Assist
Functions Currently
Limite d See Opera‐
tor's Manual Active Brake Assis t is temporarily inoperative.
Possibl e causes are: R
th e radar sensor system is temporarily inoperative, e.g. due to elec -
tromagneti c radiation emitted by nearby TV or radi o station s or
other source s of electromagneti c radiationR
th e system is outside th e operating temperature rangeR
th e on-boar d voltag e is to o low
Whe n th e causes state d abov e no longer apply, th e display message
disappears.
Active Brake Assis t is operational again .
If th e display message does no t disappear :X
Pull ove r and stop th e vehicl e safely as soo n as possible, payin g
attention to roa d and traffic conditions.X
Secur e th e vehicl e against rollin g away ( Y
page 140).X
Restart th e engine.
Active Brake
Assist : System Inop‐
erativ e Active Brake Assis t is unavailable due to a malfunction . Situation -
dependen t parking assistanc e may also hav e failed.X
Visit a qualified specialist workshop immediately.194
Display messages
On-board computer and displays

Display messages
Possible causes/consequences and P Solutions
Radar Sensor s Dirty
See Operator' s Man ‐
ual The radar sensor system is malfunctioning .
Possibl e causes are: R
Dirt on sensor sR
Heavy rain or snow R
Whe n drivin g on inter-urban roads without traffic or infrastructure,
e.g. in desert-like area s
At least on e drivin g system or drivin g safet y system is malfunctioning
or is temporarily unavailable :R
Active Brake Assis tR
Distanc e Pilo t DISTRONI C
A warning tone also sounds.
Once th e caus e of th e problem is no longer present, th e drivin g and
drive safet y systems will be available again . The display message dis-
appears.
If th e display message does no t disappear :X
Pull ove r and stop th e vehicl e safely as soo n as possible, payin g
attention to roa d and traffic conditions.X
Secur e th e vehicl e against rollin g away ( Y
page 140).X
Switc h off th e engine.X
Clean all sensor s ( Y
page 262).X
Restart th e engine.
The display message disappears.
u SRS Malfunction Ser ‐
vic e Required The restrain t system is malfunctioning . The u warning lamp also
lights up in th e instrumen t cluster.
G WARNIN G
The air bags or Emergency Tensioning Devices may either be triggered
unintentionally or, in th e event of an accident, may no t be triggered .
There is an increased ris k of injury.X
Visit a qualified specialist workshop immediately.
Fo r further information about th e restrain t system, see ( Y
page 39) .
u Front Lef t Malfunc‐
tio n Servic e
Required or Front
Right Malfunction
Servic e Required The restrain t system is malfunctioning at th e fron t on th e lef t or right .
The u warning lamp also lights up in th e instrumen t cluster.
G WARNIN G
The air bags or Emergency Tensioning Devices may either be triggered
unintentionally or, in th e event of an accident, may no t be triggered .
There is an increased ris k of injury.X
Visit a qualified specialist workshop immediately. Display messages 19 5
On-board computer and displays Z

Display messages
Possible causes/consequences and P Solutions
TirePress . Sen ‐
sor(s) Missin g US A only:
There is no signal from th e tire pressur e sensor of on e or several
wheels. The pressur e of th e affecte d tire does no t appear in th e mul-
tifunction display. X
Hav e th e fault y tire pressur e sensor replace d at a qualified special -
ist workshop .
Tir e Pressure Moni‐
tor Inoperative No
Wheel Sensor s US A only:
The wheels mounte d do no t hav e a suitable tire pressur e sensor . The
tire pressur e monitor is deactivated. X
Moun t wheels wit h suitable tire pressur e sensors.
The tire pressur e monitor is activated automatically after drivin g for
a few minutes.
Tir e Press. Monito r
Inoperative US A only:
The tire pressur e monitor is faulty.X
Visit a qualified specialist workshop .
Vehicle Display messages
Possible causes/consequences and P Solutions
Depres s Brake to
Start Engine You hav e attempte d to start th e engin e wit h th e transmission in posi-
tion N without depressing th e brak e pedal .X
Depress th e brak e pedal .
To Deselect P or N,
Depres s Brake and
Start Engine You hav e attempte d to shift th e transmission to position R or D with-
out starting th e engine.X
Start th e engine. X
Depress th e brak e pedal .
i It is only possibl e to shift th e transmission from position P to th e
desire d position if you depress th e brak e pedal . Only then can th e
parking loc k be deactivated. If you do no t depress th e brak e pedal ,
th e DIRECT SELECT lever can still be moved but th e parking loc k
remain s engaged.
i At transmission fluid temperatures belo w