2018 MERCEDES-BENZ CLS brake sensor

of collision, you will be warned visually and
acoustically as well as by automatic braking.
i Pay attention to the important safety notes
in the "Driving safety systems" section
( Y
page 64).
PRE ‑ SAFE ®
Brake is only available in vehicles
with the Driving Assistance Plus package.
For PRE-SAFE ®
Brake to assist you when driving,
the radar sensor system and the camera system
must be switched on and be operational.
With the help of the radar sensor system and the
camera system, PRE-SAFE ®
Brake can detect
obstacles that are in front of your vehicle for an
extended period of time.
In addition, pedestrians in the path of your vehi-
cle can be detected.
PRE-SAFE ®
Brake detects pedestrians using
typical characteristics such as the body con-
tours and posture of a person standing upright.
i Observe the restrictions described in the
"Important safety notes" sec-
tion“ ( Y
page 73).
Important safety notes
G WARNING
PRE-SAFE ®
Brake will initially brake your vehi-
cle by a partial application of the brakes if a
danger of collision is detected. There may be
a collision unless you brake yourself. Even
after subsequent full application of the brakes
a collision cannot always be avoided, partic-
ularly when approaching at too high a speed.
There is a risk of an accident.
Always apply the brakes yourself and try to
take evasive action, provided it is safe to do
so.
In the event of a partial application of the brakes,
the vehicle is braked with up to 50% of the full
braking pressure.
G WARNING
PRE-SAFE ®
Brake cannot always clearly iden-
tify objects and complex traffic conditions. In these cases, PRE-SAFE ®
Brake may:R
give an unnecessary warning and then
brake the vehicle R
not give a warning or intervene
There is a risk of an accident.
Always pay particular attention to the traffic
situation and be ready to brake, especially if
PRE-SAFE ®
Brake warns you. Terminate the
intervention in a non-critical driving situation.
G WARNING
PRE-SAFE ®
Brake cannot always clearly iden-
tify people, especially if they are moving. In
these cases, PRE-SAFE ®
Brake cannot inter-
vene. There is a risk of an accident.
Always pay particular attention to the traffic
situation and be ready to brake, especially if
PRE-SAFE ®
Brake warns you.
In order to maintain the appropriate distance to
the vehicle in front and thus prevent a collision,
you must apply the brakes yourself.
G WARNING
PRE-SAFE ®
Brake does not react: R
to small people, e.g. children R
to animals R
to oncoming vehicles R
to crossing traffic R
when cornering
As a result, PRE-SAFE ®
Brake may neither
give warnings nor intervene in all critical sit-
uations. There is a risk of an accident.
Always pay careful attention to the traffic sit-
uation and be ready to brake.
In the event of snowfall or heavy rain, the rec-
ognition can be impaired.
Recognition by the radar sensor system is also
impaired if: R
there is dirt on the sensors or anything else
covering the sensors R
there is interference by other radar sources R
there are strong radar reflections, for exam-
ple in parking garagesDriving safety systems 73
Safety Z

R
a narrow vehicle is traveling in front, e.g. a
motorbike R
a vehicle is traveling in front on a different line
relative to the center of your vehicle
Recognition by the camera system is also
impaired in the event of: R
dirt on the camera or if the camera is covered R
glare on the camera system, e.g. from the sun
being low in the sky R
darkness R
or if: -
pedestrians move quickly, e.g. into the path
of the vehicle -
the camera system no longer recognizes a
pedestrian as a person due to special cloth-
ing or other objects -
a pedestrian is concealed by other objects -
the typical outline of a person is not distin-
guishable from the background
Following damage to the front end of the vehicle,
have the configuration and operation of the
radar sensors checked at a qualified specialist
workshop. This also applies to collisions at slow
speeds where there is no visible damage to the
front of the vehicle.
Following damage to the windshield, have the
configuration and operation of the camera sys-
tem checked at a qualified specialist workshop.
Function X
To activate/deactivate: activate or deacti-
vate PRE-SAFE ®
Brake in the on-board com-
puter ( Y
page 196).
If the PRE-SAFE ®
Brake is not activated, the

Notes on breaking-in a new vehicle
Important safety notes The sensor system of some driving and driving
safety systems adjusts automatically while a
certain distance is being driven after the vehicle
has been delivered or after repairs. Full system
effectiveness is not reached until the end of this
teach-in procedure.
New and replaced brake pads and discs only
reach their optimum braking effect after several
hundred kilometers of driving. Compensate for
this by applying greater force to the brake pedal.
The first 1000 miles (1500 km) The more you look after the engine when it is
new, the more satisfied you will be with its per-
formance in the future. R
You should therefore drive at varying vehicle
and engine speeds for the first 1000 miles
(1500 km). R
Avoid heavy loads, e.g. driving at full throttle,
during this period. R
Change gear in good time, before the tach-
ometer needle is

Do not use DISTRONIC PLUS while driving on
roads with steep gradients.
As DISTRONIC PLUS transmits radar waves, it
can resemble the radar detectors of the respon-
sible authorities. You can refer to the relevant
chapter in the Operator's Manual if questions
are asked about this.
i USA only: This device has been approved by
the FCC as a "Vehicular Radar System". The
radar sensor is intended for use in an auto-
motive radar system only. Removal, tamper-
ing, or altering of the device will void any war-
ranties, and is not permitted by the FCC. Do
not tamper with, alter, or use in any non-
approved way.
Any unauthorized modification to this device
could void the user's authority to operate the
equipment.
i Canada only: This device complies with
RSS-210 of Industry Canada. Operation is
subject to the following two conditions:
1. This device may not cause harmful inter-
ference, and
2. This device must accept any interference
received, including interference that may
cause undesired operation of the device.
Removal, tampering, or altering of the device
will void any warranties, and is not permitted.
Do not tamper with, alter, or use i n any non-
a
pproved way.
Any unauthorized modification to this device
could void the user's authority to operate the
equipment.
Important safety notes
G WARNING
DISTRONIC PLUS does not react to: R
people or animals R
stationary obstacles on the road, e.g. stop-
ped or parked vehicles R
oncoming and crossing traffic
As a result, DISTRONIC PLUS may neither give
warnings nor intervene in such situations.
There is a risk of an accident.
Always pay careful attention to the traffic sit-
uation and be ready to brake. G WARNING
DISTRONIC PLUS cannot always clearly iden-
tify other road users and complex traffic sit-
uations.
In such cases, DISTRONIC PLUS 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, in particular when warned to do so by
DISTRONIC PLUS.
G WARNING
DISTRONIC PLUS brakes your vehicle with up
to 50% of the maximum possible deceleration.
If this braking force is insufficient, DISTRONIC
PLUS warns you visually and audibly. There is
a risk of an accident.
In such cases, apply the brakes yourself and
try to take evasive action.
! When DISTRONIC PLUS or the HOLD func-
tion is activated, the vehicle brakes automat-
ically in certain situations.
To avoid damage to the vehicle, deactivate
DISTRONIC PLUS and the HOLD function in
the following or similar situations: R
when towing the vehicle R
in the car wash
DISTRONIC PLUS can neither reduce the risk of
an accident if you fail to adapt your driving style
nor override the laws of physics. DISTRONIC
PLUS cannot take account of road, weather and
traffic conditions. DISTRONIC PLUS 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.150
Driving system s
Dr ivi ng an d parking

4MATIC (permanent four-wheel drive) If you fail to adapt your driving style, 4MATIC can
neither reduce the risk of accident nor override
the laws of physics. 4MATIC cannot take
account of road, weather and traffic conditions.
4MATIC 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.
If a drive wheel spins due to insufficient grip: R
Only depress the accelerator pedal as far as
necessary when pulling away. R
Accelerate less when driving.
! Never tow the vehicle with one axle raised.
This may damage the transfer case. Damage
of this sort is not covered by the Mercedes-
Benz Limited Warranty. All wheels must
remain either on the ground or be fully raised.
Observe the instructions for towing the vehi-
cle with all wheels in full contact with the
ground.
i In wintry driving conditions, the maximum
effect of 4MATIC can only be achieved if you
use winter tires (M+S tires), with snow chains
if necessary.
4MATIC ensures that all four wheels are perma-
nently driven. Together with ESP ®
, it improves
the traction of your vehicle whenever a drive
wheel spins due to insufficient grip.
PARKTRONIC
Important safety notes PARKTRONIC is an electronic parking aid with
ultrasonic sensors. It monitors the area around
your vehicle using six sensors in the front
bumper and six sensors in the rear bumper.
PARKTRONIC indicates visually and audibly the
distance between your vehicle and an object.
PARKTRONIC 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. 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 maneuvering.
! When parking, pay particular attention to
objects above or below the sensors, such as flower pots or trailer drawbars. 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 on a truck
or a pneumatic drill could cause PARKTRONIC
to malfunction.
PARKTRONIC may not function correctly on
uneven terrain.
PARKTRONIC is activated automatically when
you: R
switch on the ignition R
shift the transmission to position D , R or NR
release the parking brake
PARKTRONIC is deactivated at speeds above
11 mph (18 km/h). It is reactivated at lower
speeds.
Range of the sensors
General notes PARKTRONIC does not take objects into con-
sideration that are: R
below the detection range, e.g. people, ani-
mals or objects. R
above the detection range, e.g. overhanging
loads, truck overhangs or loading ramps.
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 274).Driving systems 163
Driving and parking Z

This indicates that you have now reached the
minimum distance.
Deactivating/activating PARKTRONIC
C
Indicator lampD
Deactivates/activates PARKTRONIC If indicator lamp D lights up, PARKTRONIC is
deactivated. Active Parking Assist is then also
deactivated.
i PARKTRONIC is automatically activated
when you turn the SmartKey to position 2 in
the ignition lock.
Problems with PARKTRONIC Problem
Possible causes/consequences and P Solutions
Only the red segments in
the PARKTRONIC warn-
ing displays are lit. You
also hear a warning tone
for approximately two
seconds.
PARKTRONIC is then
deactivated and the indi-
cator lamp on the
PARKTRONIC button
lights up. PARKTRONIC has malfunctioned and has switched off. X
If problems persist, have PARKTRONIC checked at a qualified spe-
cialist workshop.
Only the red segments in
the PARKTRONIC warn-
ing displays are lit.
PARKTRONIC is then
deactivated. The PARKTRONIC sensors are dirty or there is interference. X
Clean the PARKTRONIC sensors ( Y
page 274).X
Switch the ignition back on.
The problem may be caused by an external source of radio or ultra-
sound waves. X
See if PARKTRONIC functions in a different location.
Active Parking Assist
General notes
Active Parking Assist is an electronic parking aid
with ultrasound. It measures the road on both
sides of the vehicle. A parking symbol indicates
a suitable parking space. Active steering inter-
vention and brake application can assist you during parking. You may also use PARKTRONIC
( Y
page 163).
Important safety notes
Active Parking Assist is merely an aid. It is not a
replacement for your attention to your immedi-
ate surroundings. You are always responsibleDriving systems 165
Driving and parking Z

vehicle are also monitored with the aid of the
radar sensor system. Active Lane Keeping
Assist detects lane markings on the road and
can warn you before you leave your lane unin-
tentionally. If you do not react to the warning, a
lane-correcting application of the brakes can
bring the vehicle back into the original lane.
This function is available in the range between
40 mph and 120 mph (60 km/h and 200 km/h).
For Active Lane Keeping Assist to assist you
when driving, the radar sensor system must be
operational
Important safety notes If you fail to adapt your driving style, Active Lane
Keeping Assist can neither reduce the risk of
accident nor override the laws of physics. Active
Lane Keeping Assist cannot take account of
road and weather conditions. It may not recog-
nize traffic situations. Active Lane Keeping
Assist 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.
Active Lane Keeping Assist cannot continuously
keep your vehicle in its lane.
G WARNING
Active Lane Keeping Assist cannot always
clearly detect lane markings.
In such cases, Active Lane Keeping Assist
can: R
give an unnecessary warning and then
make a course-correcting brake application
to the vehicle R
not give a warning or intervene
There is a risk of an accident.
Always pay particular attention to the traffic
situation and keep within the lane, especially
if Active Lane Keeping Assist alerts you. Ter-
minate the intervention in a non-critical driv-
ing situation.
The system may be impaired or may not function
if: R
there is poor visibility, e.g. due to insufficient
illumination of the road, or due to snow, rain,
fog or spray R
there is glare, e.g. from oncoming traffic, the
sun or reflections (e.g. when the road surface
is wet) R
the windshield is dirty, fogged up, damaged or
covered, for instance by a sticker, in the vicin-
ity of the camera R
the radar sensors in the front or rear bumpers
or the radiator trim are dirty, e.g. obscured by
snow R
there are no, several or unclear lane markings
for a lane, e.g. in areas with road construction
work R
the lane markings are worn away, dark or cov-
ered up, e.g. by dirt or snow R
the distance to the vehicle in front is too small
and the lane markings thus cannot be detec-
ted R
the lane markings change quickly, e.g. lanes
branch off, cross one another or merge R
the road is narrow and winding R
there are strong shadows cast on the road
If no vehicle is detected in the adjacent lane and
broken lane markings are detected, no lane-cor-
recting brake application is made.
Warning vibration in the steering wheel A warning may be given if a front wheel passes
over a lane marking. It will warn you by means of
intermittent vibration in the steering wheel for
up to 1.5 seconds.
Lane-correcting brake application
G WARNING
A lane-correcting brake application cannot
always bring the vehicle back into the original
lane. There is a risk of an accident.
Always steer, brake or accelerate yourself,
especially if Active Lane Keeping Assist warns
you or makes a lane-correcting brake appli-
cation.
G WARNING
Active Lane Keeping Assist only detects traf-
fic conditions or road users to a limited
extent. In very rare cases, the system may
make an inappropriate brake application, e.g.
after intentionally driving over a solid lane
marking. There is a risk of an accident.
An inappropriate brake application may be
interrupted at any time if you steer slightly in
the opposite direction. Always make sure thatDriving systems 185
Driving and parking Z

Display messages
Possible causes/consequences and P Solutions
' (US A only)
M (Canada only)
Check Brake Fluid
Level There is no t enough brak e fluid in th e brak e fluid reservoir .
In addition , th e ' (US A only) or M (Canada only) warning lamp
lights up in th e instrumen t cluste r and a warning tone sounds.
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 141).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 mbrace Inoperative On e or mor e main features of th e mbrace system are malfunctioning .X
Visit a qualified specialist workshop .
Collision Preven ‐
tio n Assist Plu s
Currently Unavaila‐
ble See Operator' s
Manual COLLISION PREVENTION ASSIST PLU S is temporarily no t operational.
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.
COLLISION PREVENTION ASSIST PLU S 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 141).X
Restart th e engine.
Collision Preven ‐
tio n Assist Plu s
Inoperative COLLISION PREVENTION ASSIST PLU S is temporarily inoperative due
to a malfunction . Adaptive Brake Assis t may also hav e failed.X
Visit a qualified specialist workshop .
PRE-SAFE
Inoperative See
Operator' s Manual Importan t function s of PRE-SAF E ®
hav e failed. Al l other occupant
safet y systems , e.g. air bags , remain available.X
Visit a qualified specialist workshop .206
Display messages
On-board computer and displays