rain sensor MERCEDES-BENZ S-Class 2012 W221 User Guide

conditions. Additionally, the driver must
provide the steering, braking and other driving
inputs necessary to remain in control of the
vehicle.
High-frequency sources such as toll stations,
speed measuring systems etc. can cause the
DISTRONIC PLUS system to temporarily
cease functioning.GWARNING
The DISTRONIC PLUS cannot take road and
traffic conditions into account. Only use the
DISTRONIC PLUS if the road, weather and
traffic conditions make it advisable to travel
at a constant speed.
GWARNING
Use of the DISTRONIC PLUS can be
dangerous on slippery roads. Rapid changes
in tire traction can result in wheel spin and
loss of control.
The DISTRONIC PLUS does not function in
adverse sight and distance conditions. Do not
use the DISTRONIC PLUS during conditions of
fog, heavy rain, snow or sleet.
GWARNING
The DISTRONIC PLUS cannot take weather
conditions into account. Switch off the
DISTRONIC PLUS or do not switch it on if:
R roads are slippery or covered with snow or
ice. The wheels could lose traction while
braking or accelerating, and the vehicle
could skid.
R the DISTRONIC PLUS system sensor covers
are dirty or visibility is diminished due to
snow, rain or fog, for example. The distance
control system functionality could be
impaired.
Always pay attention to surrounding traffic
conditions even while the DISTRONIC PLUS is
switched on. Otherwise, you may not be able
to recognize dangerous situations until it is
too late. This could cause an accident in which
you and/or others could be injured.
GWARNING
The "Resume" function should only be
operated if the driver is fully aware of the
previously set speed and wishes to resume
this particular preset speed.
GWARNING
Your undivided attention to street and traffic
conditions is necessary at all times whether
DISTRONIC PLUS is active or not.
The use of DISTRONIC PLUS can be
dangerous on winding roads or in heavy traffic
because conditions do not allow safe driving
at a constant speed.
DISTRONIC PLUS does not react to stationary
objects on the road (for example, a vehicle
stopped in traffic or an abandoned vehicle).
DISTRONIC PLUS likewise does not react to
oncoming vehicles.
Deactivate DISTRONIC PLUS:
R when changing to the right lane, if the
vehicles in the left lane are driving slower
R when driving into a filter lane or an
expressway exit
R in complex driving situations, for example
in construction sites on an expressway
In these situations DISTRONIC PLUS will
maintain the set speed if it is not deactivated.
DISTRONIC PLUS is intended only for
maintaining a set speed and a set distance
from the objects moving in front of the
vehicle.
GWARNING
An intermittent warning sounds and the
distance warning lamp · in the instrument
cluster is illuminated if the DISTRONIC PLUS
system calculates that the distance to the
vehicle ahead and your vehicle's current
speed indicate that the DISTRONIC PLUS will
not be capable of slowing the vehicle
sufficiently to maintain the preset following
distance, which creates a danger of a
collision.
334Driving systemsDriving and parking

! 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.
Minimum distanceCenterApproximately 8 in
(approximately 20 cm)CornersApproximately 8 in
(approximately 20 cm)
If there is an obstacle within this range, the
relevant warning displays light up and a
warning tone sounds. If the distance falls
below the minimum, the distance may no
longer be shown.
Warning displays
The warning displays show the distance
between the sensors and the obstacle. The
warning display for the front area is in the
instrument cluster. The warning display for
the rear area is located on the headliner in the
rear compartment.
Warning display for the front area
:Segments on the left-hand side of the
vehicle;Segments on the right-hand side of the
vehicle=Segments showing operational readiness
The warning display for each side of the
vehicle is divided into five yellow and two red
segments. PARKTRONIC is operational if
yellow segments showing operational
readiness = light up.
The selected transmission position
determines which warning display is active
when the engine is running.
Transmission
positionWarning displayDFront area activatedRRear and front areas
activatedNIf the electric parking
brake is engaged: no
areas are activated
If the electric parking
brake is released:
rear and front areas
are activatedPNo areas activated
One or more segments light up as the vehicle
approaches an obstacle, depending on the
vehicle's distance from the obstacle.
When the first red segment lights up, you hear
an intermittent warning for about two
seconds. From the second red segment, you
348Driving systemsDriving and parking

Problems with Night View Assist PlusProblemPossible causes/consequences and M SolutionsThe picture quality of
Night View Assist Plus
has deteriorated.The windshield wipers are smearing the windshield.XReplace the wiper blades ( Y page 285).The windshield is smeared after the vehicle has been cleaned in a
car wash.XClean the windshield ( Y page 466).There is windshield chip damage in the camera's field of vision.XReplace the windshield.The windshield is fogged up on the inside.XDefrost the windshield ( Y page 296).The windshield is iced up.XDe-ice the windshield ( Y page 296).There is dirt on the inside of the windshield.XClean the inside of the windshield ( Y page 466).Driving Assistance package
General notes
i The Driving Assistance package is only
available on vehicles with HYBRID.
The Driving Assistance package consists of
DISTRONIC PLUS ( Y page 332), Blind Spot
Assist ( Y page 360) and Lane Keeping Assist
( Y page 362).
Blind Spot Assist
Important safety notes
Blind Spot Assist uses a radar sensor system
to monitor the areas on both sides of your
vehicle. It supports you from speeds of
approximately 20 mph (30 km/h). A warning
display in the exterior mirrors draws your
attention to vehicles detected in the
monitored area. If you then switch on the
corresponding turn signal to change lane, you
will also receive an optical and audible
collision warning. Blind Spot Assist uses
sensors in the rear bumper for monitoring
purposes.GWARNING
Blind Spot Assist is only an aid designed to
assist driving. It may fail to detect some
vehicles and is no substitute for attentive
driving.
Blind Spot Assist cannot detect road and
traffic conditions. It may fail to detect narrow
vehicles, such as motorcycles or bicycles, or
may only detect them too late.
Monitoring may be affected by dirty sensors,
strong spray or poor visibility caused by snow,
rain or mist, for example. In this case, vehicles
are detected late or not at all.
Always pay attention to traffic conditions and
your surroundings. Otherwise, you may fail to
recognize dangers in time, cause an accident
and injure yourself and others.
i USA only:
360Driving systemsDriving and parking

Active Blind Spot Assist (Y page 364) and
Active Lane Keeping Assist ( Y page 367).
Active Blind Spot Assist
Important safety notes
Active Blind Spot Assist uses a radar sensor
system to monitor the side areas of your
vehicle which are in back of the driver. A
warning display in the exterior mirrors draws
your attention to vehicles detected in the
monitored area. If you then switch on the
corresponding turn signal to change lane, you
will also receive an optical and audible
collision warning. If a risk of lateral collision
is detected, corrective braking may help you
avoid a collision. To support the course-
correcting brake application, Active Blind
Spot Assist also uses the forward-facing radar
sensor system. Active Blind Spot Assist
supports you from speeds of approximately
20 mph (30 km/h).
GWARNING
Active Blind Spot Assist is only an aid, and
may detect vehicles/obstacles incorrectly or
not at all.
The system may be impaired or may not
function if:
R there is poor visibility, e.g. due to snow,
rain, fog or spray.
R the rear and/or front sensors are dirty.
Active Blind Spot Assist may not detect
narrow vehicles, such as motorcycles or
bicycles, or may only detect them too late. It
cannot detect vehicles that are overtaken at
a small distance and then enter the blind spot
area.
Active Blind Spot Assist cannot detect road
and traffic conditions. It is not a substitute for
attentive driving. You are responsible for the
vehicle's speed, braking in good time, and
steering correctly. Always adapt your driving
style to suit the prevailing road and weather
conditions. Always pay attention to traffic
conditions and your surroundings. Otherwise,
you may fail to recognize dangers in time,
cause an accident and injure yourself and
others.
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 automotive
radar system only. Removal, tampering, or
altering of the device will void any
warranties, 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.
For Active Blind Spot Assist to assist you
when driving, the radar sensor system must
be activated ( Y page 387) and operational.
Monitoring area
Active Blind Spot Assist monitors the area
shown in the figure up to 10 ft (3 m) behind
and immediately adjacent to your vehicle. For
this purpose, Active Blind Spot Assist uses
radar sensors in the rear bumper.GWARNING
Active Blind Spot Assist monitors certain
areas in the immediate vicinity of your vehicle.
Vehicles that approach and drive past at high
speeds are not detected. No visual nor
364Driving systemsDriving and parking

Display messagesPossible causes/consequences and M SolutionsPRE-SAFE
Functions
Currently Limited
See Operator's
ManualGRisk of accident
PRE-SAFE ®
Brake is temporarily inoperative if:
R the DISTRONIC PLUS cover in the radiator grill is dirty.
R the sensors in the bumpers are dirty.
R its 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
stations or other sources of electromagnetic radiation.
R the system is outside the operating temperature range.
R the on-board voltage is too low.
PRE-SAFE ®
Brake is operational again and the display message
disappears if:
R the dirt (e.g. slush) drops away while the vehicle is in motion.
R the system detects that the sensors are fully available again.
R the system is within the operating temperature range.
If the display message continues to be displayed:
XClean the DISTRONIC PLUS cover in the radiator grill
( Y page 467).XClean the bumpers ( Y page 467).XRestart the engine.XWait until the battery is sufficiently charged.PRE-SAFE
Function Limited
See Oper. ManualGRisk of accident
PRE-SAFE ®
Brake is defective. BAS PLUS or the distance warning
signal may also have failed.
XVisit a qualified specialist workshop.6
SRS Malfunction
Service RequiredGRisk of injury
There is a malfunction in the SRS (Supplemental Restraint
System). The 6 warning lamp also lights up in the instrument
cluster.
XVisit a qualified specialist workshop.Display messages397On-board computer and displaysZ

Display messagesPossible causes/consequences and M SolutionsABC
Vehicle Rising
Please Wait BrieflyThe ABC vehicle level is too low when the vehicle is stationary.XDo not pull away.
The vehicle level is set when the display message disappears.ABC
MalfunctionThe ABC function is restricted. The vehicle's handling
characteristics may be affected.XDo not drive faster than 50 mph (80 km/h).XVisit a qualified specialist workshop.HOLD
OffThe HOLD function is deactivated. The vehicle is skidding.
A warning tone also sounds.XReactivate the HOLD function later ( Y page 342).The HOLD function is deactivated. When the brake pedal is firmly
depressed, an activation condition is not fulfilled.
A warning tone also sounds.XCheck the activation conditions for the HOLD function
( Y page 342).Radar Sensors
Deactivated See
Oper. ManualThe radar sensor system is deactivated.XSwitch on the radar sensor system ( Y page 387).Lane Keeping
Assist Currently
Unavailable. See
Operator's Manual
or Lane Keeping
Assist Currently
Unavailable. See
Operator's ManualLane Keeping Assist or Active Lane Keeping Assist is deactivated
and temporarily inoperative if:
R the windshield 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, for example by dirt
or snow.
Lane Keeping Assist or Active Lane Keeping Assist is operational
again and the display message disappears if:
R the dirt (e.g. slush) drops away while the vehicle is in motion.
R the system recognizes that the camera is fully operational again.
If the display message continues to be displayed:XClean the windshield.Lane Keeping
Assist Inoperative
or Active Lane
Keeping Assist
InoperativeLane Keeping Assist or Active Lane Keeping Assist is defective.XVisit a qualified specialist workshop.Display messages411On-board computer and displaysZ

Display messagesPossible causes/consequences and M SolutionsBlind Spot Assist
Currently
Unavailable See
Oper. Manual or
Active Blind Spot
Assist Currently
Unavailable See
Oper. ManualBlind Spot Assist or Active Blind Spot Assist is temporarily
inoperative if:
R the sensors are dirty.
R its function is impaired due to heavy rain or snow.
R the radar sensor system is outside the operating temperature
range.
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio
stations or other sources of electromagnetic radiation.
The yellow 9 indicator lamps also light up in the exterior
mirrors.
Blind Spot Assist or Active Blind Spot Assist is operational again
and the display message disappears if:
R the dirt (e.g. slush) drops away while the vehicle is in motion.
R the system detects that the sensors are fully available again.
R the radar sensor system is back within the operating
temperature range.
If the display message continues to be displayed:XClean the sensors ( Y page 467).XRestart the engine.Blind Spot Assist
Inoperative or
Active Blind Spot
Assist InoperativeBlind Spot Assist or Active Blind Spot Assist is defective.
The yellow 9 indicator lamps also light up in the exterior
mirrors.XVisit a qualified specialist workshop.Parking Guidance
InoperativeParking Guidance is malfunctioning ( Y page 350).XRestart the engine.
If the display message continues to be displayed:
XVisit a qualified specialist workshop.412Display messagesOn-board computer and displays

Display messagesPossible causes/consequences and M SolutionsDISTRONIC PLUS
Currently
Unavailable See
Operator's ManualDISTRONIC PLUS is deactivated and is temporarily inoperative if:
R the DISTRONIC PLUS cover in the radiator grill is dirty.
R its function is impaired due to heavy rain or snow.
R the sensors in the bumpers are dirty.
R the radar sensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio
stations 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.
DISTRONIC PLUS is operational again and the display message
disappears if:
R the dirt (e.g. slush) drops away while the vehicle is in motion.
R the system detects that the sensors are fully available again.
R the system is within the operating temperature range.
If the display message continues to be displayed:XClean the DISTRONIC PLUS cover in the radiator grill
( Y page 467).XClean the bumpers ( Y page 467).XRestart the engine.DISTRONIC PLUS
InoperativeDISTRONIC PLUS is defective. BAS PLUS (Brake Assist PLUS) and
PRE-SAFE ®
Brake may be inoperative as well.
A warning tone also sounds.XVisit a qualified specialist workshop.DISTRONIC PLUS
OverrideYou have depressed the accelerator pedal. DISTRONIC PLUS is no
longer controlling the speed of the vehicle.XTake your foot off the accelerator pedal.DISTRONIC PLUS
--- mphAn activation condition for DISTRONIC PLUS is not fulfilled.XCheck the activation conditions for DISTRONIC PLUS
( Y page 332).414Display messagesOn-board computer and displays

XSlide the seat backwards.XTo install: place the floormat in the
footwell.XPress studs : onto retainers ;.XTo remove: pull the floormat off
retainers ;.XRemove the floormat.
Infrared reflective windshield
The infrared reflecting glass prevents the
vehicle interior from becoming too hot. It also
blocks radio waves up into the gigahertz
range.
Vehicles without Night View Assist Plus
:Areas permeable to radio waves (to the
left and right of the rain sensor cover);Rain sensor cover=Areas permeable to radio waves
Vehicles with Night View Assist Plus
:Area permeable to radio waves (to the left
of the rain sensor cover);Rain sensor cover=Areas permeable to radio waves
In order to operate radio-controlled
equipment, e.g. toll recording systems,
areas : or = on the windshield are
permeable to radio waves. In these areas, you
can install radio-controlled systems.
These areas can best be seen from outside
the vehicle by observing the light reflected off
the windshield.
454FeaturesStowing and features

Useful information
i This Operator's Manual describes all
models and all standard and optional
equipment of your vehicle available at the
time of publication of the Operator's
Manual. Country-specific differences are
possible. Please note that your vehicle may
not be equipped with all features
described. This also applies to safety-
related systems and functions.
i Please read the information on qualified
specialist workshops ( Y page 31).
Notes on technical data
i The data stated here specifically refers to
a vehicle with standard equipment. Consult
an authorized Mercedes-Benz Center for
the data for all vehicle variants and trim
levels.
Genuine Mercedes-Benz parts
All Mercedes-Benz Centers maintain a supply
of genuine Mercedes-Benz parts for
necessary service and repair work. In
addition, strategically located parts delivery
centers provide for quick and reliable parts
service.
There are more than 300,000 different
genuine Mercedes-Benz parts available for
Mercedes-Benz models.
Genuine Mercedes-Benz parts are subject to
strict quality control. Each part has been
specially developed, manufactured or
selected for Mercedes-Benz vehicles and
fine-tuned for them.
Therefore, only genuine Mercedes-Benz parts
should be used.
GWARNING
Driving safety may be impaired if non-
approved parts, tires and wheels or safety-
relevant accessories are used.
This could lead to malfunctions in safety-
relevant systems, e.g. the brake system. This
could cause you to lose control of your vehicle
and cause an accident.
For this reason, Mercedes-Benz recommends
that you use genuine Mercedes-Benz parts or
parts of equal quality. Only use tires, wheels
and accessories that have been specifically
approved for your vehicle.
! Air bags and Emergency Tensioning
Devices, as well as control units and
sensors for these restraint systems may be
installed in the following areas of your
vehicle:
R doors
R door pillars
R door sills
R seats
R dashboard
R instrument cluster
R center console
Do not install accessories such as audio
systems in these areas. Do not carry out
repairs or welding. You could impair the
operating efficiency of the restraint
systems.
Have aftermarket accessories installed at
a qualified specialist workshop. Mercedes-
Benz recommends that you use an
authorized Mercedes-Benz Center for this
purpose.
HEnvironmental note
Daimler AG also supplies reconditioned major
assemblies and parts which are of the same
quality as new parts. They are covered by the
same Limited Warranty entitlements as new
parts.
Always specify the vehicle identification
number (VIN) ( Y page 521) and the engine
520Genuine Mercedes-Benz partsTechnical data