Sensor MERCEDES-BENZ S-Class 2012 W221 Owner's Guide

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 Blind Spot Assist to assist you when
driving, the radar sensor system must be
activated ( Y page 387) and operational.
Monitoring range of the sensors
Blind Spot Assist monitors the area shown in
the figure up to 10 ft (3 m) behind and
immediately adjacent to your vehicle.GWARNING
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. There is no display and no
warning.
If the lanes are very wide, it may not be
possible to monitor the complete width of the
neighboring lane. For this reason, vehicles in
the next lane may not be detected, especially
if they are driving in a staggered formation.
This may be the case if vehicles are driving at
that edge of their lane which is furthest away
from your vehicle.
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.
If the lanes are narrow, vehicles driving in the
lane beyond the lane next to your vehicle may
be indicated, especially if the vehicles are not
driving in the middle of their lane. This may
be the case if the vehicles are driving on the
inner side of their lane.
Due to the nature of the system:
R warnings may be issued in error when
driving close to crash barriers or similar
solid lane borders.
R warnings may be interrupted when driving
alongside long vehicles, such as trucks, for
a prolonged time.
The two sensors for Blind Spot Assist are
integrated into the sides of the rear bumper.
Make sure that the bumper is free from dirt,
ice or slush around the sensors. The rear
sensors must not be covered, for example by
bicycle racks or overhanging loads. Following
a severe impact or in the event of damage to
the bumpers, have the function of the radar
sensors checked at a qualified specialist
workshop, e.g. an authorized Mercedes-Benz
Center. Blind Spot Assist may otherwise not
work properly.
Indicator and warning display:Yellow indicator lamp/red warning lampDriving systems361Driving and parkingZ

When Blind Spot Assist is activated, indicator
lamp : lights up yellow in the exterior
mirrors up to a vehicle speed of 20 mph
(30 km/h). When the vehicle speed exceeds
20 mph (30 km/h), the indicator lamp goes
out and Blind Spot Assist is ready for use.
When your speed exceeds approximately
20 mph (30 km/h), warning lamp : lights up
red on the corresponding side whenever a
vehicle is detected in the blind spot
monitoring range. This warning is always
given when a vehicle enters the blind spot
monitoring range from behind or from the
side. When you are passing another vehicle,
the warning is emitted only if the difference
in speed is less than 7 mph (12 km/h).
The yellow indicator lamp goes out if reverse
gear is engaged. In this event, Blind Spot
Assist is no longer active.
The brightness of the indicator/warning
lamps is adjusted automatically according to
the ambient light.GWARNING
Blind Spot Assist is not active at speeds under
approximately 20 mph (30 km/h). The
indicator lamps in the exterior mirrors are
yellow. Vehicles in the monitoring range are
then not indicated.
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.
Collision warning
If a vehicle is detected in the monitoring range
of Blind Spot Assist and you switch on the turn
signal, a double warning tone sounds. Red
warning lamp : flashes. If the turn signal
remains on, detected vehicles are indicated
by the flashing of red warning lamp :. There
are no further warning tones.
Switching on Blind Spot Assist
XMake sure that the radar sensor system
( Y page 387) and Blind Spot Assist(Y page 385) are activated in the on-board
computer.XTurn the SmartKey to position 2 in the
ignition lock.
Warning lamps : light up red in the
exterior mirrors for approximately 1.5
seconds and then turn yellow.
Lane Keeping Assist
Important safety notes
Lane Keeping Assist monitors the area in
front of your vehicle by means of a camera at
the top of the windshield. Lane Keeping Assist
detects lane markings on the road and warns
you before you leave your lane
unintentionally.
:Lane Keeping Assist camera
If you have chosen the Display Unit
Speed-/Odometer (Y page 386) function in
the on-board computer and select km as the
unit of measurement, Active Lane Keeping
Assist is active from speeds of 60 km/h. If
the mph display unit is selected, the
assistance range begins at 40 mph.
GWARNING
Lane Keeping Assist does not keep your
vehicle in its lane. It is only an aid and may
detect the lane markings on the road
incorrectly or not at all.
362Driving 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

audible warnings are emitted and the system
does not brake the vehicle to correct your
course.
If the lanes are very wide, it may not be
possible to monitor the complete width of the
neighboring lane. For this reason, vehicles in
the next lane may not be detected, especially
if they are driving in a staggered formation.
This may be the case if vehicles are driving at
that edge of their lane which is furthest away
from your vehicle.
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.
If the lanes are narrow, vehicles driving in the
lane beyond the lane next to your vehicle may
be indicated, especially if the vehicles are not
driving in the middle of their lane. This may
be the case if there are vehicles driving at the
inner edge of their lanes.
Due to the nature of the system:
R warnings may be issued in error when
driving close to crash barriers or similar
solid lane borders.
R warnings may be interrupted when driving
alongside long vehicles, such as trucks, for
a prolonged time.
Two Active Blind Spot Assist radar sensors
are integrated into the front and rear bumpers
respectively. An additional radar sensor is
located behind the cover in the radiator grill.
Make sure that the sensor areas on the
bumpers and the sensor cover in the radiator
grill are free of dirt, ice and slush. The rear
sensors must not be covered, for example by
cycle racks or overhanging cargo. Following
a severe impact or in the event of damage to
the bumpers, have the function of the radar
sensors checked at a qualified specialist
workshop. Blind Spot Assist may otherwise
not work properly.Indicator and warning display:Yellow indicator lamp/red warning lamp
When Active Blind Spot Assist is activated,
indicator lamp : lights up yellow in the
exterior mirrors up to a vehicle speed of
20 mph (30 km/h). When the vehicle speed
exceeds 20 mph (30 km/h), the indicator
lamp goes out and Active Blind Spot Assist is
ready for use.
When your speed exceeds approximately
20 mph (30 km/h), warning lamp : lights up
red on the corresponding side whenever a
vehicle is detected in the blind spot
monitoring range. This warning is always
given when a vehicle enters the blind spot
monitoring range from behind or from the
side. When you are passing another vehicle,
the warning is emitted only if the difference
in speed is less than 7 mph (12 km/h).
The yellow indicator lamp goes out if reverse
gear is engaged. In this event, Active Blind
Spot Assist is no longer active.
The brightness of the indicator/warning
lamps is adjusted automatically according to
the ambient light.
GWARNING
Active Blind Spot Assist is not active at speeds
lower than 20 mph (30 km/h). The indicator
lamps in the exterior mirrors are yellow.
Vehicles in the monitoring range are then not
indicated.
Always pay attention to traffic conditions and
your surroundings. Otherwise, you may fail to
Driving systems365Driving and parkingZ

recognize dangers in time, cause an accident
and injure yourself and others.
Visual and audible collision warnings
If you switch on the appropriate turn signals
and a vehicle is detected in the side
monitoring range, you will receive a visual and
acoustic collision warning. You will hear a
double warning tone and red warning
lamp : flashes. If the turn signal remains on,
vehicles detected are indicated by the
flashing of red warning lamp :. There are no
further warning tones.
Course-correcting brake application
If Active Blind Spot Assist detects a risk of a
lateral collision in the monitoring range, a
course-correcting brake application is carried
out. This is meant to assist you in avoiding a
collision.
The course-correcting brake application is
available in the range between 20 mph
(30 km/h) and 120 mph (200 km/h).
If a course-correcting brake application
occurs, red warning lamp : flashes in the
exterior mirror and the following is shown in
the multifunction display, for example:GWARNING
Active Blind Spot Assist is only an aid
designed to assist driving. It is not a substitute
for attentive driving. In some cases, the
course-correcting brake application is not
sufficient to avoid a collision. In such a case,
you must steer, brake or accelerate.
In very rare cases, the system may
erroneously detect a danger of collision in the
area of crash barriers or similar lane borders
and apply the brakes. Active Blind Spot Assist
does not detect all traffic situations and road
users. Always make sure that there is
sufficient distance on the side for other traffic
or obstacles. An inappropriate brake
application may be interrupted at any time if
you steer slightly in the opposite direction or
accelerate.
You are responsible for driving at appropriate
speeds, 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.
There will be either no or only a weak course-
correcting brake application if:
R there are vehicles or obstacles, e.g. crash
barriers, located on both sides of your
vehicle.
R a vehicle approaches you too closely at the
side.
R you have adopted a sporty driving style with
high cornering speeds.
R you clearly brake or accelerate.
R a driving safety system intervenes, e.g.
ESP ®
or PRE-SAFE ®
Brake.
R ESP ®
is switched off.
R a loss of tire pressure or a defective tire is
detected.
Switching on Active Blind Spot AssistXMake sure that the radar sensor system
( Y page 387) and Active Blind Spot Assist
( Y page 385) are activated in the on-board
computer.XTurn the SmartKey to position 2 in the
ignition lock.
Warning lamps : light up red in the
exterior mirrors for approximately 1.5
seconds and then turn yellow.366Driving systemsDriving and parking

XPress a.
The current selection is displayed.XTo activate/deactivate: press a
again.
When ATTENTION ASSIST ( Y page 356) is
activated, the À symbol appears in the
multifunction display when the ignition is on.
Activating/deactivating Blind Spot
Assist
You can use the Blind Spot Assist
function to activate or deactivate Blind Spot
Assist ( Y page 360) or Active Blind Spot
Assist ( Y page 364).
XPress = or ; on the steering wheel
to select the DriveAssist menu.XPress 9 or : to select Blind Spot
Assist .XPress a.
The current selection is displayed.XTo activate/deactivate: press a
again.
Activating/deactivating Lane Keeping
Assist
You can use the Lane Keeping Assist
function to activate/deactivate Lane Keeping
Assist ( Y page 362) or Active Lane Keeping
Assist ( Y page 367).
XPress the = or ; button on the
steering wheel to select the DriveAssist
menu.XPress the 9 or : button to select
Lane Keeping Assist .XPress a.
The current selection is displayed.XTo activate/deactivate: press a
again.
If Lane Keeping Assist or Active Lane keeping
Assist is activated, the multifunction display
shows the à symbol when the ignition is
switched on.
Service menu
In the Service menu you can:
R call up display messages ( Y page 388)
R check the tire pressure electronically
( Y page 497)
R call up the service due date ( Y page 462)
R check the oil level ( Y page 457)
Settings menu
Introduction
The Settings menu can be used for:
R switching the daytime running lamps on/
off
R switching Adaptive Highbeam Assist on/
off
R showing or hiding the additional
speedometer
R selecting the units for speed and distance
R switching the belt adjustment on/off
R activating/deactivating the radar sensor
system
Switching the daytime running lamps
on/off
This function is not available in Canada.
If you have activated the Daytime Running
Light function and the light switch is in the
$ or c position, the daytime running
lamps are switched on automatically when
the engine is running.
In the dark, the following also light up:
R the parking lamps
R the tail lamps
R the license plate lamp
R the side marker lamps
If you turn the light switch to a different
position, the corresponding lights are
switched on. If you switch off the daytime
running lamps at night, make sure that the
light switch is set to L or c .
The factory setting is On.
Menus and submenus385On-board computer and displaysZ

XPress the = or ; button on the
steering wheel to select the Settings
menu.XPress the 9 or : button to select
Acoustic Lock Feedb.XPress the a button to confirm.XTo activate/deactivate: press a
again.
Activating/deactivating the radar
sensor system
The following systems are switched off when
the radar sensor system is deactivated:
R DISTRONIC PLUS ( Y page 332)
R BAS PLUS ( Y page 70)
R PRE-SAFE ®
Brake ( Y page 73)
R Blind Spot Assist ( Y page 360)
R Active Blind Spot Assist ( Y page 364)
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.
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
interference, and
2. this device must accept any interference
received, including interference that may
cause undesired operation.
Any unauthorized modification to this
device could void the user's authority to
operate the equipment.
XPress the = or ; button on the
steering wheel to select the Settings
menu.XPress 9 or : to select Radar
sensors .XPress the a button to confirm.XTo activate/deactivate: press a
again.Menus and submenus387On-board computer and displaysZ

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 Solutionsb
Check Left Reverse
Lamp or Check Right
Reverse LampThe left or right-hand backup lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 282).
or
XVisit a qualified specialist workshop.b
Check Front Left
Sidemarker
Lamp or Check Front
Right Sidemarker
LampThe left or right front side marker lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 282).
or
XVisit a qualified specialist workshop.b
Check Rear Left
Sidemarker
Lamp or Check Rear
Right Sidemarker
LampThe rear left or right side marker lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 282).
or
XVisit a qualified specialist workshop.b
Check Left Daytime
Running
Light or Check
Right Daytime
Running Light The left or right-hand daytime running lamp is defective.XCheck whether you are permitted to change the bulb yourself
( Y page 282).
or
XVisit a qualified specialist workshop.b
Active Headlamps
InoperativeThe active light function is defective.XVisit a qualified specialist workshop.b
Malfunction See
Oper. ManualThe exterior lighting is defective.XVisit a qualified specialist workshop.b
AUTO Lamp Function
InoperativeThe light sensor is defective.XVisit a qualified specialist workshop.
USA only:
XSwitch off the daytime running lamps in the on-board computer
( Y page 385).XSwitch the lights on and off using the light switch.Display messages403On-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