2008 MERCEDES-BENZ S550 4MATIC sensor

40 Safety and Security
Occupant safety
In this section you will learn the most im-
portant facts about the restraint systems
of the vehicle.
The restraint systems are

Seat belts (page 52)

Child restraints (page 57)

Lower Anchors and Tethers for
CHildren (LATCH) (
page 62)
Additional protection potential provide

Supplemental Restraint System (SRS)
with

Air bags (page 42)

Air bag control unit (with crash
sensors)

Emergency Tensioning Device
(ETD) for seat belts (
page 55)

Seat belt force limiter (page 55)

Preventive occupant safety
(PRE-SAFE®) (page 56)

Active head restraints (page 55)Air bag system components with

The front passenger front air bag off in-
dicator lamp (
page 50)

Front passenger seat with Occupant
Classification System (OCS)
(
page 47)
Although independent systems, their pro-
tective functions work in conjunction with
each other.The SRS system conducts a self-test when
the ignition is switched on and in regular
intervals while the engine is running. This
facilitates early detection of malfunctions.
The =indicator lamp in the instrument
cluster (
page 28) comes on when the
ignition is switched on and goes out no lat-
er than a few seconds after the engine has
been started.
The SRS components are in operational
readiness when the =indicator lamp is
not lit when the engine is running.
A malfunction in the system has been
detected if the =indicator lamp:

fails to go out after approximately
4 seconds after the engine was started

does not come on at all

comes on after the engine was started
or while driving
iFor information on infants and children trav-
eling with you in the vehicle and restraint sys-
tems for infants and children, see “Children in
the vehicle” (
page 57).

47 Safety and Security
Occupant safety
The window curtain air bags fill up the area
indicated by the arrows.
Occupant Classification System
The Occupant Classification System (OCS)
automatically turns the front passenger
front air bag on or off based on the classi-
fied occupant weight category determined
by weight sensor readings from the front
passenger seat.
Occupants must sit properly belted in a po-
sition that is as upright as possible with
their back against the seat backrest and
feet on the floor to be correctly classified.
If the occupant’s weight is transferred to
another object in the vehicle (e.g. by lean-
ing on armrests), the OCS may not be able
to properly approximate the occupant’s
weight category.Furthermore, the occupant weight may ap-
pear to increase or decrease due to
objects hanging on the seat, other passen-
gers pushing on the seat, objects lodged
underneath the seat or stuffed between
seat and middle console or between seat
and door or due to objects applying pres-
sure on the back of the seat. Always make
sure that the seat has clearance in all
directions at all times.
Both driver and the front passenger should
always use the 59indicator
lamp as an indication of whether or not the
front passenger is properly positioned.
iThe system does not deactivate the front
passenger side impact air bag, the window cur-
tain air bag and the emergency tensioning de-
vice.
iIf your seat, including your trim cover and
cushion needs to be serviced in any way, take
the vehicle to an authorized Mercedes-Benz
Center.
Only seat accessories approved by
Mercedes-Benz may be used.
Warning!G
If the 59indicator lamp illumi-
nates when an adult or someone larger than
a small individual is in the front passenger
seat, have the front passenger re-position
himself or herself in the seat until the
59indicator lamp goes out, or
check whether objects are caught under or
around the seat.
More information about air bag display mes-
sages (
page 618).
In the event of a collision, the air bag control
unit will not allow front passenger front air
bag deployment when the OCS classified
the front passenger seat occupant as being
up to or less than the weight of a typical
12-month-old child in a standard child re-
straint or if the front passenger seat is
sensed as being empty.


48 Safety and Security
Occupant safety
When the OCS senses that the front passen-
ger seat occupant is classified as being up
to or less than the weight of a typical
12-month-old child in a standard child
restraint, the 59indicator
lamp will illuminate when the engine is start-
ed and remain illuminated, indicating that
the front passenger front air bag is deacti-
vated.
When the OCS senses that the front passen-
ger seat is classified as being empty, the
59indicator lamp will illumi-
nate when the engine is started and remain
illuminated, indicating that the front
passenger front air bag is deactivated.
When the OCS senses that the front passen-
ger seat occupant is classified as being
heavier than the weight of a typical
12-month-old child seated in a standard
child restraint or as being a small individual
(such as a young teenager or a small adult),
the 59indicator lamp will illu-
minate for approximately 6 seconds when
the engine is started and then, depending on
occupant weight sensor readings fromthe seat, remain illuminated or go out. With
the 59indicator lamp illumi-
nated, the front passenger front air bag is
deactivated. With the 59 indi-
cator lamp out, the front passenger front air
bag is activated.
When the OCS senses that the front passen-
ger seat occupant is classified as an adult or
someone larger than a small individual, the
59indicator lamp will illumi-
nate for approximately 6 seconds when the
engine is started and then go out, indicating
that the front passenger front air bag is
activated.
If the 59indicator lamp is illu-
minated, the front passenger front air bag is
deactivated and will not be deployed.
If the 59indicator lamp is not
illuminated, the front passenger front air
bag is activated and will be deployed:

in the event of certain frontal impacts

if impact exceeds a preset deployment
threshold

independently of the side impact air
bags
If the front passenger air bag is deployed,
the rate of inflation will be influenced by:

the rate of relevant vehicle deceleration
as assessed by the air bag control unit

front passenger’s weight category as
identified by the Occupant Classification
System (OCS).
Warning!G
According to accident statistics, children
are safer when properly restrained in the
rear seating positions than in the front seat-
ing position. Thus, we strongly recommend
that children be placed in the rear seats
whenever possible. Regardless of seating
position, children 12 years old and under
must be seated and properly secured in an
appropriate infant or child restraint
recommended for the size and weight of the
child.


69 Safety and Security
Driving safety systems
BAS Plus*
The Brake Assist System Plus (BAS Plus)
operates in emergency braking situations
and uses radar sensors* to assess the traf-
fic situation. BAS Plus assists you in brak-
ing at speeds above approximately 20 mph
(30 km/h).
When travelling in Canada in a vehicle not
registered in Canada, you must switch off
the radar sensor system* (
page 282).
Canadian law does not permit the use of
the radar sensor system* (
page 282) for
vehicles from outside of Canada. When you
switch off the radar sensor system*, the
following functions are deactivated:

BAS Plus

DISTRONIC Plus* (page 424)

Park Assist* (page 448)

PRE-SAFE® Brake* (page 76)BAS Plus detects obstacles that are in your
driving path for a sufficient period of time
to permit the system to recognize these
obstacles. If you approach the detected
obstacle quickly, BAS Plus calculates the
level of brake power boost appropriate for
the circumstance to supply when the driv-
er applies the brakes.
iUSA 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 de-
vice 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.
iCanada only:
This device complies with RSS-210 of Industry
Canada. Operation is subject to the following
two conditions:
(1) This device may not cause interference, and
(2) this device must accept any interference re-
ceived, 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 in any non-approved
way.
Any unauthorized modification to this device
could void the user’s authority to operate the
equipment.
Warning!G
BAS Plus is a convenience system designed
to assist the driver during vehicle operation.
The responsibility for the vehicle speed and
the distance to the vehicle ahead, including
most importantly brake operation to assure
safe stopping distance, always remains with
the driver.
Always pay attention to traffic conditions
even while BAS Plus is switched on. Other-
wise, you may not be able to recognize
dangerous situations until it is too late and
could cause an accident resulting in person-
al or fatal injury to you or others.

70 Safety and Security
Driving safety systems
When you step quickly on the brake pedal
in an emergency braking situation,
BAS Plus automatically regulates the
brake power boost to a level that is suit-
able for the traffic situation.
If BAS Plus requires a particularly high
brake power boost, PRE-SAFE
® is activat-
ed at the same time.
Keep constant pressure on the brake
pedal until the emergency braking situ-
ation is over.
During this process, ABS prevents the
wheels from locking up.
The brakes will resume normal operation
after

the brake pedal is released

no obstacles are detected in your path

the system no longer senses a risk of a
collision
BAS Plus is deactivated.BAS Plus can react to stationary obstacles
such as standing or parked vehicles at
road speeds of up to approximately
40 mph (70 km/h).
BAS Plus can only assist you when the
radar sensors are switched on and func-
tional. You can check whether the sensors
are active by switching on DISTRONIC
Plus* (
page 424) or using the “Radar
sensor” menu (
page 282) in the instru-
ment cluster control system.
After a hard collision or damage to the
front of the vehicle from an accident, have
the adjustment and operation of the radar
sensors checked by an authorized
Mercedes-Benz Center.
If BAS Plus is not available due to a radar
sensor malfunction, the braking system
will continue to function normally with full
brake boost and full standard BAS
function.
Warning!G
BAS Plus will only respond with brake assis-
tance if it has clearly detected an object. De-
tection can be impeded by

dirty or covered sensors

snowfall or heavy rain

disturbance from other radar sources

strong radar reflection such as in park-
ing garages
BAS Plus uses radar signals that are not re-
flected well by narrow objects and absorp-
tive materials. For this reason BAS Plus will
not react to

persons and animals

approaching traffic or cross-traffic
BAS Plus may not detect narrow vehicles
driving in front of you, such as motorcycles
and vehicles driving offset from your vehicle
center.

77 Safety and Security
Driving safety systems
PRE-SAFE® Brake will only assist you by
automatically initiating braking if the driver
and front passenger have their seat belts
fastened.
Using the radar sensors, PRE-SAFE
® Brake
detects obstacles that are in your driving
path for a sufficient period of time for the
system to recognize it. If you approach a
vehicle and PRE-SAFE
® Brake has estab-
lished that the distance to the vehicle
ahead at your current speed is so close
that PRE-SAFE
® Brake will not be capable
of slowing the vehicle sufficiently, the sys-
tem will initially warn you visually and
acoustically.When travelling in Canada in a vehicle not
registered in Canada, you must switch off
the radar sensor system* (
page 282).
Canadian law does not permit the use of
the radar sensor system* (
page 282) for
vehicles from outside of Canada. When you
switch off the radar sensor system*, the
following functions are deactivated:

BAS Plus* (page 69)

DISTRONIC Plus* (page 424)

Park Assist* (page 448)

PRE-SAFE® Brake
Always pay attention to traffic conditions
even while PRE-SAFE® Brake is switched on.
Otherwise, you may not be able to recognize
dangerous situations until it is too late and
could cause an accident resulting in person-
al or fatal injury to you or others.
iUSA 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 de-
vice 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.
iCanada only:
This device complies with RSS-210 of Industry
Canada. Operation is subject to the following
two conditions:
(1) This device may not cause interference, and
(2) this device must accept any interference re-
ceived, 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 in any non-approved
way.
Any unauthorized modification to this device
could void the user’s authority to operate the
equipment.

78 Safety and Security
Driving safety systems
When the distance to the forward vehicle is
too small, the distance warning lampl
lights up in the instrument cluster. If you
approach the forward vehicle very quickly,
you will hear a warning tone.
If you do not apply the brakes yourself or
maneuver around a sensed obstacle, the
vehicle will automatically initiate light
braking. PRE-SAFE
® (page 56) is activat-
ed when the distance to the vehicle ahead
at your current speed is so close that
PRE-SAFE
® Brake will not be capable of
slowing the vehicle sufficiently.
Warning!G
PRE-SAFE® Brake will only respond with
brake assistance if it has clearly detected an
object. Detection can be impeded by

dirty or covered sensors

snowfall or heavy rain

disturbance from other radar sources

strong radar reflection such as in park-
ing garages
PRE-SAFE
® Brake uses radar signals that
are not reflected well by narrow objects and
absorptive materials. For this reason BAS
Plus will not react to

persons and animals

approaching traffic or cross-traffic
PRE-SAFE
® Brake may not detect narrow ve-
hicles driving in front of you, such as motor-
cycles and vehicles driving offset from your
vehicle center.
Warning!G
PRE-SAFE® Brake brakes your vehicle with a
maximum of 13 ft/s2 (4 m/s2). This corre-
sponds to about 40% of the maximum decel-
eration ability of your vehicle. This
automatic braking is intended only to ini-
tiate the braking if the driver has not already
done so. The driver must apply the brakes in
order to prevent a collision.
PRE-SAFE
® Brake applies the brake pedal
automatically which results in the brake
pedal moving. Therefore keep driver’s foot
area clear at all times, including the area un-
der the brake pedal. Objects stored in this
area may impair pedal movement which
could interfere with the braking ability of the
PRE-SAFE
® Brake.
Do not place your foot under the brake pedal
– your foot could become caught.

80 Safety and Security
Driving safety systems
PRE-SAFE® Brake does not always clearly
interpret complex traffic situations. If a vi-
sual and/or acoustic warning is issued in
an uncritical driving situation, or if the ve-
hicle brakes lightly, you can interrupt the
PRE-SAFE
® Brake maneuver by

pressing down all the way on the accel-
erator or using kickdown

releasing the brake pedalThe PRE-SAFE
® Brake maneuver is termi-
nated immediately when

you avoid the obstacle by evasive
steering

you drive less than 9 mph (15 km/h)

an obstacle can no longer be identified
ahead of you

the system no longer senses the risk of
a collisionAfter a hard collision or damage to the
front of the vehicle from an accident, have
the settings and operation of the radar
sensors checked by an authorized
Mercedes-Benz Center.
iPRE-SAFE® Brake will remain passive while
DISTRONIC Plus* is switched on (
page 424).