MERCEDES-BENZ M-Class 2014 W166 Workshop Manual

Occupant Classification System
(OCS)
Method of operation G
WARNING
If the 001A001C indicator lamp illuminates
when an adult or someone larger than a small
individual is in the fron tpassenger seat, have
the fron tpassenger reposition himself or
herself in the seat until the 001A001C
indicator lamp goes out.
In the event of a collision, the air bag control
unit will no tallow front passenger front air bag
deploymen twhen the OCS has classified the
front passenger seat occupant as weighing as
much as or less than a typical 12-month-old
child in a standard child restraint or if the front
passenger seat is classified as being empty.
When the OCS senses that the front
passenger 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 001A001Cindicator lamp will
illuminate when the engine is started and
remain illuminated. This indicates that the
front passenger front air bag is deactivated.
When the OCS senses that the front
passenger seat is classified as being empty,
the 001A001C indicator lamp will illuminate
when the engine is started and remain
illuminated. This indicates that the front
passenger front air bag is deactivated.
When the OCS senses that the front
passenger seat occupant is classified as
being heavier than the weight of a typical 12-
month-old child seated in astandard child
restraint or as being a small individual (such
as a young teenager or asmall adult), the
001A001C indicator lamp will illuminate for
approximately 6seconds when the engine is
started. Depending on occupant weight
sensor readings from the seat, it will then
remain illuminated or go out. With the
001A001C indicator lamp illuminated, the
fron tpassenger fron tair bag is deactivated. With the
001A001C indicator lamp out, the
front passenger front air bag is activated.
When the OCS senses that the front
passenger seat occupant is classified as an
adult or someone larger than a small
individual, the 001A001Cindicator lamp will
illuminate for approximately six seconds
when the engine is started and the ngo out.
This indicates that the front passenger front
air bag is activated.
If the 001A001C indicator lamp is illuminated,
the front passenger front air bag is
deactivated and will not be deployed.
If the 001A001C indicator lamp is not
illuminated, the front passenger front air bag
is activated and will be deployed
R in the event of certain frontal impacts
R if the impact exceeds a predetermined
triggering threshold
R independent of the side impact air bag or
pelvis air bag
If the front passenger front air bag is
deployed, the rate of inflation will be
influenced by
R the rate of vehicle deceleration as assessed
by the air bag control unit
R the front passenger's weight category as
identified by the OCS G
WARNING
According to accident statistics, children are
safer when properly restrained on the rear
seats than on the front-passenger seat. 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
restraint, toddler restraint, or booster seat
recommended for the size and weight of the
child.
The infant or child restraint must be properly
secured with the vehicle's seat belt, the seat
belt and Top Tether strap, or lower anchors Occupant safety
49Safety
Z

and Top Tether strap, fully in accordance with
the child seat manufacturer's instructions.
Occupants, especially children, should always
sit as upright as possible, wear the seat belt
properly and use an appropriately sized infant
restraint, toddler restraint, or booste rseat
recommended for the size and weight of the
child.
Children can be killed or seriously injured by
an inflating air bag. Note the following
important information when circumstances
require you to place a child in the front-
passenger seat:
R Your vehicle is equipped with air bag
technology designed to deactivate the
front-passenger fron tair bag in your vehicle
when the system senses the weight of a
typical 12-month-old child or less along
with the weight of a standard appropriate
child restraint on the front-passenge rseat.
R Ac hild in a rear-facing child restraint on the
front-passenger seat will be seriously
injured or even killed if the front-passenger
front air bag inflates in a collision which
could occur under some circumstances,
even with the air bag technology installed
in your vehicle. The only means to eliminate
this risk completely is never to place a child
in a rear-facing child restraint in the front-
passenger seat. We therefore strongly
recommend that you always place a child
in a rear-facing child restraint on the rear
seat.
R If you install a rear-facing child restraint on
the front-passenger seat, make sure the
001A001C indicator lamp is illuminated,
indicating that the front-passenger front air
bag is deactivated. Should the 001A001C
indicator lamp not illuminate or go out while
the restraint is installed, please check
installation. Periodically check the
001A001C indicator lamp while driving to
make sure that the 001A001Cindicator
lamp is illuminated. If the 001A001C
indicator lamp goes out or remains out, do not transport a child on the front-passenger
seat until the system has been repaired.
Ac
hild in a rear-facing child restraint on the
front-passenger seat will be seriously
injured or even killed if the front-passenger
front air bag inflates.
R If you place a child in a forward-facing child
restraint on the front-passenger seat:
-move the seat as far back as possible
- use the proper child restraint
recommended for the age, size and
weight of the child
- secure child restraint with the vehicle's
seat belt according to the child seat
manufacturer's instructions
R For children larger than the typical 12-
month-old child, the front-passenger front
air bag may or may not be activated. G
WARNING
If the red 001FSRS warning lamp in the
instrument cluster and the 001A001C
indicator lamp light up simultaneously, the
OCS is malfunctioning. The front passenger
front air bag will be deactivated in this case.
Have the system checked by qualified
technicians as soon as possible. Contact an
authorized Mercedes-Ben zCenter.
Only have the seat repaired or replaced at an
authorized Mercedes-Benz Center.
In order to ensure proper operation of the air
bag system and OCS:
R Sit with the seat belt properly fastened in a
position that is as upright as possible with
your back against the seat backrest.
R When seated, a passenger should not
position him/herself in such a way as to
cause the passenger's weight to be lifted
from the seat cushion as this may result in
the OCS being unable to correctly
approximate the passenger's weight
category.
R Read and observe all warnings in this
chapter. 50
Occupant safetySafety

If the key is removed from the ignition lock or
is in position
0, PASSENGER AIRBAG OFF
indicator lamp 0002does not lightu p.
The Occupant Classification System (OCS)
categorizes the occupant on the front-
passenger seat using a weight sensor. The
front-passenger fron tair bag is deactivated
automatically for certain weight categories.
PASSENGER AIRBAG OFF indicator lamp 0002
shows you the current status. If PASSENGER
AIRBAG OFF indicator lamp 0002is lit, the front-
passenger front air bag is disabled.
The system does not deactivate:
R the side impac tair bag
R the window curtain air bag
R the ETDs
To be classified correctly, the front passenger
must sit:
R with the seat belt fastened correctly
R in a position that is as upright as possible
with their back against the seat backrest
R with their feet on the floor
The OCS weight sensor reading is affected if
the occupant's weight is transferred, e.g. by
leaning on the armrest.
If the front-passenger seat, the seat cover or
the seat cushio nare damaged, have the
necessary repair work carried out at a
qualified specialist workshop.
For safety reasons, Mercedes-Benz
recommends that you only use seat
accessories that have been approved by
Mercedes-Benz. Both the drive
rand the front passenger
should always observe the PASSENGER AIR
BAG OFF indicator lamp as an indication of
whethe rornot the front passenger is
positioned correctly. Observe also the air bag
display messages that can be displayed in the
instrument cluster (Y page 293).
If the driver's air bag deploys, this does not
mean that the front-passenger front air bag
will also deploy.
The OCS may have detected that the seat:
R is empty or occupied by the weight of a
typical child up to twelve months old,
seated in a child restraint system.
R is occupied by a small individual, such as a
young teenager or a small adult.
R is occupied by a child in a child restraint
system whose weight is greater than that
of a typical twelve month old child.
These are examples of when the OCS
deactivates the front-passenger front air bag.
Deactivation takes place although the
collision fulfills the criteria for deploying the
driver's air bag.
System self-test G
WARNING
If the 001A001Cindicator lamp does not
illuminate, the system is not functioning. You
must contact an authorized Mercedes-Benz
Center before seating any child on the front
passenger seat. G
WARNING
Objects betwee nthe seat surface and the
child restraint system could affect the
function of the OCS. This could result in the
front-passenger front air bag not functioning
as intended during an accident. This poses an
increased risk of injury or even fatal injury.
Do not place any objectsb etween the seat
surface and the child restraint system. Make
sure that the bottom and back of the child
restraint system make full contact with the
front-passenger seat cushion and backrest. Occupant safety
51Safety
Z

Always comply with the child restraint system
manufacturer's installation instructions.
The PASSENGER AIR BAG OFF indicator lamp
lights up:
R if you turn the SmartKey in the ignition lock
to position 1or 2
R if you press the KEYLESS-GO Start/Stop
button once or twice on vehicles with
KEYLESS-GO
R if an adul tis seated properly on the front-
passenger seat and the OCS classifies the
occupant as an adult
The PASSENGER AIR BAG OFF indicator lamp
goes out againa fter approximately six
seconds.
If the sea tis not occupied and the OCS
detects that the front-passenger seat is
empty, the PASSENGER AIR BAG OFF
indicator lamp will continue to light up. The
PASSENGER AIR BAG OFF indicator lamp will
not go out.
For more information aboutt he OCS, see
"Problems with the Occupant Classification
System" (Y page 53). 52
Occupant safetySafety

Problems with the occupant classification system
G
WARNING
If the 001A001C indicator lamp illuminates and remains illuminated when the weight of a typical
adult or someone larger than a small individual has been detected on the passenger seat, do not
allow any occupant to use the passenger seat until the system has been repaired. G
WARNING
If the 001A001C indicator lamp does not illuminate or remains out with the weight of a typical
12-month-old child in a standard child restraint or less, or is unoccupied, on the front-passenger
seat, do not transport achild on the front-passenger seat until the system has been repaired. Problem Possible causes/consequences and
0001 Solutions
The PASSENGER AIR
BAG OFF indicator
lights up and remains
on.
The person on the
front-passenger seat:
R
has the weight of a
typical adult
R has been determined
by the system not to
be a child The OCS is malfunctioning.
X
Make sure that the front passenger is sitting in a correct, upright
position.
X Have the OCS checked as soon as possible at a qualified
specialist workshop.
X Observe the additional display messages in the multifunction
display (Y page 293). Occupant safety
53Safety Z

Problem Possible causes/consequences and
0001 Solutions
The PASSENGER AIR
BAG OFF indicator
lamp does not light up
and/or stays on.
The front-passenger
seat is:
R
unoccupied
R occupied with the
weight of a child up
to twelve months old
in a child restraint
system The OCS is malfunctioning.
X
Make sure there is nothing between the seat cushion and the
child seat.
X Make sure that the backrest and base of the child restraint
system are resting securely on the front-passenger seat. If
necessary, adjust the position of the front-passenger seat.
X When installing the child restraint system, make sure that the
seat belt is tight. Do not pull the seat belt tight with the front-
passenger seat adjustment .This could result in the seat belt
being pulled too tightly.
X Check the installation of the child restraint system.
X Make sure that no objectsa re applying additional weight onto
the seat.
X If the PASSENGER AIR BAG OFF indicator lamp remains off, have
the OCS system checked as soon as possible at a qualified
specialist workshop .Do not transport a child on the front-
passenger seat until the OCS has been repaired.
X Observe the additional display messages in the multifunction
display (Y page 293). PRE-SAFE
®
(anticipatory occupant
protection system)
Introduction PRE-SAFE
®
takes preemptive measures to
protect occupants in certain hazardous
situations.
Important safety notes !
Make sure that there are no objects in the
footwell or behind the seats when resetting
the seats. There is a risk that the seats
and/or the objects could be damaged.
Despite your vehicle being equipped with the
PRE-SAFE ®
system, the possibility of
personal injuries occurring as a result of an
accident cannot be eliminated.
Always adapt your driving style to suit the
prevailing road and weather conditions and
maintain a safe distance from the vehicle in
front. Drive carefully. Function PRE-SAFE
®
intervenes:
R in emergency braking situations, e.g. when
BAS is activated
R in critical driving situations, e.g. when
physical limits are exceeded and the
vehicle understeers or oversteers severely
R on vehicles with DISTRONIC PLUS: if
BAS PLUS intervenes powerfully or the
radar sensor system detect sanimminent
dange rofcollision in certain situations.
PRE-SAFE ®
takes the following measures
depending on the hazardous situation
detected:
R the front seat belts are pre-tensioned.
R if the vehicle skids, the sliding sunroof and
the side windows are closed so that only a
small gap remains. On vehicles with a
panorama roof with power tilt/sliding
panel, they are closed completely. 54
Occupant safetySafety

R
on vehicles with the memory function:
the front-passenger seat is adjusted if it is
in an unfavorable position.
R vehicles with amulticontour seat: the
airp ressure in the side bolsters of the
backrest is increased.
If the hazardous situation passes without
resulting in an accident, PRE-SAFE ®
slackens
the beltp re-tensioning. On vehicles with
multicontour seats, the air pressure in the
side bolsters is reduced again. All settings
made by PRE-SAFE ®
can then be reversed.
If the seat belts are not released:
X When the vehicle is stationary, move the
backrest or seat back slightly.
The seat beltp re-tensioning is reduced and
the locking mechanism is released.
The seat-belt adjustment is an integral part of
the PRE-SAFE ®
convenience function. More
information about seat-belt adjustment can
be found under "Seat-belt adjustment"
(Y page 57). Seat belts
Important safety notes G
WARNING
The seat belt does not offer the intended level
of protection if the backrest is not in the
upright position. When braking or in the event
of an accident, you could slide underneath the
seat belt and sustain abdomen or neck
injuries, for example. This poses an increased
risk of injury or even fatal injury.
Adjust the seat properly before beginning
yourj ourney. Always make sure that the seat
is in the upright position. G
WARNING
Seat belts cannot protect as intended, if:
R they are damaged, extremely dirty,
bleached or dyed
R the seat belt buckle is damaged or
extremely dirty
R the Emergency Tensioning Devices or the
belt anchorage has been modified.
Damage caused to seat belts in an accident
may not be visible, e.g. by splinters of glass.
Modified or damaged seat belts can tear or
fail, for example in the event of an accident.
Modified Emergency Tensioning Devices may
be deployed unintentionally or fail to be
deployed when required. There is an
increased risk of injury, possibly even fatal.
Never modify seat belts, Emergency
Tensioning Devices, seat belt anchorages and
inertia reels. Ensure that seat belts are not
damaged or worn and are clean.
Only use seat belts that have been approved
for your vehicle by Mercedes-Benz.
The use of seat belts and infant and child
restraint systems is required by law in:
R all 50 states
R the U.S. territories
R the District of Columbia
R all Canadia nprovinces
Even where this is not required by law, all
vehicle occupants should correctly fasten
their seat belts before starting the journey.
i See "Children in the vehicle"
(Y page 60) for further information on
infants and children traveling in the vehicle
as well as on child restraint systems.
Correct use of the seat belts G
WARNING
USE SEAT BELTS PROPERLY
R Seat belts can only work when used
properly.N ever wear seat belts in any other
way than as described in this section, as Occupant safety
55Safety
Z

tha
tcould result in serious injuries in the
event of an accident.
R Each occupant should wear their seat belt
at all times, because seat belts help reduce
the likelihood of and potential severity of
injuries in accidents, including rollovers.
The integrated restraint system includes
SRS (driver front air bag, driver's side knee
bag, front-passenger front air bag, side
impact air bags, window curtain air bags for
the side windows), Emergency Tensioning
Devices, seat belt force limiters, and front
seat knee bolsters.
The system is designed to enhance the
protection offered to properly belted
occupants in certain frontal (front air bags,
driver's side knee bag and ETDs) and side
(side impact air bags, window curtain air
bags, and ETDs) impacts which exceed
preset deployment thresholds and in
certain rollovers (window curtain air bags
and ETDs).
R Never wear the shoulder belt under your
arm, across your neck or off your shoulder.
In a frontal crash, your body would move
too far forward. That would increase the
chance of head and neck injuries. The seat
belt would also apply too much force to the
ribs or abdomen, which could severely
injure internal organs such as your liver or
spleen.
Adjust the seat belt so that the shoulder
section is located as close as possible to
the middle of the shoulder. It should not
touch the neck.N ever pass the shoulder
portion of the seat belt under your arm. For
this purpose, you can adjust the height of
the seat belt outlet.
R Position the lap belt as low as possible on
your hips and not across the abdomen. If
the lap belt is positioned across your
abdomen, it could cause serious injuries in
a crash.
R Never wear seat belts over rigid or
breakable objects in or on your clothing, such as eyeglasses, pens, keys etc., as
these might cause injuries.
R Make sure the seat belt is always fitted
snugly. Take special care of this when
wearing loose clothing.
R Never use a seat belt for more than one
person at a time. Do not fasten a seat belt
around a person and another person or
other objects at the same time.
R Seat belts should not be worn twisted. In a
crash, you would not have the full width of
the seat belt to distribut eimpact forces.
The twisted seat belt against yourb ody
could cause injuries.
R Pregnant women should also always use a
lap-shoulder belt. The lap belt portion
should be positioned as low as possible on
the hips to avoid any possible pressure on
the abdomen.
R Place the seat backrest in a position that is
as upright as possible.
R Check your seat belt during travel to make
sure it is properly positioned.
R Never place your feet on the instrument
panel, dashboard, or on the seat. Always
keep both feet on the floor in front of the
seat.
R When using a seat belt to secure infant
restraints, toddler restraints, or children in
booster seats, always follow the child seat
manufacturer's instructions. G
WARNING
Do not pass seat belts over sharp edges. They
could tear.
Do not allow the seat belt to get caught in the
door or in the seat adjustment mechanism.
This could damage the seat belt.
Never attempt to make modifications to seat
belts. This could impair the effectiveness of
the seat belts. 56
Occupant safetySafety

Fastening seat belts
G
WARNING
According to accident statistics, children are
safer when properly restrained on the rear
seats than on the front-passenger seat .Thus,
we strongly recommend that children be
placed in the rear seat whenever possible.
Regardless of seating position, children 12
years old and under must be seated and
properly secured in an appropriately sized
child restraint system or booster seat
recommended for the size and weight of the
child. For additional information, see the
"Children in the vehicle" section.
Ac hild's risk of serious or fatal injuries is
significantly increased if the child restraints
are not properly secured in the vehicle and/
or the child is not properly secured in the child
restraint. X
Adjust the seat and move the backrest to
an almost vertical position (Y page 104).
X Pull the seat belt smoothly through belt
sash guide 0002.
X Without twisting it, guide the shoulder
section of the seat belt across the middle
of your shoulder and the lap section across
your pelvis. X
Engage belt tongue 0003in buckle 0023.
Seat-belt adjustment:ifn ecessary, the
driver's and front-passenger seat belts
automatically adjust to the upper body
(Y page 57).
X If necessary, adjust the seat belt to the
appropriate height (Y page 58).
X If necessary, pull upwards on the shoulder
section of the seat belt to tighten the belt
across your body.
All seat belts except the driver's seat belt are
equipped with a special seat belt retractor to
securely fasten child restraint systems in the
vehicle. Further information can be found
under "Special seat belt retractor"
(Y page 63).
For more information about releasing the seat
belt with release button 0022, see "Releasing
seat belts" (Y page 58).
Seat belt adjustment The seat-belt adjustment function adjusts the
driver's and front-passenger seat belt to the
upper body of the occupants.
The belt strap is tightened slightly when:
R
you engage the belt tongue in the belt
buckle and you then turn the SmartKey to
position 2in the ignition lock.
R the SmartKey is in position 2in the ignition
lock and you then engage the belt tongue
in the buckle.
The seat-belt adjustment will apply a
retraction force if any slack is detected
between the occupant and the seat belt. Do
not hold on to the seat belt tightly while it is
adjusting. You can switch the seat-belt
adjustment on and off in the on-board
computer (Y page 277).
The seat-belt adjustment is an integral part of
the PRE-SAFE ®
convenience function. More
information about PRE-SAFE ®
can be found
under "PRE-SAFE ®
(preventative occupant
protection)" (Y page 54). Occupant safety
57Safety Z

Belt height adjustment
You can adjus
tthe seat belt height on the
front seats. Adjust the belt to a height that
allows the upper part of the seat belt to be
routed across the center of your shoulder.
X To raise: slide the belt sash guide upwards.
The belt sash guide engages in various
positions.
X To lower: press and hold belt sash guide
release 0002.
X Slide the belt sash guide downwards.
X Release belt sash guide release 0002and
make sure that the belt sash guide has
engaged.
Releasing seat belts !
Make sure that the seat belt is fully rolled
up. Otherwise, the seat belt or belt tongue
will be trapped in the door or in the seat
mechanism. This could damage the door,
the door trim panel and the seat belt.
Damaged seat belts can no longer fulfill
their protective function and must be
replaced. Visit a qualified specialist
workshop. 0002
Belt sash guide
0003 Seat belt tongue
0023 Buckle
0022 Release button
X Press release button 0022and guide belt
tongue 0003back towards belt sash
guide 0002.
Belt warning for the driver and front
passenger Every time the engine is started, the
0020
seat belt warning lamp lights up for six
seconds. It lights up regardless of whether
the driver's and front-passenger seat belts
have already been fastened. If the driver's
and front-passenger seat belts have already
been fastened, the 0020seat belt warning
lamp then goes out.
If the driver's seat belt is not fastened when
the engine is started, an additional warning
tone will sound. This warning tone stops after
a maximum of six seconds or once the
driver's seat belt is fastened.
If after six seconds, the driver or front
passenger have not fastened their seat belts
and the doors are closed:
R the 0020 seat belt warning lamp remains lit
as long as the driver's or front-passenger's
seat belt is not fastened 58
Occupant safetySafety