2014 MERCEDES-BENZ M-Class light

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

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

and
R if a vehicle speed of 15 mph (25 km/h) is
exceeded, the 0020seat belt warning lamp
begins to flash. Awarning tone also sounds
with increasing intensity for a maximum of
60 seconds or until the driver or front
passenger have fastened their seat belts.
If the driver/front passenger unfasten their
seat belt while the vehicle is in motion, the
0020 seat belt warning lamp lights up and a
warning tone sounds again.
The warning tone ceases eve nifthe driver or
front-passenger seat belt has still not been
fastened after 60 seconds. The 0020seat belt
warning lamp stops flashing but remains
illuminated.
After the vehicle comes to a standstill, the
warning tone is reactivated. The 0020seat
belt warning lamp flashes again if the vehicle
speed exceeds 15 mph (25 km/h).
The 0020 seat belt warning lamp only goes
out if:
R both the driver and the front passenger
have fastened their seat belts.
or
R the vehicle is stationary and a door is open.
i For more information on the 0020seat
belt warning lamp, see "Warning and
indicator lamps in the instrument cluster,
seat belts" (Y page 317).
Emergency Tensioning Devices, seat
belt force limiters G
WARNING
Pyrotechnic Emergency Tensioning Devices
that have been deployed are no longer
operational and are unable to perform their
intended protective function. This poses an
increased risk of injury or even fatal injury.
Therefore, have pyrotechnic Emergency
Tensioning Devices which have been
triggered immediately replaced at a qualified
specialist workshop. !
If the front-passenger seat is not
occupied, do not engage the seat belt
tongue in the buckle on the front-
passenger seat. Otherwise, the Emergency
Tensioning Device could be triggered in the
event of an accident.
i Vehicles with PRE-SAFE ®
: Emergency
Tensioning Devices that are triggered by an
electric motor can be deployed as often as
desired and do not need to be replaced.
The front seat belts and the outer seat belts
in the rear are equipped with Emergency
Tensioning Devices and seat belt force
limiters.
The Emergency Tensioning Devices on the
driver's and front-passenger seat consist of
pyrotechnic belt buckle tensioners and belt
anchor installation tensioners that are
triggered together. The belt buckle tensioner
is mounted on the B-pillar and the belt anchor
installation is mounted on the side of the seat.
After deploying, both tensioners must always
be replaced.
Emergency Tensioning Devices tighten the
seat belts in an accident, pulling them close
against the body.
Emergency Tensioning Devices do not
correct incorrect seat positions or incorrectly
fastened seat belts.
Emergency Tensioning Devices do not pull
vehicle occupants back towards the
backrest.
When triggered, seat belt force limiters help
to reduce the force exerted by the seat belt
on the vehicle occupant.
The seat belt force limiters for the front seats
are synchronized with the front air bags,
which take on a part of the deceleration force.
This results in the force exerted on the
occupant being distributed over a greater
area. Occupant safety
59Safety Z

Emergency Tensioning Devices can only be
activated when:
R
the ignition is switched on.
R the restraint systems ar eoperational; see
"SRS warning lamp" (Y page 43)
R the belt tongue is engaged in the buckle on
each of the lap-shoulder belts in the front
R the front-passenger seat is occupied and
the belt tongue is engaged in the buckle on
the front-passenger side
The ETDs on the outside seats in the rear
compartment are triggered independently of
the lock status of the seat belts.
The ETDs are triggered depending on the type
and severity of an accident:
R if, in the event of a head-on or rear-end
collision, the vehicle decelerates or
accelerates rapidly in a longitudinal
direction during the initial stages of the
impact.
R if, in the event of a side impact, on the side
opposite the impact the vehicle
decelerates or accelerates rapidly in a
lateral direction.
R if, in certain situation swhere the vehicle
rolls over, the system determines that it
can provide additional protection.
If the ETDs are deployed, you will hear a bang,
and a small amount of powder may also be
released. Only in rare cases will the bang
affect your hearing. The powder that is
released generally does not constitute a
health hazard and does not indicate that there
is a fire in the vehicle. The dust might cause
some temporary breathing difficulty for
people with asthma or other breathing
trouble. To avoid this, you may wish to get out
of the vehicle as soon as it is safe to do so.
You can also open the window to allow fresh
air to enter the vehicle interior. The 001FSRS
warning lamp lights up. Children in the vehicle
Child restraint systems
Important safety notes G
WARNING
According to accident statistics, children are
safer when properly restrained in the rear
seating positions than in the front seating
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 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 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 booster seat
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 front air 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 passenger seat.
R For children larger than the typical
12-month-old child, the front passenger
front air bag may or may not be activated.
Always make sure the 001A001Cindicator
lamp is illuminated, indicating that the front
passenger front air bag is deactivated. 60
Children in the vehicleSafety

G
WARNING
Infants and small children should never share
a seat beltw ith another occupant .Inthe event
of an accident, they could be crushed
between the occupant and seat belt.
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.
Children that are too large for a child restraint
must travel in seats using normal seat belts.
Position the shoulder belt across the chest
and shoulder, not face or neck.Ab ooster seat
may be necessary to achieve proper seat belt
positioning for children over 41 lb (18 kg) until
they reach a height where a lap-shoulder belt
fits properly without a booster.
When the child restraint is not in use, remove
it from the vehicle or secure it with the seat
belt to prevent the child restraint from
becoming a projectile in the event of an
accident. G
WARNING
If children are left unsupervised in the vehicle,
they could:
R open the doors, thus endangering other
people or road users.
R get out and disrupt traffic.
R operate the vehicle's equipment.
Additionally, children could set the vehicle in
motion if, for example, they:
R release the parking brake.
R shifting the automatic transmission out of
park position P
R Start the engine.
There is a risk of an accident and injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children or animals unattended in the
vehicle. Always keep the SmartKey out of
reach of children. G
WARNING
If persons, particularly children are subjected
to prolonged exposure to extreme heat or
cold, there is a risk of injury, possibly even
fatal. Never leave children unattended in the
vehicle. G
WARNING
If the child restraint system is subjected to
direct sunlight, parts may get very hot.
Children may burn themselves on these parts,
particularly on the metal parts of the child
restraint system. There is a risk of injury.
If you leave the vehicle, taking the child with
you, always ensure that the child restraint
system is not exposed to direct sunlight.
Protect it with a blanket, for example. If the
child restraint system has been exposed to
direct sunlight, let it cool down before
securing the child in it. Never leave children
unattended in the vehicle.
If an infant or child is traveling in the vehicle:
R secure the child with a child or infant seat
restraint system appropriate to the age and
weight of the child.
R make sure that the infant or child is
properly secured at all times while the
vehicle is in motion.
Mercedes-Benz recommends that you always
properly secure all infant sand children with
a child or infant seat restraint system for the
trip.
The use of sea tbelts and infan tand 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
Infants and children must always be seated in
an appropriate infant or child restraint system
recommended for the size and weight of the
child .The infant or child restraint system
must be properly secured in accordance with
the manufacturer's instructions. 62
Children in the vehicleSafety

X
Route Top Tether belt 0021under head
restraint 0023between the two head restraint
bars.
X Guide Top Tether belt 0021downwards
between cargo compartmen tcover 0002and
rear seat backrest 0003.
X Hook Top Tether hook 0020of Top Tether belt
0021 into Top Tether anchorage 0022.
Make sure that:
R Top Tether hook 0020is hooked into Top
Tether anchorage 0022as shown.
R Top Tether belt 0021is not twisted.
R Top Tether belt 0021is routed between rear
seat backrest 0003and cargo
compartment cover 0002if cargo
compartment cover 0002is installed.
R Top Tether belt 0021is routed between the
rear seat backrest 0003and the cargo net
if the cargo net is installed.
X Tension Top Tether belt 0021.Comply with
the manufacturer's installation
instructions when doing so.
X Move head restraint 0023back down again
slightly if necessary (Y page 108). Make
sure that you do not interfere with the
correc trouting of Top Tether belt 0021.Child-proof locks
Important safety notes G
WARNING
If children are left unsupervised in the vehicle,
they could:
R open the doors, thus endangering other
people or road users.
R get out and disrupt traffic.
R operate the vehicle's equipment. Additionally, children could set the vehicle in
motion if, for example, they:
R
release the parking brake.
R shifting the automatic transmission out of
park position P
R Start the engine.
There is a risk of an accident and injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children or animals unattended in the
vehicle. Always keep the SmartKey out of
reach of children. G
WARNING
If persons, particularly children are subjected
to prolonged exposure to extreme heat or
cold, there is a risk of injury, possibly even
fatal. Never leave children unattended in the
vehicle. G
WARNING
If children are traveling in the vehicle, they
could:
R open doors, thus endangering other people
or road users
R exit the vehicle and be caught by oncoming
traffic
R operate vehicle equipment and become
trapped
There is a risk of an accident and injury.
Always activate the child-proof locks and
override feature if children are traveling in the
vehicle. When leaving the vehicle, always take
the key with you and lock the vehicle. Never
leave children unattended in the vehicle.
You can activate the following child-proof
locks:
R rear doors (Y page 66)
R rear side windows (Y page 66) Children in the vehicle
65Safety Z