2012 MERCEDES-BENZ GL-Class Owner's Manual

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
42 indicator lamp is
illuminated, indicating that the front-
passenger front air bag is deactivated.
Should the 42 indicator lamp
not illuminate or go out while the restraint
is installed, please check installation.
Periodically check the 42
indicator lamp while driving to make sure
the 42 indicator lamp is
illuminated. If the 42 indicator
lamp goes out or remains out, do not
transport a child on the front-passenger
seat until the system has been repaired.
A child 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 a typical 12-month-
old child, the front-passenger front air bag
can be activated or deactivated.
If the driver's air bag deploys, this does not
mean that the front-passenger front air bag
also has to deploy.
The OCS may have detected that the seat:
R was empty or occupied by a person with a
weight of up to or less than that of a typical12-month-old child seated in a standard
child restraint
R was occupied by a small individual, such as
a young teenager or a small adult
R was occupied by a child in a child restraint
system, whose weight is greater than that
of a typical 12-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.
If the SmartKey has been removed from the
ignition lock or is in position 0, indicator lamp
42 : does not light up.
GWARNING
If the red + SRS warning lamp in the
instrument cluster and the 42
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-Benz Center.
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 Do not place more than 4.4 lb (2 kg) into the
parcel net on the rear of the front
passenger seat. Otherwise, the OCS may
Occupant safety47SafetyZ

not be able to properly approximate the
occupant weight category.
R Do not place objects under and/or around
the front passenger seat.
R Do not hang anything from or attach any
items to the seats.
R do not store any objects, such as books,
between the front passenger seat and the
center console or the front-passenger door.
R Do not move the front passenger seat
backwards against rigid objects.
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.
System self-test
The 42 indicator lamp
illuminates when you:
R turn the SmartKey to position 1 or 2 in the
ignition lock
R press the KEYLESS-GO Start/Stop button
once or twice
If an adult occupant is properly sitting on the
passenger seat and the OCS classifies the
occupant as an adult, the 42
indicator lamp illuminates and goes out again
after approximately 6 seconds.
If the seat is not occupied and the OCS
classifies the front passenger seat as being
unoccupied, the 42 indicator
lamp will illuminate and not go out.
GWARNING
If the 4 2 indicator 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.
For more information, see "Problems with the
Occupant Classification System"
( Y page 49).GWARNING
Never place anything between seat cushion
and child seat (e.g. a pillow), since it reduces
the effectiveness of the OCS. The underside
and rear side child restraint system must be
placed entirely on the seat cushion and the
backrest of the front-passenger seat
backrest.
If necessary, adjust the tilt of the passenger
seat backrest.
An incorrectly mounted child seat could cause
injuries to the child in case of an accident,
instead of increasing protection for the child.
Follow the manufacturer's instructions for
installation of child restraint systems.
48Occupant safetySafety

Problems with the occupant classification systemProblemPossible causes/consequences and M SolutionsThe 42
indicator lamp
illuminates and
remains illuminated.
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.XHave the OCS checked as soon as possible at an authorized
Mercedes-Benz Center.XObserve the additional display messages in the multifunction
display ( Y page 239).GWARNING
If the 42 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,
the system then determines the occupant cannot be a child. Do not allow any occupant to use
the passenger seat until the system has been repaired.
ProblemPossible causes/consequences and M SolutionsThe 42
indicator lamp does not
illuminate and/or does
not remain illuminated.
The front-passenger
seat is:
R unoccupied
R occupied with a
weight up to or less
than a typical 12-
month-old child in a
standard child
restraint systemThe OCS is malfunctioning.XMake sure there is nothing between the seat cushion and the
child seat.XCheck the installation of the child restraint system.XMake sure that no objects are applying additional weight onto
the seat.XMake sure there are no objects applying additional force to the
seat. Head restraints that press against the roof or books that
are behind or trapped between the seat, for example, apply
additional force to the seat. The OCS senses such forces as
additional weight.XIf the 42 indicator lamp does not illuminate, have
the OCS checked as soon as possible at an authorized
Mercedes-Benz Center. Do not transport a child on the front-
passenger seat as long as the OCS is not functioning.XObserve the additional display messages in the multifunction
display ( Y page 239).Occupant safety49SafetyZ

GWARNING
If the 42 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 a child on the front-passenger seat until the system has been
repaired.
BabySmart™ air bag deactivation
system
How the air bag deactivation system
works
The BabySmart™ system is standard
equipment in Canada.
GWARNING
Accident statistics show that children
secured in the rear seats are safer than
children secured in the front-passenger seat.
For this reason, Mercedes-Benz strongly
advises that you always secure children in the
rear seats. Regardless of the seat position,
children under 12 years must be secured
correctly in a suitable infant or child restraint
system or booster seat suitable for the size
and weight of the child.
Secure the infant restraint system or child
restraint system using:
R the seat belt of the vehicle
R the seat belt and a Top Tether belt
R the LATCH-type (ISOFIX) child seat mount
and a Top Tether belt
The child restraint system must be installed
and secured correctly, observing the
manufacturer's installation instructions.
Occupants, in particular children, must sit as
upright as possible, fasten the seat belt
correctly and use a suitable infant restraint
system, child restraint system or booster seat
suitable for the size and weight of the child.
Children can be seriously or even fatally
injured by an air bag deploying. Observe the
following important information if it is
necessary to carry a child on the front-
passenger seat:
R Canada only: children under 12 years of age
may only sit in the front-passenger seat if
they are seated in a child restraint system
which is compatible with BabySmart™ and
approved by Mercedes-Benz. When the
child restraint system is installed correctly,
the front-passenger front air bag is disabled
in conjunction with the BabySmart™
system installed in the vehicle. If the front-
passenger front air bag is deployed in the
event of a collision, it could hit the child.
This could lead to serious or fatal injuries.
R A child in a rearward-facing child restraint
system on the front-passenger seat could
be seriously injured or even killed if the
front-passenger front air bag inflates in a
collision despite the air bag technology
installed in your vehicle, which could occur
under some circumstances. The only way
to completely rule out this risk is by making
sure you never place a child in a rearward-
facing child restraint system on the front-
passenger seat. For this reason, we
strongly advise that you always carry
children in a rearward-facing child restraint
system on a rear seat.
R If it is necessary to install a BabySmart™-
compatible rear-facing child restraint
system on the front-passenger seat, make
sure the 42 indicator lamp is
illuminated. This indicates that the front-
passenger front air bag is deactivated. If the
42 indicator lamp does not
light up or goes out when the child restraint50Occupant safetySafety

system is installed, check the anchorages
of the restraint system. Periodically check
the 42 indicator lamp while
driving to make sure the 42
indicator lamp is illuminated. If the
42 indicator lamp goes out or
remains out, you may only carry a child on
the front-passenger seat once the system
has been repaired.
A child in a rearward-facing child restraint
system on the front-passenger seat can be
seriously injured or even killed if the front-
passenger front air bag is deployed.
R When securing a child in a front-facing child
restraint system on the front-passenger
seat, you must:
- move the front-passenger seat as far
back as possible
- use a child restraint system that is
suitable for the age, size and weight of
the child
- observe the manufacturer's installation
instructions in order to install and secure
the child restraint system correctly.GWARNING
When using a BabySmart™-compatible child
restraint system on the front-passenger seat,
the front-passenger front air bag is only
disabled if the 42 indicator lamp
is illuminated.
Check the 42 indicator lamp
repeatedly, every time you use a
BabySmart™-compatible child restraint
system on the front-passenger seat. Should
the 42 indicator lamp not
illuminate or go out while the restraint is
installed, please check installation. If the
42 indicator lamp remains out,
do not use the BabySmart™ child restraint
system to carry a child on the front-passenger
seat until the system has been repaired.
GWARNING
The BabySmart™ air bag disabling system
ONLY works with specially adapted child
restraint systems. It does not work with child
restraint systems that are not compatible with
BabySmart™.
Never place anything between the seat
cushion and the child restraint system (e.g. a
cushion), as this reduces the effectiveness of
the BabySmart™ air bag deactivation system.
The underside of the child restraint system
must lie against the seat cushion of the front-
passenger seat. In the event of an accident,
an incorrectly installed child restraint system
could injure the child instead of offering
protection.
Observe the manufacturer's instructions
when installing special child restraint
systems.
Special child restraint systems which are
compatible with BabySmart™ are necessary
for deactivating the front-passenger front air
bag. When the special child restraint system
which is compatible with BabySmart™ is
installed correctly and is recognized by the
sensor system in the front-passenger seat,
the front-passenger front air bag is
deactivated. In this case, the
42 : indicator lamp
illuminates. If you have any questions
regarding the special child restraint systems
which are compatible with BabySmart™,
consult an authorized Mercedes-Benz
Center.
If the SmartKey has been removed from the
ignition lock or is in position 0, indicator lamp
42 : does not light up.
Occupant safety51SafetyZ

The system does not disable:
R the side impact air bag
R the window curtain air bag
R the Emergency Tensioning Devices/belt
buckle tensioners
System self-test
The 42 indicator lamp
illuminates when you:
R turn the SmartKey to position 1 or 2 in the
ignition lock
R on vehicles with KEYLESS-GO, press the
Start/Stop button once or twice
The 42 indicator lamp goes out
again after approximately six seconds.
If the 42 indicator lamp does not
illuminate or is lit continuously, the system is
malfunctioning. Have the BabySmart™
system checked at an authorized Mercedes-
Benz Center before transporting a child on
the front-passenger seat.
For further information, see "Problems with
air bag deactivation system" ( Y page 53).
GWARNING
Do not place powered-on laptops, mobile
phones, electronic tags such as those used in
ski passes or similar electronic devices on the
front passenger seat. Signals from such
devices may interfere with the BabySmart™
air bag deactivation system. Such signal
interference may cause the 42
indicator lamp not to come on during self-test.
The + SRS indicator lamp and/or the
42 indicator lamp could be
continuously lit, indicating that the system is
not functioning. The front-passenger front air
bag could deploy inadvertently or fail to
deploy in an accident.
52Occupant safetySafety

Problems with air bag deactivation systemProblemPossible causes/consequences and M SolutionsThe 42
indicator lamp lights up
and remains
illuminated.A BabySmart™ compatible child restraint system is installed on
the front-passenger seat.
The front-passenger air bag is therefore disabled.There is no BabySmart™ compatible child restraint system
installed on the front-passenger seat. The BabySmart™ system is
malfunctioning.XHave the BabySmart™ system checked as soon as possible at
an authorized Mercedes-Benz center.GWARNING
If the 42 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,
the system then determines the occupant cannot be a child. Do not allow any occupant to use
the passenger seat until the system has been repaired.
ProblemPossible causes/consequences and M SolutionsThe 42
indicator lamp does not
illuminate or does not
remain illuminated with
a BabySmart™
compatible child
restraint system
properly installed on
the front-passenger
seat.The BabySmart™ system is malfunctioning.XMake sure there is nothing between the seat cushion and the
child seat.XCheck the installation of the child restraint system.XIf the 42 indicator lamp does not illuminate, have
the BabySmart™ system checked as soon as possible at an
authorized Mercedes-Benz Center.
Do not transport a child on the front-passenger seat until the
air bag deactivation system has been repaired.PRE-SAFE ®
(preventative occupant
protection)GWARNING
The PRE-SAFE ®
system reduces the impact of
an accident on vehicle occupants, as long as
their seat belts have been fastened correctly.
Although your vehicle is equipped with a PRE-
SAFE ®
system, the possibility of injury in the
event of an accident cannot be ruled out. You
should therefore always drive carefully and
adapt your driving style to the prevailing road,
weather and traffic conditions.
PRE-SAFE ®
takes preemptive measures to
protect occupants in certain hazardous
situations.
PRE-SAFE ®
intervenes:
R in emergency braking situations when BAS
intervenes
R in critical driving situations, e.g. when
physical limits are exceed and the vehicle
understeers or oversteers severelyOccupant safety53SafetyZ

PRE-SAFE®
takes the following measures
depending on the hazardous situation
detected:
R the front seat belts are pre-tensioned.
R on vehicles with memory function for the
front-passenger seat: the front-passenger
seat is adjusted if it is in an unfavorable
position.
R if the vehicle skids, the side windows are
closed so that only a small gap remains.
R on vehicles with a sliding sunroof: if the
vehicle skids, the sliding sunroof closes so
that only a small gap remains.
If the hazardous situation passes without
resulting in an accident, PRE-SAFE ®
slackens
the belt pretensioning. All settings made by
PRE-SAFE ®
can then be reversed.
If the seat belts are not released:XMove the backrest or seat back slightly, but
only when the vehicle is stationary.
The belt pretensioning is reduced and the
locking mechanism is released.GWARNING
Make sure that nobody can become trapped
as you adjust the seat.
! 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.
More information about seat-belt
adjustment, a convenience function
integrated into PRE-SAFE ®
, can be found in
the "Seat-belt adjustment" section
( Y page 58).
NECK-PRO head restraints
The NECK-PRO head restraints increase
protection to the driver's and front
passenger's head and neck. To this end, the
NECK-PRO head restraints on the driver's and
front-passenger seats are moved forwards
and upwards in the event of a rear-end
collision of a certain severity. This provides
better head support.GWARNING
Do not secure any objects (e.g. coat hangers)
on the NECK-PRO head restraints. Otherwise,
the NECK-PRO head restraints may not
function properly, or in the event of a rear-end
collision may not be able offer the level of
protection they are designed to provide.
If the NECK-PRO head restraints have been
triggered in an accident, reset the NECK-PRO
head restraints on the driver’s and front-
passenger seat ( Y page 54). Otherwise, the
additional protection will not be available in
the event of another rear-end collision. You
can recognize when NECK-PRO head
restraints have been triggered by the fact that
they have moved forwards and can no longer
be adjusted.
Resetting triggered NECK-PRO head
restraints
Important safety notes
GWARNING
For reasons of safety, have the NECK-PRO
head restraints/NECK-PRO luxury head
restraints checked at an authorized
Mercedes-Benz Center after a rear-end
collision.
GWARNING
When pushing back the NECK-PRO head
restraint cushion, make sure your fingers do
not become caught between the head
restraint cushion and the cover. Failure to
observe this could result in injuries.
NECK-PRO head restraints
i Resetting the NECK-PRO head restraints
requires a lot of strength. If you have
difficulty resetting the NECK-PRO head
restraints, have this work carried out at a
54Occupant safetySafety