MERCEDES-BENZ CLS-Class 2012 W218 Service Manual

Since the air bag inflates with considerable
speed and force, a proper seating position
and correct positioning of the hands on the
steering wheel will help to keep you at a safe
distance from the air bag. Occupants who are
not wearing their seat belt, are not seated
properly or are too close to the air bag can be
seriously injured or killed by an air bag as it
inflates with great force instantaneously:
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 Move the driver's seat as far back as
possible, still permitting proper operation
of vehicle controls. The distance from the
center of the driver's chest to the center of
the air bag cover on the steering wheel
must be at least 10 inches (25 cm) or more.
You should be able to accomplish this by
adjusting the seat and steering wheel. If
you have any difficulties, please contact an
authorized Mercedes-Benz Center.
R Do not lean your head or chest close to the
steering wheel or dashboard.
R Only hold the steering wheel by the rim.
Placing hands and arms inside the rim can
increase the risk and potential severity of
hand/arm injury when the driver front air
bag inflates.
R Adjust the front-passenger seat as far back
as possible from the dashboard when the
seat is occupied.
R Occupants, especially children, should
never place their bodies or lean their heads
in the area of the door where the side
impact air bag inflates. This could result in
serious injuries or death should the side
impact air bag be deployed. Always sit as
upright as possible, wear the seat belt
properly and use an appropriately sized
child restraint, infant restraint or booster
seat recommended for the size and weight
of the child.
Failure to follow these instructions can result
in severe injuries to you or other occupants.If you sell your vehicle, it is important that you
make the buyer aware of this safety
information. Be sure to give the buyer this
Operator's Manual.GWARNING
Accident research shows that the safest place
for children in an automobile is in a rear seat.
A side impact air bag related injury may occur
if occupants, especially children, are not
properly seated or restrained when next to a
side impact air bag which needs to deploy
rapidly in a side impact in order to do its job.
To help avoid the possibility of injury, please
follow these guidelines:
(1)Always sit as upright as possible
and use the seat belts properly.
Make sure that children 12 years
old and under use an appropriately
sized child restraint, infant
restraint, or booster seat
recommended for the size and
weight of the child.(2)Always wear seat belts properly.
The air bags are only deployed if the air bag
control unit detects the need for deployment.
Only in the event of such a situation will they
provide their supplemental protection.
The driver and passenger should always wear
their seat belts. Otherwise, it is not possible
for the air bags to provide their supplemental
protection.
In the event of other types of impacts and
impacts below air bag deployment
thresholds, the air bags will not deploy. The
driver and passengers will then be protected
to the extent possible by a properly fastened
seat belt. A properly fastened seat belt is also
needed to provide the best possible
protection in a rollover.
Air bags provide additional protection; they
are not, however, a substitute for seat belts.
All vehicle occupants must fasten their seat
belts regardless of whether your vehicle is
equipped with air bags or not.
Occupant safety39SafetyZ

It is important for your safety and that of your
passenger to have deployed air bags replaced
and to have any malfunctioning air bags
repaired. This will help to make sure the air
bags continue to perform their protective
function for the vehicle occupants in the
event of a crash.
Front air bags
The front air bags increase protection for the
driver's and front-passenger's head and
chest.
Driver's air bag : deploys in front of the
steering wheel; front-passenger front air
bag ; deploys in front of and above the glove
box.
They are deployed:
R in the event of certain frontal impacts
R if the system determines that air bag
deployment can offer additional protection
to that provided by the seat belt
R if the seat belt is fastened
R independently of other air bags in the
vehicle
If the vehicle overturns, the front air bags are
generally not deployed unless the system
detects high vehicle deceleration in a
longitudinal direction.
Your vehicle has adaptive, two-stage front air
bags. In the event of a collision, the air bag
control unit evaluates the vehicle
deceleration. In the first deployment stage,
the front air bag is filled with enough
propellant gas to reduce the risk of injuries.
The front air bag is fully deployed if a second
deployment threshold is exceeded within a
few milliseconds.
The deployment of the front-passenger front
air bag is also influenced by the weight
category of the front passenger, which is
determined by the Occupant Classification
System (OCS) ( Y page 43).
The lighter the passenger side occupant, the
higher the vehicle deceleration rate required
(predicted at the start of the impact) for
second stage inflation of the front-passenger
front air bag. In the second stage, the front
air bags are inflated with the maximum
amount of propellant gas available.
The front air bags are not deployed in
situations where a low impact severity is
predicted. You will then be protected by the
fastened seat belt.
The front-passenger front air bag will only
deploy if:
R the system, based on the OCS weight
sensor readings, detects that the front-
passenger seat is occupied.
R the 45 indicator lamp in the center
console is not lit, ( Y page 43).
R the air bag control unit predicts a high
impact severity.
Knee bagsGWARNING
Observe "Important safety notes"
( Y page 38).
40Occupant safetySafety

Knee bags provide increased protection for
the driver and front passenger against the risk
of:
R knee injuries
R thigh injuries
R lower leg injuries
Driver's knee bag : deploys underneath the
steering column and front-passenger knee
bag ; underneath the glove box. They
deploy together with the front air bags. They
are designed to operate together with the
front air bags in frontal impacts if certain
thresholds are exceeded. The knee bags
operate at best in conjunction with correctly
positioned and fastened seat belts.
Side impact air bagsGWARNING
The pressure sensors for side impact air bag
control are located in the doors. Do not
modify any components of the doors or door
trim panels including, for example, the
addition of door speakers.
Improper repair work on the doors or the
modification or addition of components to the
doors create a risk of rendering the side
impact air bags inoperative or causing
unintended air bag deployment. Work on the
doors must therefore only be performed by
qualified technicians. Contact an authorized
Mercedes-Benz Center.
GWARNING
Only use seat covers which have been tested
and approved by Mercedes-Benz for your
vehicle model. Using seat covers or other seat
coverings can cause a malfunction of the side
impact air bags and/or the pelvis air bags.
Contact an authorized Mercedes-Benz Center
for availability.
When deployed, the side impact air bags offer
additional protection for the thorax of the
vehicle occupants on the side of the vehicle
on which the impact occurs. However, they
do not protect the:
R head
R neck
R arms
Front side impact air bags : and rear side
impact air bags ; deploy next to the outer
seat cushions.
The side impact air bags are deployed:
R on the side on which an impact occurs
R at the start of an accident with a high rate
of lateral vehicle deceleration or
acceleration, e.g. in a side impact
R independently of seat belt use
R independently of the front air bags
R independently of the ETDs
If the vehicle overturns, the side impact air
bags are generally not deployed. They are
deployed if the system detects high vehicle
deceleration or acceleration in a lateral
direction and determines that side impact air
bag deployment can offer additional
protection to that provided by the seat belt.
Side impact air bags will not deploy in side
impacts which do not exceed the system's
preset deployment thresholds for lateral
acceleration/deceleration. You will then be
protected by the fastened seat belt.
If the OCS detects that the front-passenger
seat is not occupied and the front-passenger
seat belt is not fastened (the belt tongue is
Occupant safety41SafetyZ

not engaged in the seat belt buckle), the side
impact air bag on the front-passenger side
will not deploy. The side impact air bag on the
front-passenger side will deploy if the front-
passenger seat belt is fastened, regardless of
whether the front-passenger seat is occupied
or not.
Pelvis air bagsGWARNING
Only use seat covers which have been tested
and approved by Mercedes-Benz for your
vehicle model. Using seat covers or other seat
coverings can cause a malfunction of the side
impact air bags and/or the pelvis air bags.
Contact an authorized Mercedes-Benz Center
for availability.
Pelvis air bag deployment enhances the level
of protection of the vehicle occupants on the
side of the vehicle on which the impact
occurs.
Pelvis air bags : deploy next to and below
the outer seat cushions. They are deployed:
R on the side on which an impact occurs
R at the start of an accident with a high rate
of lateral vehicle deceleration or
acceleration, e.g. in a side impact
R independently of seat belt use
R independently of the front air bags
R independently of the ETDs
The pelvis air bags are generally not deployed
if the vehicle overturns, unless the system
detects high vehicle deceleration or
acceleration in a lateral direction and
determines that they can offer additional
protection to that provided by the seat belt.
Pelvis air bags : will not deploy in side
impacts which do not exceed the system's
preset deployment thresholds for lateral
acceleration/deceleration. You will then be
protected by the fastened seat belt.
Vehicles with OCS (USA only): if the OCS
detects that the front-passenger seat is not
occupied and the front-passenger seat belt is
not fastened (the belt tongue is not engaged
in the seat belt buckle), the pelvis air bag on
the front-passenger side will not deploy. The
pelvis air bag on the front-passenger side will
deploy if the front-passenger seat belt is
fastened, regardless of whether the front-
passenger seat is occupied or not.
Window curtain air bags
The window curtain air bags enhance the level
of protection for the head, but not chest or
arms, of the vehicle occupants on the side of
the vehicle on which the impact occurs.
The window curtain air bags are integrated
into the side of the roof frame and deploy in
the area from the A-pillar to the C-pillar.
Window curtain air bags : are deployed:
R on the side on which an impact occurs
R at the start of an accident with a high rate
of lateral vehicle deceleration or
acceleration, e.g. in a side impact
R regardless of whether the front-passenger
seat is occupied
42Occupant safetySafety

Rindependently of seat belt use
R if the vehicle overturns and the system
determines that window curtain air bag
deployment can offer additional protection
to that provided by the seat belt
R independently of the front air bags
Window curtain air bags : will not deploy in
impacts with deceleration rates which do not
exceed the system's preset deployment
thresholds for vehicle deceleration or
acceleration. You will then be protected by
the fastened seat belt.
Occupant Classification System
(OCS)
How the occupant classification
system works
The Occupant Classification System (OCS)
categorizes the occupant on the front-
passenger seat by means of a weight sensor.
The front-passenger front air bag and the
front-passenger knee bag are deactivated
automatically for certain weight categories.
The 45 indicator lamp shows you the
current status. When the 45 indicator
lamp is illuminated, the front-passenger front
air bag and the front-passenger knee bag are
deactivated.
The system does not deactivate:
R the side impact air bag
R the pelvis air bag
R the window curtain air bag
R the Emergency Tensioning Devices
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
If the front-passenger's weight is transferred
to another object in the vehicle (e.g. by
leaning on armrests), OCS may not be able to
approximate the occupant's weight category.
If the front-passenger seat, the seat cover or
the seat cushion are damaged, have the
necessary repair work carried out at an
authorized Mercedes-Benz Center.
For safety reasons, Mercedes-Benz
recommends that you only use seat
accessories which have been approved by
Mercedes-Benz.
Both the driver and the passenger should
always use the 45 indicator lamp as
an indication of whether or not the passenger
is properly positioned.GWARNING
If the 45 indicator lamp illuminates
when an adult or someone larger than a small
individual is in the front-passenger seat, have
the front passenger reposition himself or
herself in the seat until the 45
indicator lamp goes out.
In the event of a collision, the air bag control
unit will not allow front-passenger front air
bag deployment when 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 45 indicator lamp will
illuminate 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-
passenger seat is classified as being empty,
the 45 indicator lamp will illuminate
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-
passenger seat occupant is classified as
being heavier than the weight of a typical 12-
month-old child seated in a standard child
Occupant safety43SafetyZ

restraint or as being a small individual (such
as a young teenager or a small adult), the
45 indicator lamp will illuminate for
approximately 6 seconds when the engine is
started and then, depending on occupant
weight sensor readings from the front-
passenger seat, remain illuminated or go out.
With the 45 indicator lamp
illuminated, the front-passenger front air bag
is deactivated. With the 45 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 45 indicator lamp will
illuminate 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 45 indicator lamp is illuminated,
the front-passenger front air bag and the
front-passenger knee bag are deactivated and
will not be deployed.
If the 45 indicator lamp is not
illuminated, the front-passenger front air bag
and the front-passenger knee bag are
activated and will be deployed:
R in the event of certain frontal impacts
R if impact exceeds a preset deployment
threshold
R independently 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 relevant vehicle deceleration as
assessed by the air bag control unit
R the front passenger's weight category as
identified by OCS
For further information, see "Air bag display
messages" ( Y page 223).GWARNING
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 ISOFIX
child seat retaining loops and Top Tether
strap, fully in accordance with the infant or
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 if it
is necessary to carry a child on the front-
passenger seat:
R Your vehicle is equipped with air bag
technology designed to deactivate the
front-passenger front air bag and the front-
passenger knee 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 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 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-
44Occupant safetySafety

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
45 indicator lamp is illuminated,
indicating that the front-passenger front air
bag and front-passenger knee bag are
deactivated. Should the 45
indicator lamp not illuminate or go out while
the restraint is installed, please check
installation. Periodically check the
45 indicator lamp while driving to
make sure that the 45 indicator
lamp is illuminated. If the 45
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 could be seriously
injured or even killed if the front-passenger
front air bag is deployed.
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 and the front-passenger knee bag
may or may not be activated.
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
and front-passenger knee 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
45 : does not light up.
GWARNING
If the red 6 SRS warning lamp in the
instrument cluster and the 45
indicator lamp light up simultaneously, the
OCS is malfunctioning. The front passenger
front air bag and the front passenger knee 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 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
Occupant safety45SafetyZ

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 45 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
If an adult occupant is properly sitting on the
passenger seat and the OCS classifies the
occupant as an adult, the 45 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 45 indicator lamp
will illuminate and not go out.
GWARNING
If the 4 5 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 47).
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.46Occupant safetySafety

Problems with the occupant classification systemProblemPossible causes/consequences and M SolutionsThe 45
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 223).GWARNING
If the 45 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.
ProblemPossible causes/consequences and M SolutionsThe 45
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.XIf the 45 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 223).GWARNING
If the 45 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.
Occupant safety47SafetyZ

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, e.g. if BAS
is activated or, in vehicles with DISTRONIC
PLUS, BAS PLUS intervenes powerfully
R if the radar sensor system detects an
imminent danger of collision in certain
situations (on vehicles with DISTRONIC
PLUS)
R in critical driving situations, e.g. when
physical limits are exceed and the vehicle
understeers or oversteers severely
PRE-SAFE ®
takes the following measures
depending on the hazardous situation
detected:
R the front seat belts are pre-tensioned.
R it adjusts the front-passenger seat if it is in
an unfavorable position.
R vehicles with a multicontour seat or an
active multicontour seat: the air pressure
in the side bolsters on the seat cushion and
the side bolsters on the backrest is
increased.
R if the vehicle skids, the sliding sunroof/
panorama roof with power tilt/sliding
panel and the side windows are closed so
that only a small gap remains.
If the hazardous situation passes without
resulting in an accident, PRE-SAFE ®
slackens
the belt pretensioning. The air pressure in the
side bolsters on the multicontour seat/active
multicontour seat is reduced again. 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 53).
NECK-PRO head restraints/NECK-
PRO luxury head restraints
NECK-PRO head restraints/NECK-PRO luxury
head restraints increase protection of the
driver's and front-passenger's head and
neck. In the event of a rear collision of a
certain severity, the NECK-PRO head
restraints/NECK-PRO luxury head restraints
on the driver's and front-passenger seats are
moved forwards and upwards. This provides
better head support.
GWARNING
Do not attach any objects (e.g. a coat hanger)
to the NECK-PRO head restraints/NECK-PRO
luxury head restraints. Otherwise, the NECK-
PRO head restraints/NECK-PRO luxury head
restraints may not function properly and in
the event of a rear-end collision may not offer
the protection they are designed to provide.
48Occupant safetySafety