MERCEDES-BENZ SLK-Class 2014 R172 Service Manual

systems for infants and children, see
"Children in the vehicle" (Y
page 55).SRS (Supplemental Restraint System)
Introduction SRS consists of:
R
The 0075 SRS warning lamp
R Air bags
R The air bag control unit with crash sensors
R Emergency Tensioning Device (ETD) for
seat belts
R Seat belt force limiter
SRS reduces the risk of vehicle occupants
coming into contact with parts of the
vehicle's interior in the event of an accident.
It can also reduce the forces to which vehicle
occupants are subjected during an accident.
SRS warning lamp G
WARNING
If SRS is malfunctioning, child restraint
system components may be triggered
unintentionally or might not be triggered at all
in the event of an accident with a high rate of
vehicle deceleration. There is an increased
risk of injury, possibly even fatal.
Have SRS checked and repaired immediately
at a qualified specialist workshop.
SRS functions are checked regularly when
you switch on the ignition and when the
engine is running. Therefore, malfunctions
can be detected in good time.
The 0075 SRS warning lamp in the instrument
cluster lights up when the ignition is switched
on. It goes out no later than a few seconds
after the engine is started.
The SRS components are in operational
readiness when the 0075SRS warning lamp
goes out while the engine is running. There is a malfunction if:
R
the 0075 SRS warning lamp does not light
up when the ignition is switched on
R the engine is running and the 0075SRS
warning lamp does not go out after a few
seconds
R the engine is running and the 0075SRS
warning lamp lights up again
Safety guidelines for seat belts,
Emergency Tensioning Devices (ETDs)
and air bags G
WARNING
R Damaged seat belts or seat belts that have
been subjected to stress in an accident
must be replaced. Their anchoring points
must also be checked. Only use seat belts
installed or supplied by an authorized
Mercedes-Benz Center.
R Air bags and pyrotechnic Emergency
Tensioning Devices (ETDs) contain
perchlorate material, which may require
special handling and regard for the
environment. Check your national disposal
guidelines. In California, see
www.dtsc.ca.gov/HazardousWaste/
Perchlorate/index.cfm.
R Air bags and ETDs are designed to function
on a one-time-only basis. An air bag or ETD
that has deployed must be replaced.
R Do not pass seat belts over sharp edges.
They could tear.
R Do not make any modification that could
change the effectiveness of the seat belts.
R Do not bleach or dye seat belts, as this may
severely weaken them. In a crash, they may
not be able to provide adequate protection.
R Do not make any modifications to the SRS
wiring or components.
R Do not modify or remove any components
or parts of the SRS. Occupant safety
39Safety
Z

R
Do not install additional trim material, seat
covers, badges, etc. to the:
-padded steering wheel boss
- knee bag covers
- front-passenger air bag cover
- outer side of front seat bolsters
- outer seat bolsters of the rear bench seat
backrest
- roof frame trim
R Do not install additional electrical/
electronic equipment on or near SRS
components and wiring.
R Keep the area between the air bags and
occupants free of objects (e.g. packages,
handbags, umbrellas etc.).
R Do not hang any objects such as coat
hangers on the coat hooks or the grab
handle above the door. These items may be
thrown around in the vehicle and cause
head and other injuries when the window
curtain air bag is deployed.
R Air bag system components will be hot after
an air bag has inflated. Do not touch them.
R Never rest your feet on the dashboard or
the seat. Always keep both feet on the floor
in front of the seat.
R Improper repair work on the SRS creates a
risk of rendering the SRS inoperative or
causing unintended air bag deployment.
Work on the SRS must therefore only be
performed by qualified technicians.
Consult an authorized Mercedes-Benz
Center.
R For your protection and the protection of
others, when scrapping the air bag unit or
ETD, our safety instructions must be
followed. These are available from any
authorized Mercedes-Benz Center.
R Given the considerable deployment speed,
required inflation volume, and the material
of the air bags, there is the possibility of
abrasions or other, potentially more serious
injuries resulting from air bag deployment. If you sell your vehicle, Mercedes-Benz
strongly recommends that you inform the
subsequent owner that the vehicle is
equipped with SRS. Also, refer them to the
applicable section in the Operator's Manual. Air bags
Important safety notes G
WARNING
Using unsuitable seat covers could restrict or
even prevent deployment of the air bags
integrated into the seats. Consequently, the
air bags cannot protect vehicle occupants as
they are designed to do. In addition, the
function of the air bag deactivation system
could be restricted. This poses an increased
risk of injury or even fatal injury.
You should only use seat covers that have
been approved for the respective seat by
Mercedes-Benz. G
WARNING
The air bag parts are hot after the airbag has
been deployed. There is a risk of injury.
Do not touch the air bag parts. Have the
deployed air bags replaced at a qualified
specialist workshop as soon as possible. G
WARNING
Air bags are designed to reduce the incidence
of injuries and fatalities in certain situations:
R frontal impacts (driver's and front-
passenger front air bags and knee bags)
R side impacts (side impact air bags and head
bags)
R rollover (head bags)
However, no system available today can
completely eliminate injuries and fatalities.
When the air bags are deployed, a small
amount of powder is released. The powder
generally does not constitute a health hazard
and does not indicate that there is a fire in the
vehicle. In order to prevent potential 40
Occupant safetySafety

breathing difficulties, you should leave the
vehicle as soon as it is safe to do so. If you
have any breathing difficulty but cannot get
out of the vehicle after the air bag inflates,
then get fresh air by opening a window or
door. G
WARNING
In order to reduce the potential danger of
injuries caused during the deployment of the
front air bags, the driver and front passenger
must always be correctly seated and wear
their seat belts.
For maximum protection in the event of a
collision, you must always be in the normal
seat position with your back against the
backrest. Fasten your seat belt and make sure
that it is correctly positioned on your body.
As 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 fastened correctly and
in a position that is as upright as possible
with your back against the 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 middle of
the air bag cover on the steering wheel
must be at least 10 inches (25 cm). You
should be able to accomplish this by
adjusting the seat and steering wheel. If
you have any difficulties, please contact a
qualified specialist workshop.
R do not lean your head or chest close to the
steering wheel or dashboard.
R only hold the steering wheel on the outside.
Placing hands and arms inside the rim of
the steering wheel can increase the risk and potential severity of hand/arm injuries
if the 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 and/or head bag inflates.
This could result in serious injuries or death
should the side impact air bag/head bag be
deployed. 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.
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. G
WARNING
If the side impact air bag and/or head bag is
deployed in the event of a side impact and the
front passenger, especially a child, is not
properly seated or restrained when next to a
side impact air bag/head bag, injuries are
possible due to the rapid inflation of the side
impact air bag/head bag.
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.
If the air bags are deployed, you will hear a
bang, and a small amount of powder may also
be released. Only in rare cases will the bang Occupant safety
41Safety Z

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 0075SRS
warning lamp lights up.
The air bag installation locations are
identified by the AIR BAG symbol.
The air bags are deployed if the air bag control
unit detects the need for deployment. Only in
the event of such a situation will the air bags
provide their supplemental protection.
If the driver and front passenger do not wear
their seat belts, 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 passenger 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.
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.
i After an air bag has been deployed, have
the vehicle towed to the nearest qualified
specialist workshop, even if your vehicle is
ready to drive. Front air bags
Driver's air bag
0043deploys in front of the
steering wheel; front-passenger front air
bag 0044deploys in front of and above the glove
box.
The front air bags increase protection for the
driver's and front passenger's head and
chest.
They are deployed:
R at the start of an accident with a high rate
of vehicle acceleration or deceleration in a
longitudinal direction
R if the system determines that air bag
deployment can offer additional protection
to that provided by the seat belt
R independently of other air bags in the
vehicle
The release time of the front air bags is
dependant upon the use of the seat belt.
If the vehicle rolls over, the front air bags are
generally not deployed.
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 42
Occupant safetySafety

determined by the Occupant Classification
System (OCS) (Y
page 45).
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 PASSENGER AIR BAG OFF indicator
lamp on the center console is not lit
(Y page 45)
R the air bag control unit predicts a high
impact severity
Knee bags i
Observe the "Important safety notes"
section (Y page 40) Driver's knee bag
0043deploys underneath the
steering column and front-passenger knee
bag 0044underneath 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.
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
Side impact air bags G
WARNING
Using unsuitable seat covers could restrict or
even prevent deployment of the air bags
integrated into the seats. Consequently, the
air bags cannot protect vehicle occupants as
they are designed to do. In addition, the
function of the air bag deactivation system
could be restricted. This poses an increased
risk of injury or even fatal injury.
You should only use seat covers that have
been approved for the respective seat by
Mercedes-Benz. G
WARNING
Sensors to control the air bags are located in
the doors. Modifications or work not
performed correctly to the doors or door
paneling, as well as damaged doors, can lead
to the function of the sensors being impaired.
The air bags might therefore not function
properly any more. Consequently, the air bags
cannot protect vehicle occupants as they are
designed to do. There is an increased risk of
injury.
Never modify the doors or parts of the doors.
Always have work on the doors or door
paneling carried out at a qualified specialist
workshop.
You should only use seat covers that have
been approved for your vehicle by Mercedes-
Benz. The seat covers must have a special
tear seam for side impact air bags. Otherwise,
the side impact air bags cannot deploy
correctly and therefore cannot provide the Occupant safety
43Safety Z

intended protection in the event of an
accident. Example: side impact air bag on the driver's side
Side impact air bags 0043deploy next to the
outer side bolsters of the seat backrest.
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
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 the use of the seat belt
R independently of the front air bags
R independently of the ETDs
If the vehicle rolls over, the side impact air
bags are generally not deployed. Side impact
air bags 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. The side impact air bag on the front-
passenger side does not deploy under the
following conditions:
R
the OCS system detects that the front-
passenger seat is not occupied, and
R the front-passenger seat belt is not
fastened.
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.
Head bags Example: head bag on the front-passenger side
Head bags
0043deploy in the area of the side
windows at the front. Head 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 head bags are deployed:
R at the start of an accident with a high rate
of lateral vehicle deceleration or
acceleration, e.g. in a side impact
R on the side on which an impact occurs
R on the driver's side and passenger side, in
the event of a vehicle rollover and if the
system determines that air bag deployment
can offer the vehicle occupants additional
protection to that provided by the seat belt
R independently of the use of the seat belt
R independently of the front air bags
Head bags will not deploy in side impacts
which do not exceed the system's preset 44
Occupant safetySafety

deployment thresholds for lateral
acceleration/deceleration. You will then be
protected by the fastened seat belt.
The head bag on the front-passenger side is
not deployed in the following situations:
R the OCS system detects that the front-
passenger seat is not occupied, and
R the front-passenger seat belt is not
fastened.
The head 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. Occupant Classification System
(OCS)
Method of operation G
WARNING
If the 0073 PASSENGER AIR BAG OFF
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 0073PASSENGER AIR BAG OFF
indicator lamp goes out.
In the event of a collision, the air bag control
unit will not allow front-passenger front air
bag and front-passenger knee bag
deployment when the OCS has classified the
front-passenger 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
unoccupied.
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 0073PASSENGER AIR BAG OFF
indicator lamp will illuminate when the engine
is started and remain illuminated. This
indicates that the front-passenger front air bag and the front-passenger knee bag are
deactivated.
When the OCS senses that the front-
passenger seat is classified as being empty,
the
0073 PASSENGER AIR BAG OFF indicator
lamp will illuminate when the engine is started
and remain illuminated. This indicates that
the front-passenger front air bag and the
front-passenger knee bag are 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
restraint or as being a small individual (such
as a young teenager or a small adult), the
0073 PASSENGER AIR BAG OFF indicator
lamp will illuminate for approximately 6
seconds when the engine is started.
Depending on occupant weight sensor
readings from the seat, it will then remain
illuminated or go out. If the 0073PASSENGER
AIR BAG OFF indicator lamp is illuminated, the
front-passenger front air bag and the front-
passenger knee bag are deactivated. If the
0073 PASSENGER AIR BAG OFF indicator
lamp is not illuminated, the front-passenger
front air bag and the front-passenger knee
bag are activated.
When the OCS senses that the front-
passenger seat occupant is classified as an
adult or someone larger than a small
individual, the 0073PASSENGER AIR BAG
OFF indicator lamp will illuminate for
approximately six seconds when the engine is
started and then go out. This indicates that
the front-passenger front air bag and the
front-passenger knee bag are activated.
If the 0073 PASSENGER AIR BAG OFF
indicator lamp is illuminated, the front-
passenger front air bag and the front-
passenger knee bag are deactivated and are
not deployed. Occupant safety
45Safety
Z

If the
0073 PASSENGER AIR BAG OFF
indicator lamp is not illuminated, the front-
passenger front air bag and the front-
passenger knee bag are activated and are
deployed:
R in certain front impacts
R independently of the side impact air bag
and head bag
R if the impact has exceeded a
predetermined threshold value for
deployment
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
determined by the OCS G
WARNING
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.
The infant or child restraint must be properly
secured with the vehicle's seat belt fully in
accordance with the child seat
manufacturer's 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 information:
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
system on the front-passenger seat will 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.
R If you must install a rearward-facing child
restraint on the front-passenger seat, make
sure the 0073PASSENGER AIR BAG OFF
indicator lamp is illuminated, indicating
that the front-passenger front air bag and
front-passenger knee bag are deactivated.
If the 0073 PASSENGER AIR BAG OFF
indicator lamp does not light up or goes out
when a rearward-facing child restraint
system is installed, please check
installation. Periodically check the 0073
PASSENGER AIR BAG OFF indicator lamp
while driving to make sure the 0073
PASSENGER AIR BAG OFF indicator lamp is
illuminated. If the 0073PASSENGER AIR
BAG OFF indicator lamp goes out or
remains out do not carry a child on the
front-passenger seat.
R A child in a rearward-facing child restraint
system on the front-passenger seat will be
seriously injured or even killed if the front-
passenger air bag is deployed.
R When securing a child in a 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.
R For children larger than the typical 12-
month-old child, the front-passenger front
air bag may or may not be activated. 46
Occupant safetySafety

G
WARNING
If the red 0075SRS warning lamp in the
instrument cluster and the 0073PASSENGER
AIR BAG OFF 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 as soon
as possible by qualified technicians. Consult
an authorized Mercedes-Benz Center.
Only have the seat repaired at an authorized
Mercedes-Benz Center.
In order to ensure correct operation of the air
bag system and OCS:
R sit with the seat belt fastened correctly and
in a position that is as upright as possible
with your back against the backrest.
R while seated, an occupant should not
position themselves in such a way as to
cause their weight to be lifted from the seat
cushion as this may result in OCS being
unable to correctly assess the occupant's
weight category.
R read and observe all warnings in this
section. 0043
PASSENGER AIR BAG OFF indicator lamp
0044 PASSENGER AIR BAG ON indicator lamp
If the SmartKey is removed from the ignition
lock or is in position 0, PASSENGER AIR BAG
OFF indicator lamp 0043does not light up.
PASSENGER AIR BAG ON indicator lamp 0044
has no function. It lights up briefly when the
ignition is switched on and then goes out
again. Occupant Classification System (OCS)
categories the occupant on the front-
passenger seat using a weight sensor. The
front-passenger front air bag and the front-
passenger knee bag are deactivated
automatically for certain weight categories.
PASSENGER AIR BAG OFF indicator lamp
0043
shows you the current status. If PASSENGER
AIR BAG OFF indicator lamp 0043lights up, 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 front-passenger head 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
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 cushion are damaged, have the
necessary repair work carried out at a
qualified specialist workshop.
Mercedes-Benz recommends that you only
use seat accessories which have been
approved by Mercedes-Benz.
Both the driver and the front passenger
should always observe PASSENGER AIR BAG
OFF indicator lamp 0043as an indication of
whether or not the front passenger is
positioned correctly. Observe also the air bag
display messages that can be displayed in the
instrument cluster (Y page 220).
If the driver's air bag deploys, this does not
mean that the front-passenger front air bag
will also deploy. Occupant safety
47Safety Z

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
and front-passenger knee bag. Deactivation
takes place although the collision fulfills the
criteria for deploying the driver's air bag.
For further information, see "Air bag display
messages" (Y page 220).
System self-test G
WARNING
If the 0073 PASSENGER AIR BAG OFF
indicator lamp does not illuminate, the system
is not functioning. Consult an authorized
Mercedes-Benz Center before seating a child
on the front-passenger seat. G
WARNING
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. 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 adult is 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 again after approximately
6 seconds.
If the seat is 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 about the OCS, see
"Problems with the Occupant Classification
System" (Y page 49). 48
Occupant safetySafety