2002 MERCEDES-BENZ C-CLASS display

70
Restraint systems
Te ch n i c a l
data
Instruments
and controls Operation
DrivingInstrument
cluster display Practical hints Car care Index
Supplemental Restraint System (SRS)
Airbags are intended as a supplement to seat belts.
Airbags alone cannot protect as well as airbags plus
seat belts in impacts for which the airbags were
designed to operate, and do not afford any protection
whatsoever in crashes for which the airbags are not
designed to deploy.
The SRS uses two crash severity levels (thresholds) to
activate either the emergency tensioning retractor (ETR)
or front airbag or both. Activation depends on the
direction and severity of the impact exceeding the
preset thresholds and whether the seat belt is fastened. Seat belt fastened
• first threshold exceeded: ETR activates
• second threshold exceeded: airbag also activates
Seat belt not fastened
Front seats: • first threshold exceeded: airbag activates, not ETR
Rear seats: • first threshold exceeded: ETR activates
Driver and front passenger and rear seat systems
operate independently of each other.
ProCarManuals.com

71
Restraint systems
Te ch n i c a l
data
Instruments
and controls Operation
DrivingInstrument
cluster display Practical hints Car care Index
Emergency tensioning retractor (ETR)
The seat belts for the front and rear seats are equipped
with emergency tensioning retractors. These tensioning
retractors are located in each belt’s inertia reel and
become operationally ready with the electronic key in
starter switch position 1 or 2.
The emergency tensioning retractors are designed to
activate only when the seat belts are fastened during
frontal impacts exceeding the first threshold of the SRS
They remove slack from the belts in such a way that the
seat belts fit more snugly against the body restricting its
forward movement as much as possible.
In cases of other frontal impacts, angled impacts, roll-
overs, certain side impacts, or other accidents without
sufficient frontal or rear impact forces, the emergency
tensioning retractors will not be activated. The driver
and passengers will then be protected by the fastened
seat belts and inertia reel in the usual manner.
Note:
The front passenger ETR activates only if the front
passenger seat is occupied.
Heavy objects on the front passenger seat can appear to
the “SRS” to indicate the presence of an occupant in
that seat which causes the passenger front airbag to
deploy and the ETR to activate in a crash exceeding the
appropriate threshold.
ProCarManuals.com

72
Restraint systems
Te ch n i c a l
data
Instruments
and controls Operation
DrivingInstrument
cluster display Practical hints Car care Index
Airbags
Front airbags
1 Driver airbag
2 Front passenger airbag The most effective occupant restraint system yet
developed for use in production vehicles is the seat belt.
In some cases, however, the protective effect of a seat
belt can be further enhanced by an airbag.
In conjunction with wearing the seat belts, the driver
and front passenger airbags can provide increased
protection for the driver and front passenger in certain
frontal impacts exceeding preset thresholds.
Side impact and head protection window curtain airbags
can provide increased protection to belted occupants on
the impacted side of the vehicle in side impacts
exceeding its preset threshold.
ProCarManuals.com

73
Restraint systems
Te ch n i c a l
data
Instruments
and controls Operation
DrivingInstrument
cluster display Practical hints Car care Index
The operational readiness of the airbag system is
verified by the indicator lamp “SRS” in the instrument
cluster when turning the electronic key in starter switch
to position 1. When turning the electronic key in starter
switch to position 2 the indicator lamp “SRS” in the
instrument cluster comes on. If no fault is detected, the
lamp will go out when the engine is running. After the
lamp goes out, the system continues to monitor the
components and circuitry of the airbag system and will
indicate a malfunction by coming on again. If the lamp
does not come on at all or if it fails to extinguish or if it
comes on thereafter, a malfunction in the system has
been detected.
The following system components are monitored or
undergo a self-check: crash-sensor(s), airbag ignition
circuits, front seat belt buckles, emergency tensioning
retractors, seat sensor.
Have the system checked at your authorized
Mercedes-Benz Center immediately.
In the operational mode, after the indicator lamp has
gone out following the initial check, interruptions or
short circuits in the airbag ignition circuit and in the
driver and front passenger seat belt buckle harnesses,
and low voltage in the entire
system are detected and
indicated. Note:
See page 285 for information on the supplemental
restraint system (SRS) indicator lamp.
Wa r n i n g !
In the event a malfunction of the “SRS” is indicated
as outlined above, the “SRS” may not be
operational. For your safety, we strongly
recommend that you visit an authorized
Mercedes-Benz Center immediately to have the
system checked; otherwise the “SRS” may not be
activated when needed in an accident, which could
result in serious or fatal injury, or it might deploy
unexpectedly and unnecessarily which could also
result in injury.
ProCarManuals.com

74
Restraint systems
Te ch n i c a l
data
Instruments
and controls Operation
DrivingInstrument
cluster display Practical hints Car care Index
The driver and passenger front airbags are designed to
activate only in certain frontal impacts exceeding a
preset threshold. The front passenger airbag deploys
only if the front passenger seat is occupied and the
ü indicator lamp in the center console is not
illuminated. Note:
Heavy objects on the front passenger seat can appear to
the “SRS” to indicate the presence of an occupant in
that seat which causes the passenger front airbag to
deploy in a crash exceeding the appropriate threshold.
ProCarManuals.com

75
Restraint systems
Te ch n i c a l
data
Instruments
and controls Operation
DrivingInstrument
cluster display Practical hints Car care Index
Side impact airbags, window curtain airbags
3 Side impact airbags
4 Window curtain airbags Side impact airbags
The side impact airbags are designed to activate only in
certain side impacts exceeding a preset threshold. Only
the side impact airbags on the impacted side of the
vehicle deploy.
The side impact airbag for the front passenger deploys
only if the front passenger seat is occupied.
The side impact airbag for the right rear passenger
deploys only if a preset threshold is exceeded. The side
impact airbag for the left rear passenger deploys
together with the side impact airbag for the driver.
Side impact airbags operate best in conjunction with a
properly positioned and fastened seat belt.
Note:
Heavy objects on front passenger seat can cause the
front passenger side impact airbag to deploy in a crash.
ProCarManuals.com

76
Restraint systems
Te ch n i c a l
data
Instruments
and controls Operation
DrivingInstrument
cluster display Practical hints Car care Index
Window curtain airbag
The head protection window curtain airbags afford
greater protection against injuries to the head and
upper body. They fill up in the area between the A and
C pillars (see arrows) between the side windows and an
occupant’s head.
The window curtain airbags are designed to activate
only in certain side impacts exceeding a preset
threshold. Only the head protection window curtain
airbag on the impacted side of the vehicle deploys. Important!
Airbags are designed to activate only in certain
frontal (front airbags) impacts, or side (side impact
and head protection window curtain airbags)
impacts which exceed preset thresholds.
Only during these types of impacts, if of sufficient
severity to meet the deployment thresholds, will
they provide their supplemental protection.
The driver and passenger should always wear their
seat belts, otherwise it is not possible for the airbags
to provide their supplemental protection.
In cases of other frontal impacts, angled impacts,
roll-overs, other side impacts, rear collisions, or
other accidents, the airbags will not be activated.
The driver and passengers will then be protected by
the fastened seat belts.
We caution you not to rely on the presence of the
airbags in order to avoid wearing your seat belt.
ProCarManuals.com

77
Restraint systems
Te ch n i c a l
data
Instruments
and controls Operation
DrivingInstrument
cluster display Practical hints Car care IndexYour vehicle was originally equipped with airbags
which are designed to activate in certain impacts
exceeding a preset threshold to reduce the potential
and severity of injury. It is important to your safety
and that of your passenger that you replace deployed
airbags and repair any malfunctioning airbags to
ensure the vehicle will continue to provide crash
protection for occupants.
Wa r n i n g !
Airbags are designed to reduce the potential of
injury in certain frontal (front airbags) impacts, or
side (side impact and head protection window
curtain airbags) impacts which may cause
significant injuries, however, no system available
today can totally eliminate injuries and fatalities.The activation of the “SRS” temporarily releases a
small amount of dust from the airbags. This dust,
however, is neither injurious to your health, nor
does it indicate 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. If you have any breathing
difficulty but cannot get out of the vehicle after the
airbag inflates, then get fresh air by opening a
window or door.
Wa r n i n g !
To reduce the risk of injury when the front airbags
inflate, it is very important for the driver and front
passenger to always be in a properly seated
position and to wear your seat belt.For maximum protection in the event of a collision
always be in normal seated position with your back
against the backrest. Fasten your seat belt and
ensure that it is properly positioned on your body.Since the airbag inflates with considerable speed
and force, a proper seating and hands on steering
wheel position will help to keep you at a safe
distance from the airbag. Occupants who are
unbelted, out of position or too close to the airbag
can be seriously injured by an airbag as it inflates
with great force in the blink of an eye:
ProCarManuals.com