cluster MERCEDES-BENZ SL-Class 2001 R129 Service Manual

53 Restraint systems
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cluster displayPractical hints Car care Index Seat belt nonusage warning system
With the key in steering lock position 2, a warning
sounds for a short time if the driver’s seat belt is not
fastened.
BabySmart
TM is a trademark of Siemens Automotive Corp.
Wa r n i n g !
Failure to wear and properly fasten and position
your seat belt greatly increases your risk of
injuries and their likely severity in an accident.
You and your passenger should always wear seat
belts.If you are ever in an accident, your injuries can be
considerably more severe without your seat belt
properly buckled. Without your seat belt buckled,
you are much more likely to hit the interior of the
vehicle or be ejected from it. You can be seriously
injured or killed.In the same crash, the possibility of injury or death
is lessened if you are wearing your seat belt.Never let more people ride in the vehicle than there
are seat belts available. Be sure everyone riding in
the vehicle is correctly restrained with a separate
seat belt.
Wa r n i n g !
Children 12 years old and under must never ride in
this vehicle, except in a Mercedes-Benz authorized
BabySmart
TM compatible child seat, which operates
with the BabySmart
TM system installed in the
vehicle to deactivate the passenger side front
airbag when it is properly installed. Otherwise they
will be struck by the airbag when it inflates in a
crash. If this happens, serious or fatal injury can
result.
Infants and small children must be seated in an
appropriate infant or child restraint system, which
is properly secured with the vehicle’s seat belt,
fully in accordance with the child seat
manufacturer’s instructions.A child’s risk of serious or fatal injuries is
significantly increased if the child restraints are
not properly secured in the vehicle and the child is
not properly secured in the child restraint.

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Fastening of seat belts1Latch plate
2Buckle
3Release button
Pull belt with latch plate (1) across shoulder and lap.
Push latch plate (1) into buckle (2) until it clicks.
To help avoid severe or fatal injuries, the lap belt should
be positioned as low as possible on your hips and not
across the abdomen.
Do not twist the belt. A twisted seat belt may cause
injury.
Wa r n i n g !
Always fasten your seat belt before driving off.
Always make sure your passenger is properly
restrained.

55 Restraint systems
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cluster displayPractical hints Car care Index Press switch (4) to adjust the height of the seat belt
outlet so that the shoulder portion is located as close as
possible to the middle of your shoulder.
The shoulder portion of the seat belt must be pulled
snug and checked for snugness immediately after
engaging it and during driving. Tighten the lap portion
to a snug fit by pulling shoulder portion up.Operation of seat belts
The inertia reel stops the belt from unwinding during
sudden vehicle stops or when quickly pulling on the
belt.
The locking function of the reel may be checked by
quickly pulling out the belt.
3
2
1
P91.40-0346-26
4

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Caution!
For safety reasons, avoid adjusting the seat or backrest
into positions which could affect the correct seat belt
positioning.
Unfastening of seat belts
Push the release button (3) in the belt buckle (2).
Allow the retractor to completely rewind the seat belt by
guiding the latch plate (1).
Wa r n i n g !
USE SEAT BELTS PROPERLY.• Each occupant should wear their seat belt at all
times, because seat belts help reduce the
likelihood of and potential severity of injuries
in accidents, including rollovers. The
integrated restraint system includes “SRS”
(driver airbag, passenger airbag, door mounted
side impact airbags), “ETR” (seat belt
emergency tensioning retractors), and front
seat knee bolsters. The system is designed to
enhance the protection offered to properly
belted occupants in certain frontal (front
airbags) and side (side impact airbags) impacts
which exceed preset deployment thresholds.• Never wear belts over rigid or breakable
objects in or on your clothing, such as
eyeglasses, pens, keys etc., as these might
cause injuries.• Position the lap belt as low as possible on your
hips and not across the abdomen. If the belt is
positioned across your abdomen, it can cause
serious injuries in a crash.

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• Never wear the shoulder belt under your arm,
against you neck or off your shoulder. In a
crash, your body would move too far forward.
That would increase the chance of head and
neck injuries. The belt would also apply too
much force to the ribs or abdomen, which
could severely injure internal organs such as
your liver or spleen.• Each seat belt must never be used for more
than one person at a time. Do not fasten a seat
belt around a person and another person or
other objects.• Belts should not be worn twisted. In a crash,
you wouldn’t have the full width of the belt to
manage impact forces. The twisted belt against
your body could cause injuries.• Pregnant women should also use a lap-
shoulder belt. The lap belt portion should be
positioned as low as possible on the hips to
avoid pressure on the abdomen.• Never place your feet on the instrument panel
or on the seat. Always keep both feet on the
floor in front of the seat.
Wa r n i n g !
USE CHILD RESTRAINTS PROPERLY.
Children 12 years old and under must never ride in
this vehicle, except in a Mercedes-Benz authorized
BabySmart
TM compatible child seat, which operates
with the BabySmart
TM system installed in the
vehicle to deactivate the passenger side front
airbag when it is properly installed. Otherwise they
will be struck by the airbag when it inflates in a
crash. If this happens, serious or fatal injury will
result.
Infants and small children must be seated in an
appropriate infant or child restraint system, which
is properly secured with the vehicle’s seat belt,
fully in accordance with the child seat
manufacturer’s instructions.A child’s risk of serious or fatal injuries is
significantly increased if the child restraints are
not properly secured in the vehicle and the child is
not properly secured in the child restraint.Adjust the passenger seat as far as possible
rearward from the dashboard when the seat is
occupied.

58 Restraint systems
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BabySmart
TM airbag deactivation system
Special BabySmart
TM compatible child seats, designed
for use with the Mercedes-Benz system and available at
any authorized Mercedes-Benz Center are required for
use with the BabySmart
TM airbag deactivation system.
With the special child seat properly installed, the
passenger side front airbag will not deploy. The 7
indicator lamp located in the dashboard will be
illuminated, except with key removed or in steering lock
position 0. The system does not deactivate the door
mounted side impact airbag.Self-test BabySmart
TM
without special child seat installed
After turning key in steering lock to position 1 or 2, the
7 indicator lamp located in the dashboard comes on
for approx. 6 seconds and then extinguishes.
If the indicator lamp should not come on or is
continuously lit, the system is not functioning. You must
see an authorized Mercedes-Benz Center before seating
any child on the front passenger seat.BabySmart
TM is a trademark of Siemens Automotive Corp.
Wa r n i n g !
The BabySmart
TM airbag deactivation system will
ONLY work with a special child seat designed to
operate with it. It will not work with child seats
which are not BabySmart
TM compatible.
Never place anything between seat cushion and
child seat (e.g. pillow), since it reduces the
effectiveness of the deactivation system.Follow the manufacturer’s instructions for
installation of special child seats.The passenger front airbag will not deploy only if
the 7 indicator lamp remains illuminated.
Please be sure to check the indicator every time
you use the special system child seat.
Should the light go out while the restraint is
installed, please check installation. If the light
remains out, do not use the BabySmart
TM restraint
to transport children on the front passenger seat
until the system has been repaired.

59 Restraint systems
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cluster displayPractical 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
• first threshold exceeded:
airbag activates, but not ETR
Driver and passenger systems operate independently of
each other.Emergency tensioning retractor (ETR)
The seat belts are equipped with emergency tensioning
retractors. These tensioning retractors are located in
each belt’s inertia reel and become operationally ready
with the key in steering lock position 1 or 2.
The emergency tensioning retractors are designed to
activate only when the seat belts are fastened during
frontal and front-angled impacts and rear impacts
exceeding the first threshold of the SRS and in rear
impacts exceeding a preset severity level. 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, rollovers, certain side
impacts, rear collisions or other accidents without
sufficient frontal or rear impact forces, the emergency
tensioning retractors will not be activated. The driver
and passenger will then be protected by the fastened
seat belts and inertia reel in the usual manner.
For seat belt and emergency tensioning retractor safety
guidelines see page 67.

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Airbags 1Driver airbag
2Passenger front airbag
3Side impact airbags
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 passenger airbags can provide increased protection
for the driver and passenger in certain frontal impacts
exceeding preset thresholds. Door mounted side impact
airbags can provide increased protection to belted
occupants on the impacted side of the vehicle in side
impacts exceeding its preset thresholds.
The operational readiness of the airbag system is
verified by the indicator lamp "SRS" in the instrument
cluster when turning the key in steering lock to
position 2. If no fault is detected, the lamp will go out
after approximately 4 seconds: 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

61 Restraint systems
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cluster displayPractical hints Car care Index come on at all or if it fails to extinguish after
approximately 4 seconds or if it comes on thereafter, a
malfunction in the system has been detected.
The following system components are monitored or
undergo a selfcheck: crash-sensor(s), airbag ignition
circuits, seat belt buckles, emergency tensioning
retractors, seat sensor.
Initially, when the key is turned from steering lock
position 0 to positions 1 or 2, malfunctions in the crash-
sensor are detected and indicated (the “SRS” indicator
lamp stays on longer than 4 seconds or does not come
on). 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 passenger seat belt buckle harnesses, and
low voltage in the entire system are detected and
indicated.Have the system checked at your authorized
Mercedes-Benz Center immediately.
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 unnecessary which could also
result in injury.

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Front airbags
The driver and passenger front airbags are designed to
activate only in certain frontal impacts exceeding a
preset threshold.
The passenger front airbag deploys only if the front
passenger seat is occupied, and the 7 indicator lamp
in the dashboard is not illuminated.
Note:
Heavy objects on the 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.Side impact airbags
The side impact airbags are designed to activate only in
certain side impacts exceeding a preset threshold. Only
the side impact airbag on the impacted side of the
vehicle deploy.
The passenger side impact airbag deploys only if the
passenger seat is occupied.
Side impact airbags operate best in conjunction with a
properly positioned and fastened seat belt.
Note:
Heavy objects on passenger seat can cause the
passenger door side impact airbag to deploy in a crash.
Important!
Airbags are designed to activate only in certain
frontal (front airbags) impacts, or side (side impact
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 must always wear their
seat belts, otherwise it is not possible for the airbags
to provide their intended supplemental protection.