MERCEDES-BENZ C-Class 2000 W202 Service Manual

Supplemental Restraint System (SRS)

The term Supplemental Restraint System means that 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 system is not designed to deploy. The SRS us es two crash severity levels (thresholds) to
activate either the Emergency tensioning retrac tor (ETR) or airbag or both. Activation depends on
the direction and severity of the impact, exceedi ng the thresholds and fastening of the seat belt.

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 front passenger systems opera te independently from each other.

Emergency Tensioning Retractor (ETR)

The seat belts for the front 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 steering lock 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 and in rear impacts exceeding a preset security 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, angled impacts, roll-overs, certain
side impacts, or other accidents without sufficient frontal or rear impact forces, the emergency
tensioning retractors will not be ac tivated. The driver and passengers 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 Safety Guidelines in Index.

Airbags

1. Driver airbag
2. Front passenger airbag
3. Side impact 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. The driver airbag is located
in the steering wheel hub. The passenger airbag is located in the dashboard ahead of the passenger.
The side impact airbags are located in the front doors. In conjunction with wearing the seat belts with emergency
tensioning retractors, the airbags can provide increased protection for the driver and passenger in certain major
frontal (for front airbags) and side impacts (for side impact airbags). The operational readiness of the airbag system is
verified by the indicator lamp "SRS" in the instrument cluster when turning the electronic key in steering lock to
position 1 or 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.
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 . Initially, when the electronic 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). Have the system checked at your authorized
Merzedes-Benz dealer 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 passenger seat belt buckle
harnesses, and low voltage in the entire system are detected and indicated.

Warning !
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 dealer 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.


Front Airbags
The driver and passenger front "SRS" airbags are designed to activate only in certain frontal impacts.
The front passenger airbag deploys only if the front passenger seat is occupied and the indicator lamp on the
center console is not illuminated.

Note:
Heavy objects on front passenger seat can cause the passenger front airbag to deploy in a crash.


Side Impact Airbags
The side impact "SRS" airbags are designed to activate only in certain side impacts. Only the side impact airbag on
the impacted side of the vehicle deploys. The side impact airbag for the front passenger deploys only if the front
passenger
seat is occupied. 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 side impact airbag to deploy in a crash.

Important !
The "SRS" airbags are designed to activate only in certain frontal (front airbags) impacts, or side (side
airbags) impacts. 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 the
seat belts, otherwise it is not possible for the airbags to provide their intended supplemental protection. In
cases of other frontal impacts, angled impacts, roll-overs, other side impacts, rear collisions, or other
accidents without sufficient forces, the airbag 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 an airbag in order to
avoid wearing your seat belt. The "SRS" is designed to re duce the potential of injury in certain frontal (front
airbags) impacts, and side (side impact 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 service life of the
airbags extends to the date indicated on the label located on the driverside door latch post. To provide
continued reliability after that date, they should be inspected by an authorized Mer cedes-Benz dealer at that
time and replaced when necessary.
Your vehicle was originally equippend with a Suppleme ntal Restraint system (SRS). The SRS airbags are
designet to activate in centrain impacts exceeding a preset treshold to reduce the potential and severity of
injury.merzedes-Benz encourages you to replace deploy ed airbags and repair any malfunktioning airbags to
ensure the vehicle will continue to provid e maximum crash protections for occupants.


Warning!
It is very important for your safety 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 the body. Since the airbag
inflates with considerable speed and force, a proper seating and hands on steering wheel position will help
to keep you in a safe distance from the airbag:
• Sit properly belted in an upright position with your back against the seat back.
• Adjust the driver seat as far as possible rearward , still permitting proper operation of vehicle controls.
• Do not lean with your head or chest close to the steering wheel or dashboard.
• Keep hands on the outside of steering wheel rim. Placing hands and arms inside the rim can increase the
risk and potential severity of hand/arm injury when the driver front airbag inflates.
• Adjust the front passenger seat rearward as far as possible from the dashboard when the seat is occupied.
• Children 12 years old and under must never ride in
the front seat, except in a Mercedes-Benz authorized BabySmart™ compatible child seat, which operates
with the BabySmart™ 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 . Failure to follow these instructions can result in severe
injuries to you or other occupants.

Safety Guidelines for the Seat Belt, Emergency Tensioning Retractor and Airbag

Warning !
• Damaged belts or belts that were highly stressed in an accident must be replaced and their anchoring
points must also be checked. Use only belts installed or supplied by an authorized Mercedes-Benz dealer.
• Do not pass belts over sharp edges.
• Do not make any modification that could change the effectiveness of the belts.
• The "SRS" is designed to function on a one-time-only b asis. An airbag or emergency tensioning retractor
(ETR) that was activated must be replaced.
• No modifications of any kind may be made to any components or wiring of the "SRS". This includes
the installation of additional trim material, ba dges etc. over the steering wheel hub, front passenger
airbag cover, or front door trim panels, and in stallation of additional electrical/electronic equipment on
or near "SRS" components and wiring. Keep area between airbags and occupants free of objects
( e.g. packages purses, umbrellas, etc.).
• An airbag system component within the steering wheel gets hot
after the airbag has inflated.
• Improper work on the system, including incorrect
installation and removal, can lead to possible injury
through an uncontrolled activation of the "SRS".
• In addition, through improper work there is the risk of rendering the "SRS" inoperative. Work on the
"SRS" must therefore only be performed by an authorized Mercedes-Benz dealer
• When scrapping the airbag unit or emergency tensioning retractor, it is mandatory to follow our safety
instructions. These instructions are av ailable at your authorized Merzedes-Benz
• Depending on the considerable deployment speed and the textile structure of the airbags, there is the

possibility of light skin abrasions.

When you sell the vehicle we strongly urge you to give notice to the subsequent owner that it is equipped with an
"SRS" by alerting him to the applicable section in the Owner's Manual.

Infant and Child Restraint Systems
We recommend that all infants and children be properly restrained at all times while the vehicle is in
motion. All lap-shoulder belts except driver seat have special seat belt retractors for secure fastening
of child restraints. To fasten a child restraint, use th is seat belt: Follow child restraint instructions for
routing. Then pull shoulder belt out completely and let it retract. During the seat belt retraction a
ratcheting sound can be heard to indicate that the spec ial seat belt retractor is activated. The belt is
now locked. Push down on child restraint to take up any slack. To deactivate, release seat belt
buckle and let seat belt retract completely. The seat belt can again be used in the usual manner.

Warning !
Never release the seat belt buckle while vehicle is in motion, since the special seat belt
retractor will be deactivated.

Important !
The use of infant or child restraints is required by law in all 50 states and all Canadian provinces.
Infants and small children should be seated in an approp riate infant or child restraint system properly
secured by a lap-shoulder belt, and that complies with U.S. Federal Motor Vehicle Safety Standard
213 and Canadian Motor Vehicle Safety Standard 213. A statement by the child restraint
manufacturer of compliance with this standard ca n be found on the instruction label on the restraint
and in the instruction manual provided with the re straint. When using any infant or child restraint
system, be sure to carefully read and follow all manu facturer's instructions for installation and use.
Please read and observe warning labels affixed to inside of vehicle.


Children 12 years old and under must never ride in the front seat, except in a Mercedes-Benz
authorized BabySmart™ compatible child seat, which operates with the BabySmart™ 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.
According to accident statistics, children are safer when properly restrained in the rear
seating positions than in the front seating positions. Infants and small children must ride in
back seats and be seated in an infant or child restraint system, which is properly secured
with the vehicle's seat belt, fully in accordan ce with the seat manufacturer's instructions.
Infants and small children should never share a seat belt with another occupant. During an
accident, they could be crushed between the occupant and seat belt. Children too big for
child restraint systems must ride in back seats using regular seat belts. Position shoulder
belt across chest and shoulder, not face or neck. A booster seat is necessary to achieve
proper belt positioning for children from 41 Ibs. to the point where a lap/shoulder belt fits
properly without one.
When the child restraint is not in use, remove it from the car or secure it with the seat belt to
prevent the child restraint from becoming a projectile in the event of an accident.

U.S.A. Models only:
Since 1986 all U.S. child restraints comply with U. S. regulations without the use of a tether strap.
Canada Models only: This vehicle is provided with tether anchorages for a top tether strap. Consult
your authorized Mercedes-Benz dealer for installa tion of these anchorages. In compliance with
Canadian Motor Vehicle Safety Standard 210.1, ch ild restraint tether anchorage hardware is
attached to the tool kit located in the trunk.

Enlarged Cargo (Option)




1. Locking handle, left backrest
2. Locking handle, right backrest



3. Indicator, right backrest lock,
visible in unlocked position
4. Indicator, left backrest lock,
not visible in locked position



Split Folding Rear Seat Backrest

On vehicles with optional split folding rear seat backrest you can fold down the two sections
separately to enlarge the cargo area.

Fold down:
Pull locking handle and fold backrest forward.
Set up:
Pull backrest up until it locks in its upright position. Check for secure locking by pushing and pulling on the backrest.

Warning !
Always lock backrest in its upright position when rear seat bench is occupied by passengers, cargo is being
carried in the trunk, or the extended cargo area is not in use.


Note:
To prevent unauthorized persons from access to the trunk, always lock backrest in its upright position.

Loading instructions
(Vehicles with enlarged cargo area)

The total load weight including vehicle occupants and luggage/ cargo should not exceed the vehicle capacity
weight indicated on the certification tag which can be found on the left door pillar. The handling characteristics
of a fully loaded vehicle depend greatly on the load distribution. It is therefore recommended to load the vehicle
according to the illustrations shown, with the heaviest items being placed towards the front of the vehicle.
Always place items being carried against front or rear seat backrests, and fasten them as securely as possible.
The heaviest portion of the cargo should always be kept as low as possible since it influences the handling
characteristics of the vehicle.

Notes:
The trunk is the preferred place to carry objects. The enlarged cargo area should only be used for items which
do not fit in the trunk alone.

Warning !
In an accident, during hard braking or sudden maneuvers, loose items will be thrown around inside the
vehicle, and can cause injury to vehicle occupants unless the items are securely fastened in the vehicle.
To help avoid personal injury during a collision or sudden maneuver, exercise care when stowing things.
Put luggage or cargo in the trunk if possible. Do not pile luggage or cargo higher than the seat backs.
Do not place anything on the shelf below the rear window. Never drive vehicle with trunk lid open while
pass-through is not closed and seat backrest sections not locked in its upright position. Deadly carbon
monoxide (CO) gases may enter vehicle interior resulting in unconsciousness and death.

Cargo Tie-Down Rings
(Vehicles with enlarged cargo area)

1. Ring
Carefully secure cargo by applying even load on all four rings
with rope of sufficient strength to hold down the cargo.

Shelf below Rear Window

Warning!
The shelf below the rear window should not be used to carry objects. This will avoid such
objects from being thrown about and injuring vehicle occupants during an accident or
sudden maneuver. The trunk is the preferred place to carry objects.

Steering Lock

0 - The electronic key can be withdrawn in this position only. The steering is locked with the electronic key removed
from the steering lock. The electronic key an be removed only with the selector lever in position "P" and the foot off
the brake pedal. After removing the electronic key or with the electronic key in steering lock position 0, the
selector lever is locked in position "P".
1 - Steering is unlocked. (If necessary, move steering wheel slightly to allow the electronic key to be turned clockwise
to position 1.) Most electrical consumers can be operated. For detailed information see respective subjects.
2 - Driving position.
3 - Starting position.

Refer to Index for Starting and turning off the engine.


Warning !
When leaving the vehicle always remove the electronic key from the steering lock, and lock the vehicle.
Do not leave children unattended in the vehicle, or with access to an unlocked vehicle.
Unsupervised use of vehicle equipment may cause serious personal injury.


Important !
If the electronic key is left in the steering lock position 0 for an extended period of time, it can no longer be turned
in the lock. In this case, remove electronic key from steering lock and reinsert.

Notes:
A warning sounds when the driver's door is opened with the electronic key in steering lock position 1 or 0. With the
engine at idle speed, the charging rate of the alternator (output) is limited. It is therefore recommended to turn off
unnecessary electrical consumers while driving in stop-and-go traffic. This precaution helps to avoid draining of the
battery. Unnecessary strain on the battery and charging system may be minimized by turning off the following power
consumers, for example: Heated seats, rear window defroster. In addition, the automatic climate air volume control
should be set to the lowest position. The steering lock can only be unlocked with the vehicle battery properly
connected.

Caution !
To prevent accelerated battery discharge and a possible dead battery, always remove the electronic key from the
steering lock. Do not leave the electronic key in steering lock position 0.