Contents: SRS system warning light ↡ Warnings! Airbags, seat belt…↡ Warning! Be careful when working…↡
The airbag is built into the steering wheel. It is filled with air by an explosive process in 1/30 s. After 1/10 s, it begins to deflate thanks to the holes in it. The front passenger airbag with a volume of 170 l is filled by a gas generator and, if necessary, deploys only if the passenger seat is occupied. There is also a small storage compartment under the front passenger airbag.
The seat belt pretensioner system can be diagnosed.
The seat belt pretensioners are located on the roller mechanisms of the front belts. The actuator pushes up a piston, which is connected via a metal cable to the axis of the roller mechanism of the belt. Thus, the belt is stretched on the body with a force of 1200 N, preventing the belt from loosening in an accident. Airbags and belt pretensioners are activated by gas, which in Mercedes cars is formed from a solid explosive.
If the electronic device is triggered (in front of the gear lever) detects a vehicle delay identical to an impact at a speed of 15–18 km/h against a solid obstacle, current is supplied to the pyropatrons and gas is formed under the action of an explosive process. The system has an autonomous power supply from a capacitor, which supplies current to the pyropatrons of the gas generators even if the battery fails during an impact.
SRS system warning light
The system's continuous functional readiness is checked by its own monitoring system. When the ignition is switched on, the control lamp lights up for a few seconds and then should go out. If this does not happen or if it lights up while the vehicle is moving, there is a fault in the system.
Warnings! Airbags, seat belt pretensioners and DIY repairs
There are strict rules for transporting, storing airbags and organizing the workplace where they are removed and installed. The fact is that the gas generator, which, by activating the solid explosive contained in it in the event of an accident and filling the airbag in a split second, falls under the law on explosives. In this regard, even during serial installation at the production facility, only specially trained specialists are involved at the service station; airbag repair mechanics have special qualifications. Given the above, we strongly recommend that you refrain from any independent repair of the driver's or passenger's airbag. This also applies to tuning, when, for example, the steering wheel is trimmed with wood or leather. In any case, work with airbags should only be carried out at the service station.
The front seats of the Mercedes car are equipped with seat belt tensioners that are activated in the event of an accident. The pretensioners are activated by a gas generator that is activated by the supply of electricity. Self-repair of this system is prohibited. Work on installing and dismantling pretensioners must be carried out by service station specialists in compliance with strict safety requirements.
Warning! Be careful when working under the vehicle
When performing bodywork, do not use an impact screwdriver or hammer in the area of the seat belt roller mechanisms without extreme caution - the pretensioners are very sensitive to vibrations and impacts and may be triggered. Therefore, for safety reasons, before starting work from underneath the car, it is recommended to remove the pretensioner fuse and wait 5 minutes for the capacitors to discharge.
After an accident, check the system and replace the airbag and front seat belts if necessary.
When installing the system, removing the steering wheel or performing welding work, always remember: the airbag system parts must not be heated to a temperature above +100°C.
Always place the driver's airbag system components on a soft cloth and never leave them unattended.
In addition, they are sensitive to impacts. If dropped on the floor from a height of 50 cm or more, they are not suitable for further use.