Another expansion option for movement sensors is to use a silicon mass. If force is applied, the silicon mass in the sensor moves. Due to the way in which the mass is suspended in the sensor, this changes the electrical capacitance, which serves as information for the control unit.
Thanks to the speed at which they can record information, these sensors are used to supply information to the control unit as quickly as possible in the event of a side impact.
Pressure sensors are also used. They are installed in the doors and respond to changes in pressure inside the doors in the event of an accident. When working on vehicles that use these pressure sensors, it is essential to properly refit the door sealing foils following their removal. If the door sealing foil has been incorrectly fitted and this results in pressure loss during an accident, the function of the pressure sensors may be impaired.
When mounting the crash sensors, always observe the installation direction, which is indicated by an arrow on the sensor. The deployment threshold is an acceleration of approx. 3 – 5 g. For safety reasons, in order to avoid the airbag(s) being deployed unintentionally, two sensors that operate independently from one another must always send the information to deploy the airbag(s). The safing sensor is used as a safety sensor.