The crash sensor is a clever electronic sensor which detects when the vehicle has crashed and which area is damaged. This information is used to decide if and when the vehicle restraint and safety systems, such as seatbelt tensioners and airbags, are activated.
There are several different types of crash sensor which monitor and measure factors such as sudden deceleration and the speed of the wheels and brake pressure upon impact, and this vital information is sent to the airbag control unit ECU, which is the control centre of the airbag and automatic vehicle restraint system. Situated towards the front of the vehicle in the frontal impact/crush zone, the intelligent crash sensor can detect what type of collision has occurred, the angle at which the vehicle collided and how extreme the impact is. The airbag control unit ECU will determine if it needs to implement the activation of airbags as well as deciding if functions such as automatic seat belt and door lock are put into place. This all happens within a matter of milliseconds of impact.
Essentially, the crash sensor works with the airbag system and the ECU to ensure the vehicle's crucial safety devices function effectively and are deployed at the point they are needed.
The airbag control unit ECU will regularly carry out routine diagnostic checks of the crash sensors and, if it picks up a fault, the air bag system warning light will illuminate on the dashboard. Once the airbag system warning light illuminates the system usually becomes inactive, which means that, if you have a crash, safety systems such as the airbags won't work. It is therefore vital to address the problem as soon as possible. If the crash sensor has suffered damage in a crash, or there's a fault with the electrical contacts in the sensor it will need to be replaced. Fitting the crash sensor will ensure this part will be compatible with the make and model of your vehicle.