Activating the safety system

Comprehensive tests are used to define triggering thresholds for all possible types of accident. This results in different trigger thresholds for activation of the various restraint systems (such as airbags, belt tensioners, Crash Active head restraints).

The restraint systems are triggered only when 2 independent sensors detect the corresponding threshold. For example, a rear-end collision is detected by the longitudinal acceleration sensor in the airbag sensor in the driver's side B-pillar and by the longitudinal acceleration sensor in the crash safety module or MRS control unit. The crash safety module or MRS control unit calculates the direction of the impact and the accident severity from the data sent by the sensors. Depending upon the severity of the accident, the Crash Active head restraints and/or the safety battery terminal may be triggered, and the electric fuel pump may be deactivated.