Front End Discriminating Sensor
WARNING: This page is about a different car, the 2002 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
Front end discriminating sensor, also known as Electronic Frontal Sensor (EFS), contains an accelerometer which monitors vehicle acceleration and velocity changes to detect frontal impacts severe enough to warrant deployment of driver-side and passenger-side air bag modules. Front end discriminating sensors provide input signals to SDM, but are not part of deployment loop.