Inflatable Restraint Front End Sensor (EFS), Buick

The front end sensors (EFS), also known as the inflatable restraint electronic frontal sensor, is equipped on vehicles to supplement the SIR system performance. Each EFS is an electronic sensor and is not part of the deployment loops, but instead provides an input to the inflatable restraint sensing and diagnostic module (SDM). Each EFS can assist in determining the severity of some frontal collisions. The SDM contains a microprocessor which performs calculations using the measured accelerations and compares these calculations to a value stored in memory. When the generated calculations exceed the stored value, the SDM will cause current to flow through the frontal deployment loops, deploying the frontal air bags.