Inflatable Restraint Front End Sensor
WARNING: This page is about a different car, the 2004 Pontiac Sunfire and 2004 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
The front end sensor, also known as the electronic frontal sensor (EFS), is equipped on some vehicles to supplement SIR system performance. The EFS is an electro-mechanical sensor and is not part of the deployment loops, but instead provides an input to the SDM. The SDM uses the input from the EFS to assist in determining the severity of a frontal collision further supporting air bag deployment. If the SDM determines a deployment is warranted, the SDM will cause current to flow through the deployment loops deploying the frontal air bags.