ACDelco GM Original Equipment Tire Pressure Sensor is a battery powered sensor located in the tire that monitor the vehicles tire pressure, and are GM-recommended replacements for your vehicles original components. They warn the driver when pressure falls more than 25% below the manufacturers recommendations (normally through a slow pressure loss). The tire pressure sensor is connected with the valve stem, and by way of Radio Frequency (RF) technology, sends pressure updates to the vehicles on-board computer. Tire pressure is displayed on the vehicles Driver Information Center (DIC), or when low, a warning lamp might be illuminated to warn the driver. NHTSA mandated that new cars and light trucks be equipped with TPMS starting in 2008. These original equipment tire pressure sensors have been manufactured to fit your specific GM vehicle, providing the same performance, durability, and service life you expect from General Motors.