GM Genuine Parts Tire Pressure Monitoring Sensors (TPMS) are designed, engineered, and tested to rigorous standards, and are backed by General Motors. These sensors are battery powered sensors located in the tire that monitor the vehicle's tire pressure and warn the driver when pressure falls more than 25% below the manufacturer's recommendations (normally through a slow pressure loss). The sensor is connected with the valve stem and, by way of Radio Frequency (RF) technology, sends pressure updates to the vehicle's on-board computer. Tire pressure is displayed on the vehicle's Driver Information Center (DIC) or, when low, a warning light may be illuminated to warn the driver. U.S. Federal Regulations require that new cars and light trucks be equipped with TPMS starting in 2008. GM Genuine Parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles. Some GM Genuine Parts may have formerly appeared as ACDelco GM Original Equipment (OE).