A TPMS sensor is a component of the Tire Pressure Monitoring System (TPMS) that has been standard on vehicles produced since 2008. TPMS uses sensors located inside each wheel to continuously monitor the pressure in the tires. Data from the sensors is sent wirelessly to a computer control module. When the pressure falls below a designated threshold, the computer triggers a warning that appears on the dashboard display.
The sensors are mounted on the inside end of the valve stems where they measure the air pressure of each tire. The TPMS on some vehicles provides a constant visual display of the pressure in all of the tires, while the system on other vehicles only gives warning if they are low.