Tire Pressure Monitoring System. By law all vehicles produced after September 2007 must have a tire pressure monitoring system or TPMS. This system through a series of sensors activates a warning either through a light on the dash or rolling sign generally on the odometer letting the driver know if a tire is low on air pressure and which one it is. The sensors for this system are generally in each tire and wheel assembly. Most of the sensors are incorporated into the valve stem assembly of the tire. Special care needs to be taken if the tire is taken off the wheel not to disturb or destroy the sensor. When rotating tires on a vehicle equipped with TPMS the computer module must be reprogrammed after tire rotation so the computer can identify where each sensor has been relocated. All of our tire experts at Galaxy Auto & Tire have been properly trained to handle the tire and wheel assemblies and re-program the system to function correctly after service.