What is a Tire Pressure Monitoring System?
A tire pressure monitoring system or TPMS is an electronic system for monitoring the air pressure in a vehicle tire and automatically transmitting a warning to the driver in the event of an under or over inflated tire. These systems have been legislated to be progressively installed on all new passenger carrying US vehicles and a similar move is taking place worldwide.
The majority of systems use Direct tire sensors which transmit real time tire pressure information to the driver of the vehicle either via either a dashboard display or a warning light. The sensors are physical pressure transducers which are attached to the back of the valve stem or are in a form which is banded to the wheel. The sensors are manufactured by International companies such as Schrader, Siemens, TRW, Pacific, Lear and others. There is no common technical standard for the sensors and the OE's and suppliers have generated a multitude of sensor designs.
The sensors also transmit data such as their unique sensor ID, temperature and pressure, battery life and other diagnostic information. This data is sent to the Engine Control Unit (ECU) or specific receiver on the vehicle. Those vehicles which have graphical displays of the TPMS positions can then show on which wheel there is a problem.