TPMS (Tyre Pressure Monitoring System) is an electronic system that provides the driver with real time data of the pressure of each individual tyre via the cars onboard computer systems warning the driver in the event of under-inflation.
Since 2014, all vehicles are manufactured with an integrated TPMS system (see direct v indirect) with a legal requirement that if a vehicle is fitted with TPMS technology it must be operative and maintained.