Since November 1, 2014, all new European cars (Category M1) must have a Tire Pressure Monitoring System (TPMS) installed. The tire pressure monitoring system is based on different concepts and sensors. There are basically two main types of tire pressure monitoring systems:
Direct tire pressure monitoring system - the air pressure sensor is integrated with the valve, either attached to the rim or installed inside the tire.
Indirect tire pressure monitoring system - no air pressure sensor installed on the tire / rim. The tire pressure difference is measured "indirectly" by the change in the rolling circumference of the tire.
Automakers can choose either direct or indirect tire pressure monitoring systems.
The matching and maintenance of the tire pressure monitoring system is carried out by the tire specialist.