Direct TPMS methods use pressure sensors to measure pressure in each of the four tires. Then these sensors transmit the pressure data via a wireless RF transmitter to a central receiver. The receiver communicates to a display that informs the driver which tire is underinflated. The tag in each wheel is designed to send a warning signal when a tire's pressure drops below its specified safety level. Tire-mounted pressure sensor is shown in Figure 1. Under-inflation has been cited as a cause of tire failures such as tread separation or tire blowouts. It is also responsible for shortening tire life and reducing fuel economy.
Indirect systems employ wheel speed sensors on a vehicle's anti-lock brake (ABS) system to track each tire's rotation. The premise is that under-inflated tires have a smaller radius, resulting in a higher rotational speed compared with a fully inflated tire. The sensor is supposed to detect the faster rotation, and the system alerts the driver. In practice, this change in radius is small, making indirect measurement less reliable than direct pressure measurement.
Prevents the consequences of low tire pressure through early detection:
How to keep your tires properly inflated:
1: Check tire pressure at least once a month and before going on long trips. Since temperature affects tire pressure, it is best to check tires when they are cold, i.e. haven't been driven on for at least three hours.
2: Fill your tires with the pressure recommended on the tire label, located on the drivers door frame, sill or edge.
3: If you have any questions about your tires or maintenance, check your owners manual or consult your dealer.