Why is the tire pressure not displayed after replacing the spare tire?
1 Answers
After replacing the spare tire, the tire pressure is not displayed because the spare tire does not contain a tire pressure sensor. There are three common methods of tire pressure monitoring: Direct Tire Pressure Monitoring: Direct tire pressure monitoring devices use pressure sensors installed in each tire to directly measure tire pressure. Wireless transmitters send pressure information from inside the tire to a central receiver module, which then displays the tire pressure data for each tire. The system automatically alerts when the tire pressure is too low or there is a leak. Indirect Tire Pressure Monitoring: When the pressure in a tire decreases, the vehicle's weight causes the rolling radius of that wheel to become smaller, resulting in a faster rotation speed compared to other wheels. By comparing the differences in rotation speed between tires, the system monitors tire pressure. Indirect tire pressure warning systems essentially rely on calculating the rolling radius of the tires to monitor pressure. Introduction to Tire Pressure Monitoring System (TPMS): This system combines the advantages of the two aforementioned systems. It is equipped with direct sensors in two diagonally opposite tires and includes a four-wheel indirect system. Compared to using only a direct system, this hybrid system reduces costs and overcomes the limitation of indirect systems, which cannot detect when multiple tires simultaneously have low pressure. However, it still cannot provide real-time pressure data for all four tires like a direct system.
