Quote:
Originally Posted by pdhart
My understanding was that the tire pressure sensor actually measures the rotational speed of each tire and detects a flat using that, rather than a sensor in each tyre.
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I believe that is the older style system. The older GM vehicles used ABS wheel speed to determine a lower tire pressure; known as the "indirect" pressure system.
Newer styles are called "direct" pressure and have pressure ports in the sensor to read actual air pressure. There is an oscillator in the sensor, so that it only transmits information when it senses tire rotation, which conserves TPS battery life. They operate at 315mhz up til 2010, and at 433mhz from 2010-up.
https://en.wikipedia.org/wiki/Tire-p...itoring_system
https://www.ateq-tpms.com/en-us/arti...-bmw-5-series/