the way it works is tire rotation. there is no pressure sensor in the tire so it won't show pressure. a sensor in the tire is how the 1st gen TPS worked and after a few years you had to pay $500 to replace them because the batteries died.
in this one, it measures the rotation speed using the ABS sensor. when you fill it to appropriate pressure and then tell the computer it is ready to be calibrated, it can then tell when the pressure is lower because of faster rotation vs the other tires on the same side of the car. it will alert a low condition if it changes but not drastically, it will say to stop immediately if a drastic difference is detected meaning the tire has a big hole in it.
in this one, it measures the rotation speed using the ABS sensor. when you fill it to appropriate pressure and then tell the computer it is ready to be calibrated, it can then tell when the pressure is lower because of faster rotation vs the other tires on the same side of the car. it will alert a low condition if it changes but not drastically, it will say to stop immediately if a drastic difference is detected meaning the tire has a big hole in it.