the car uses the wheel speed sensors to determine if the tire pressures are different or if one has a drastic change in revolutions ( like a tire that is loosing air)

the Tire Pressure system works, as i have the same system on the Bonneville as the GP and it has alerted me of a tire loosing air (big screw thru the tread) before i felt anything was wrong or had the tire completely flat. I was able to make it to a safe place and put a tire plug in the tread