Toyota Prius - Repair, Maintenance, Gotcha Surprise Costs

[oldschool]

I would believe that the sensors in the valve stems of the tires were for a tire pressure monitoring system. If you have this system you dont need to carry a spare,this saves weight hence better mileage.You will never get away from the requirement to keep your tools current enough to handle newer technology. Tire pressure monitoring systems are not new I can remember mid-90s corvetts another car with no spare. This is the only pourpose I can think of for sensors in the valve stems.