I just bought this 06, a CPO car. The tire valves look like the old rubber ones, but many of the cars I see have steel or aluminum rigid valve stems. The dealer said I have a different style operated by part of the ABS system which measures tire circumference. If circumference goes down, its losing air , and will then warn me in the cockpit. The sensors are not in the wheels themselves.Does this make sense to any of you? Do other 06 models operate like mine????