[mikecx3]

I havent had a new car for a while and I like to check my tire pressures, I realize the sensors monitor the tires but the valve caps have green things on them, does that mean pressire is good, do they change to say red if theres a problem??

 

[Snoogie]

You are going to have to be more specific here with pics as to what you are talking about.

 

[anchorman]

It just means that the tires are inflated with nitrogen which is very stable due to changes in temperature.