[quote=hinrichsscott;6076106]
How long do they last?
The expected life is 5-8 years. I have replaced some that have been less and we can expect some to last longer. I would probably guess that it has to do with how long you drive (not necessarily how for) since the sensors are more active while the vehicle is in motion and less active when the vehicle is stopped for an extended period.
Do they run off a battery? (I would think they'd have to).
-Yes
Can you replace the battery when it dies or do you have to buy a new sensor?
-I am not aware of any that the battery is serviceable.
When getting new tires do you have to replace the sensor?
-No
Can you replace the valve stem seperately from the TPMS sensor?
-Some you can some you cant
Should you still replace the stem when getting new tires?
-There are service kits that contain all the seals and parts needed to "reseal" the sensor to the wheel. The manufacturers may or may not recommend these with tire replacement.
Are the sensors specific to each position on the car - if I rotate the tires will I have a problem?
-your owners manual will explain that
If I eventually buy aftermarket sensors will they work?
-If they are made for your vehicle. We get aftermarket sensors when available and they have worked just fine for there applications
What would I have to look for in aftermarket sensors (are there different frequencies?)
-They should be listed as compatible with your vehicle.
Are all 08 Caravan sensors the same?
-Manufacturers may have different sensors for different wheels (steel wheels may require a different stem angle than an aluminum wheel)
Will I have to "reprogram" the sensors or the car if I buy new sensors?
-I don't know for sure on your specific vehicle
Can a shadetree mechanic reprogram the TPMS or does this require the dealer?
-I don't know for sure on your specific vehicle