question about tire monitoring system

[DirtDog]

so when i went to get my tires replaced they said that they may have to order a cheap tire monitoring thing that goes on the valve stem for the tire because they aren't reusable. but when they took the tire off of the rim they said that it does not have any type of device in the rim like most GM's did. so if that's the case (keep in mind i went and looked myself) how does the system monitor the tire pressure? I know it works cause it's told me my tires were low before?

http://www.carparts.com/details/GMC/...FQWnnQodcUAAUg

that is what they thought that the tire would use to monitor the tire pressure like most GM's do...but it did not have one in there? this is more for my curiosity of wanting to know how the heck it works.

[Schmidty]

its a TPMS (Tire pressure monitoring system) have one in my 07 GXP. info shows up in DIC and tells you what your tire pressure is.
Tire Pressure Monitoring System (TPMS) - Discount Tire

[DirtDog]

yea i know thats what it is but when they took my tire off the rim it doesnt have it in there but the car still knows when the pressure in one is low? my question is if the tires dont have them how does my dic know?

[DirtDog]

Your vehicle may have the Tire Inflation Monitor
System (TIMS). The system is designed to alert the
driver when there is a large air pressure change in
one tire, while the vehicle is being driven. TIMS detects
differences in tire rotation speeds that are caused by
changes in tire pressure. The system can alert you
about a low tire but it does not replace normal
tire maintenance. See Tires on page 5-60. The TIMS
learns the pressure at each tire throughout the operating
speed range of the vehicle. The system normally
takes between 45 and 90 minutes of driving to learn the
tire pressures. This time may be longer depending on
individual driving habits. Learning need not be
accumulated during a single trip. Once learned, the
system will remember the tire pressures until the
system is reset.

finally found the answer. now i wanna figure out how it actually monitors this...wanting to know how things works

[Fivefingerdeathpunch]

Your GXP will have these style sensors. They have a chip in them that talks with the car to tell you its pressure.

That link you posted is of just a valve stem for a newer style TPMS sensor, like 09+.

[DirtDog]

Where are those sensors located?

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[Fivefingerdeathpunch]

The sensor is your valve stem, its a whole unit.

[DirtDog]

OK so does it have to be replaced when I swap rims? Cause we have my tire off at the shop right now and I don't remember seeing anything like that in there...

Edit: I'm just curious for when my correct size rims get back in

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[Fivefingerdeathpunch]

You just have to swap it over to the new rim, they make "repair kits" that come with a new gasket and plastic nut.

If you valve stems look like this on the rims on your car now, you have sensors. To my knowledge ALL GXP had TPMS like this, or any Grand Prix 07+.

[Rob97gtp]

The old style tpms use abs system/sensors to determine if a tire is low apposed to others that's it. you reset it in the dic or drive it will go away as long as all are matched.

[DirtDog]

I'll take a pic but if I remember correctly it looked exactly like a normal tire stem...that's what why I'm curious as to how it works. The guy doing the rim/tire swap for me said that it looked like any old valve stem

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[Bio248]

put regular valve stems in it and deal with the goofy light.

those things are expensive. ain't nobody got time for that.

[Fivefingerdeathpunch]

That style are cheap actually. I deal with these everyday, gets old lol.

[Rob97gtp]

If it has regular stems and u had no light on before its the abs style system that don't require sensors in the wheel.