Help me Understand TPMS

[kevinkay]

I am getting new tires, they tell me it will cost about $10 each tire for the "rebuild kit". Searched and found the TPMS valve cost way more than 10 bucks - whats the "rebuild kit"?? Can I do it myself down the road without re-mounting the tire?
How does the TPMS system work - I saw one diagram where the sensors wireless transfer info to a receiver, is this how our X5's work??

TPMS Rebuild Kits

[tmv]

I think it's vary, depend on year of production.
For my 06, the computer calculates the rotation between the wheels on the same axle and determines if the difference is enough to trigger the TPMS warning light on the dash.

[admranger]

We don't have a tire pressure monitoring system on the E53. As tmv states above, we have a tire diameter monitoring system. They are taking your money. The only "rebuild" needed is for your wallet.

Replace the valve stems, mount, air up, balance, install, torque, push/hold tire monitor button, drive. No rebuild step.

[kevinkay]

hay, thanks to you both.
I have an 04, 3.0

[kevinkay]

hay, thanks to you both.
I have an 04, 3.0

[TerminatorX5]

the TPMS has no additional hardware, just the ABS module comparing rotational speed of each tire to the other ones - less precise system, triggers warning at 20% relative difference and misses if all 4 tires are off equally...

the RDC system is using the radio senders in each rolling tire plus one in the spare, 4 antennas (rear right also picks up the spare tire signal), the whole thing reports to a dedicated RDC unit under the glove compartment - the system is very precise, reports 5% absolute deviation but very sensitive and gives a lot of false alarms... This system was used in E53 that were sold mostly overseas, not in the US - even though, you may find a unit or two still rolling in the US...

what is the label on the button on your center console (module A169) - does it say RDC or does it have a tire-flat symbol?

[bcredliner]

If you are not the original owner you could have an aftermarket system. You can tell if that is the case by looking at the valve stems or just asking Discount Tire to show you what they are rebuilding. I wouldn't jump to the conclusion they are trying to rip you off yet. If they are not there it could just be a mistake, humans do make mistakes.

A rebuild kit replaces the parts in the valve stem that degrade and can cause a leak. It would be SOP for any tire store to replace these parts just as they replace a normal valve stem when you replace a tire.

[kevinkay]

My car has a flat tire symbol on the button. Two tire shops over the phone asked year/make/Model And both said the exact same phrase of "corrosion" And recommended the rebuild kit. I still don't get it ....is there an antenna in the tire that can ware out?

[TerminatorX5]

your car does NOT have actual hardware in the tires or the fender/wheel wells... the only hardware piece is different version of the center switch (module A169), that has the TPMS button (some have heated seats, all have Hill Descent, trunk, some have PDC). If all "buttons" are utilized, you only have one spot left... anyways, the tire pressure readings are taken in the software/firmware of the ABS module, that all the cars are equipped with.

the corrosion that they are referring to is for the actual sender units and to be honest, i am not sure that even if you had the RDCs, they would be able to replace the stems on the senders... you do not have pressure hardware in your car and they are mistaken - not to discount some aftermarket devices that the previous owner may have installed...

[kevinkay]

OK, I got it, THANK YOU!

b.t.y, I am pretty observant and maintain my car well - but that light has alerted me to pressure/tire problems several times.