Do the TPMS units have a removable stem/core that can be replaced without removing the entire TPMS sensor (by removing the tire from the wheel rim). One dealer told me that the stem can get dirty or stuck or break and can be easily replaced cheaply (right !) One tire has responded when trying to change the tire pressure, by suddenly releasing air directly from the opening. If the cap can be screwed back on the air release stops. 20 minutes earlier, the pressure was checked on all the tires and they were holding just fine.....then I decided to change the pressure on all the tires (they were just put on recently as new Michelin SS)

 

Yes,
Fix a Leaking Tire Valve Stem | The Family Handyman

Hopefully the only issue is the valve core.

 

Yes but make sure you use ONLY a nickel plated valve stem core.

If you fit new tires ALWAYS fit new TPMS as the batteries in those valve stems last only about five years.

Also, unless the TPMS valve stems are correctly installed at the correct torque in inch pounds they will leak or fail.

 

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Don't know where to start......the problem is solved, thanks to Big O Tires. I used to get my tires from Tire Rack (still do) and send them to Big O. Well, not this time. However, after spending most of the afternoon calling three dealers and the outfit that installed my new tires, I finally at the end called Big O, and they understood my problem and in 5 minutes time installed a new stem core and set it at the required torque. I have driven over 300 miles on the new tires. The dealer tried to blame the new tire installer and the installer would not take the blame right up front but that is OK since on reflection, I may have caused the problem when I was inflating the tires to a new pressure. The phone calls went back and forth and I learned a lot about the price range or variance from each source.....what a joke ! BTW, the guy at Big O (Brandon) didn't charge me a dime. On a side note.....I need a 30K service and one (local) dealer wanted $480 even though they had just done a thorough check-up at a free clinic they offered and said everything was perfect (without an oil and filter change) while the dealer I bought the car from wanted $220 and even though he is 40 miles away....he gets my business.