I bought car new & it developed issue @ 3 1/2 yrs. I also have the Subaru extended warranty.car has only been serviced by Subaru, including tire changes. 10/11 @ 38,000 noticed front & rear passenger tires were losing air. I have TPMS w/ metal valve stems. Brought car to dealer, they found nothing wrong. I have two sets of tires so I brought car in 11/11 to put on snows. Monitored tire pressure every few days and was still losing air. 10/12, I spray soap/water mixture on tires, bubbles form at the base of the tire valve. Four valves should not be failing prematurely. Over time, the both drivers side tires developed slow leaks as well. 10/12, I called Subaru warranty department & explain that I'm losing air from the valve. I ask if TPMS failure is covered & was told it is. 11/12 45,044 bring car in to put on snows. Tell dealer that all four valves are leaking. I'm told it may be corrosion & that's not covered under warranty. I explain that for all four to be leaking is premature. Tech confirms that three are leaking & replaces them. Dealer states that there isn't a warranty code for air leaking but will find a way to make sure it's covered. The TPMS unit is one piece so if the valve stem fails or a rubber sealing gasket the whole unit needs to be replaced. I don't know if this is a design flaw and corrosion can cause the metal valve stems to fail prematurely. I check my tire pressure every two weeks by rule & don't wait till the TPMS light comes on.

- East Providence, RI, USA