Carrier/rack problems of the 2009 Mazda MAZDA3

Two of the tpms (tire pressure monitoring s___?) sensors were cracked and replaced at a discounted cost to me of $325. The car is only 4 years old with under 52,000 miles and two of them crack at the same time (!). The Mazda dealer said that they get a number of these problems and that they think it is due to poor quality metal being used. This is clearly a safety issue since they crack too early in the life of the vehicle and the customer has no way of determining this or even knowing how or where to look. I am now very nervous about the remaining two.

Three out of four tire pressure monitors have failed causing tire deflation. The first two times this was discovered in my driveway. Upon trying to re-inflate the low tires I found that the tire pressure monitors just fell away into the interior of the tire. My tire dealer was able to reinstall the monitors(only to have them fail again later) my complaint stems from the incident (after I have stewed about it for a while) that happened on 6-26-2013. My wife,with daughter, had a blowout on interstate 75 at rush hour in a driving rain storm. Of course it was a harrowing experience getting the vehicle to the shoulder. Luckily a less experienced driver was not at the wheel. When I arrived to change the tire I decided to try and re-inflate it first to try and get to a safer location. Once again the tire pressure monitor fell to the interior of the tire!!! my tire dealer (tire discounters walton ky) told me that the threads on the stem that holds the monitor to the wheel corrodes and eventually cracks the nut holding the monitor. What a piece of junk. I still have the old monitors and indeed the corrosion looks like something that comes from a dissimilar metal on metal contact. This is a major safety concern in my opinion and I should have complained as soon as I could but I really think that nothing will come of it. I almost paid for new monitors(decided to just replace with plain stems on my own as I do not trust ,nor do I want to finance Mazda any further), I lost a tire due to the highway incident and I found out that this is no surprise to the tire store.

The tire pressure monitoring sensor mounted in the rim failed and the tire lossed air pressure while traveling on an interstate highway until it was flat and the spare tire needed to be mounted. The flat tire was later taken to a tire service dealer who determined that the flat was caused by corrosion of the threaded aluminum stem on the tpms causing the plastic retaining nut to crack and fall off resulting in a leak around the rim and stem. The corrosion was so severe that the tpms could not be used, and a rubber valve stem inserted. The corrosion was not obvious as the owner of the vehicle routinely inflates the tires, the nut concealed the corrosion. Corrosion this severe was not anticipated at 25k miles of driving, the tires were not yet worn to the point of requiring replacement. The design and application of the tpms used for this vehicle is dangerous as rapid deflation of the tire could have resulted, the outward appearance of the valve stem does not provide any indication of pending catastrophic failure, the exposure of the tire and valve stem to DE-icing materials in the northeastern USA is a normal environmental exposure that would warrant significantly better corrosion protection than the oem tpms that is installed provides. A full recall and replacement of the tpms's installed in this make, model and year needs to be made. This type of failure has never been experienced by the owner when rubber valve stems were used in the past, it is unfortunate that a new safety device - tpms - presents a higher risk for catastrophic rapid deflation of a tire at highway speeds than would ever be expected.