The TPMS sensors on Chrylsers and GM would break because of corrosion built up between the cap and the stem itself. The cap sticks to the stem and then when you apply a ton of force to it, it cracks the whole stem. This is more common in the northern states because of the road salt.
We saw it all the time and if we broke a stem on the sensor we would replace it for free. Never ever put aftermarket valve stem caps on the sensors. Different metals generally dont like touching each other and cause corrosion due to their different electrical charge.
The first thing that I did on my nissan was to put some oil on the threads of my valvestems to prevent corrosion or salt from getting in there.
As far as the reason of TPMS becoming a requirement, it wasn't actually Firestones fault. The tires were not faulty, Ford were idiots because their Explorers were getting very very poor ratings in the rollover category. Instead of doing something intelligent, Ford simply lowered the tire pressure to create a softer tire which allowed the Explorers to be able to roll more and improve the rollover rating. However, when these things were loaded down in the summer with weight, families, boats, etc, the sidewall would reach an extreme temperature and blow out. Ford was at fault - not Firestone.
Any tire that is inderinflated in high temps, with a heavy load, or traveling fast will cause the tire to explode.
A blinking TPMS light is indicating a malfunction or dead sensor. A lit up sensor is indiciating incorrect tire pressure.
