I have had 2 tire pressure monitoring valves break into 2 parts each in the past 4 months. The latest was when I was driving today on city streets. The tire pressure alarm went off so I stopped the car to check the tires. When I touched one of the valves it just came apart in my hand and I was holding part of the valve, the rest of it was still in the tire. The tire then completely deflated in about 2 seconds. This could be extremely hazardous. If you lost all tire pressure in a few seconds at 65 mph you could easily lose control of the car and get in an accident. I no longer trust the 2 valves that have yet to break so I am going to be proactive and replace them before they do break at an inopportune time. I see a lot of other complaints about the same problem on the internet. I included a picture of the piece of the valve that broke off into my hand.

- Cleveland Heights, OH, USA

The tire pressure sensor illuminated and I checked to see if the tire was flat. It was not. I drove to a filling station to top off the pressure and as I was driving away from the air pump the valve stem to the rear driver side tire broke and the tire deflated instantly. The valve stem was corroded. Apparently it was initially cracked slightly causing the tire to first lose air slowly. Then, upon manipulation from the pump fitting, the stem was further damaged causing the stem to break off. I did have this happen once before. The explanation from a service station was the same. In this model the valve stem and pressure sensor is a single assembly so when the tire is changed the valve stem is not changed even if it is old and showing signs of aging. Otherwise the cost of replacing a tire would be nearly doubled. The sensor itself will last much longer than its valve stem. Consequently, the stems do eventually corrode and break off at inconvenient, possibly dangerous, times. The service stations say this is common for this vintage of Mazda. The service rep said mine was the second they repaired on the very same day! as I said, this happened once before when a stem broke off as I was backing out of my home parking spot. A couple of days before the this reported event, I took a long road trip and a sudden deflation like this could have happened at highway speed. It would have been tragic! I have checked on-line and have found many identical complaints. If it has not been reported to NHTSA before now, I am quite amazed.

- Chadds Ford, PA, USA

Went to inflate tires, valve stem broke and tire went completely flat. I was lucky that this happened when the car wasn't moving - I have read about the valves failing at highway speed, when it could have caused an accident.

- University Park, MD, USA

TPMS sensor-valve failure: I was driving to work going about 40 mph when TPMS light went on. I could not pull off immediately because of road conditions. Shortly after that I could hear the sound of a very flat tire. When I managed to pull off and check the tires, one was completely flat. Tire was too damaged to re-inflate. The relatively new tire and the TPMS sensor had to be replaced.

- Charlestown, RI, USA

TPMS sensor-valve slow leak: Four new tires (pirelli P6 four seasons) installed at Mazda dealer on Jan 2011. The original TPMS sensor-valves where used on the new tires. After that the TPMS warning light would go on every couple of weeks. I would check the pressure in all the tires using a digital gauge which showed slightly low pressure (high 20?S psi) in one tire, the same tire each time. I would inflate the tire to the correct pressure. One reason I am reporting this is that there is a well-documented history of TPMS sensor valves breaking easily when putting air in the tire. The more one has to inflate the tires the more likely the TPMS sensor-values will break.

- Charlestown, RI, USA