While getting an oil change my tire's valve stem broke off as a technician was checking the pressure/refilling the the tire. The tire quickly lost pressure. A tech quickly refilled and capped off my tire. This helped the tire keep enough pressure so I could limp over to a nearby tire place. I had just had the tire replaced and the valve serviced 2 months prior. The tire place told me that they hadn't seen any problems at the time they changed my tire. They had said that they have seen this type of breakage when a tire had a cap stuck due to long wear and not being taken off, but as they said mine was just removed when it was serviced. I feel that the tire pressure monitoring sensor system is a horrible design. The treads on the valves housing (where it snapped) needed to be constructed of a stronger material and the valve stem designed should be only a component of the PMS not one continuous part. I would have been in real trouble if the treads failed while driving.