Hi, the guy at Discount Tire said he could not get ANY of the sensors to read, so to me, that would mean that they read dashes or 0s. He suggested replacing all of the sensors, but I was highly skeptical since what are the odds that all 4 sensors died at the same time? What lead to my having them read was when my TPMS light on the dash came on -- after determining that all my tires had good air pressure, took the car to Discount Tire to get a reading on which tire or sensor was the issue, and they said they could not get a reading on any of them. I've had the same tires on the car for a couple of years so nothing was done like putting in the wrong sensors or tampering of any kind. I understand that sensors eventually need to be replaced as the battery dies or the sensor just goes bad -- but how can it be possible for ALL 4 of them to die at the same time? Which is why it seems like something else is going on. I don't know how they test the sensors other than it's with a handheld unit, but I don't know if they are reading at each tire, or at some central "brain" (receiver). If they trying to get a reading at the receiver, then maybe that, being common to each sensor, could be the issue. But I just don't know, and all Discount Tire had to say about it is that "we're not mechanics" yet they would be happy to replace all 4 sensors without an actual diagnosis. :frown2: