RAY: We have in our shop a device which is called the scan tool, and ours is made by Snap On, and it's a wonderful thing, and I suppose most shops have such a device. Anyway, you take the scan tool and you connect it to usually a plug under the dashboard or under the hood and it extracts valuable information from the car's computer. And once we get that information, then we can accurately misdiagnose a whole range of problems.

TOM: Right.

RAY: Recently we got a new piece of software for our scan tool, and one of the guys plugged it in, and he starts scrolling through the data and looking for readings that are out of the normal range. For example, it might say that the engine operating temperature is minus 40 degrees and that might give you an idea that something is wrong with the coolant temp sensor. Or you forgot to pay the heating bill at the garage or something like that. Anyway, as this fellow is scrolling down looking for all this information it gives you, I was looking over his shoulder, and he comes to a thing that says, "tire pressure low, right front." And he says, "Huh?"

So I walk around to the right front and, sure enough, it looks pretty low -- it's almost flat -- and I say, "Geez, it's right." And he says, "How does this thing know? There's no air pressure monitor in this car." And that's the question. How did the scanner know?