TPMS went on the day after I bought the vehicle

[NYC_Medic]

So I have an iTouring mazda3 that I bought yesterday and while driving today I noticed the TPMS light went on. It wasn't blinking it was just on. I pulled over and all four tires looked the exact same with plenty of air. My buddy(who is not mazda owner) told me the weather can change the tire pressure. It was 18 degrees outside but the light went on after I've been driving for almost an hour. Anyone else have this problem?

 

[CXVille]

Did you actually check the tire pressure? Many decades ago, when radials first came out, there was a big push about the fact that your couldn't *see* the difference 10 psi makes in a tire. That is still true today. Did you reset the TPMS?

The system on these cars is not that advanced, as I believe it is an ABS sensor based system which checks relative rotational speeds of the tires. What you described is exactly what would happen with a slow leak. It also can happen with changing tire temps and pressures. Make sure the pressures are all the same, and reset the TPMS according to the book.

 

[GasSaver14]

My tires came with nitrogen valve stem caps that had the N2 on top. If you have Nitrogen in your tires it should not change enoungh to trip the TPMS.

They could just be filling them with air and advertising nitrogem filled tires. Who knows but my TPMS sensor has not triped.

 

[GasSaver14]

After A little research I found out that Nitrogen makes little difference. I'm going to fill mine with air as they begin to leak. Works better for NASCAR than consumer car.