Since I bought my truck a few days ago the tire pressure monitoring system light is staying lit. All of the tires are at 35 psi like suggested in the manual. I thought it might be because it was cold out, but it never goes off.
As long as you're over the trigger point it shouldn't matter how cold it is. It may be a bad sensor. I had it take more than a few miles to turn off once. Any chance a tire has a leak and has lost pressure and you're just not aware?
By any chance, is one of the wheels/tires the spare, and therefore the spare has the TPMS? I know my Nismo has real wheels/tires on all 5, but only 4 have TPMS. Bought a 5th TPMS and using the method outlined on this site, now have 4 functional TPMS at all times, even doing a 5 way rotation.