TPMS prob
 

Alright so recently I bought new wheels and tires.

Ok lemme explain.

I have a stock X, I then upgraded to new tires. some 31"
I had no problem with the TPMS.

Later i upgraded to 35" tires and new wheels.
The old spare was replaced with one of the old 31" tires and wheels.

The first two days were just fine. Next thing you know the TPMS is coming on. How do i figure out whether it is an actual problem or if one of the TPMS are off or missing or what? Why would it not go off at first and not it does?