Is there a TPMS in the spare? I removed my spare to run with a little less weight, and maybe 30-50mi later the TPMS light came on - but we did also have a snowstorm, so not 100% sure.
Hopefully its just the spare that’s low. 2 days after picking up my ‘12 last October, one of the sensors died. Thankfully the dealer replaced no charge.You need to chack you spare, a bulge at the contract point of the tire sidewall is normal, especially as sidewalls get taller.
If your spare is at the correct pressure then you need to press the reset switch at the bottom of the drivers knee area on the dashboard.
If that doesn't work then you probably need a new sensor, as I have stated in the past the life expectancy of a tpms sensor is 5 to 10 years. Older sensors have even less life for several factors including battery tech and electronics.