This morning, upon start-up, the Tire Pressure Sensor (TPS) came on for the first time ever. I immediately got out and checked the air levels. The four tires ranged from 29.5-31 PSI. Is 29.5 low enough to make this sensor come on?

Today was one of the first cold mornings in Phoenix (45º outside when I left the house). I'm sure this is why the pressure was lower than the 32 PSI I filled it at last week, but I didn't think a few PSI would trip the sensor like this. I'll put a little more air in when I get home today, but I'm still wondering what's going on.

Thoughts?

 

I just read on another thread that the TPS trips below 30 PSI. I guess that explains it. I suppose I'll have to fill at a higher pressure than the 32 PSI recommended to avoid these low pressures when it's cold outside.

 

The warning can start as low as 30 PSI. It happened to me over the summer. The internal reading is too low by a pound, at least for me. So I resort to manually checking all tires.

 

Check the pressure in your spare.

 

Unlike the previous generation RX with matching alloy wheel and full size spare,the new generation has a spare is a temp tire.I doubt it has a pressure monitor.