Two weeks ago the tire pressure light came on (08 RX 350, 3000 miles). Outside temp in low 20's (F). Called dealer. Young girl in service dept ho-hummed me to insert 35 pounds per tire. Light stayed on for two weeks, regardless of temp in the 40's. Today, inserted air to 35 lbs; froze my 74 year old fingers at gas station . Light went out. Ride is bumpy

 

you have to reset the tire pression monitor every time you add air into the car. So, relieve the pressure to your desired feel, and turn off the engine. Turn the key to the ACC position and then just push and hold the button (under the steering column) for a few seconds.

I think thats how you reset it, consult your manual.

 

That was what I thought, but I found out after I inflated all 5 tires (including the spare) to the same pressure, the light went out without having to push the reset button.

 

No resetting per manual. This actually happened to me the other day, first time I left my RX outside where temp was below freezing point. Checked tire pressure and everything was good, so just drove around as normal. As I drove onto the freeway later, warning light was off.

The rotation of tire builds up hot air within and it adds about 2psi.

 

check spare tire pressure.... had the warning lights 2 weeks ago, checked all pressure 4 tires and they're ok. Took vehicle to the dealership and they told me it's the spare.... apparently, the pressure monitor is also connected to the spare.

 

Set your tire pressure when the tires are cold, including the spare. If you have to adjust the tire pressure, do a reset afterward.