I am new to this site. Bought a 2011 Sienna LE (V6) in August.
This morning when I started the car, the Tire Pressure Monitor light went on. We have had trouble with these monitors before. I don't like them and wish they could be turned off. I happened to be going by the dealer this afternoon, so I stoped in. They checked it out and said nothing was wrong. They said it was caused by a change in temperature (it got into the 40's in Tampa this morning). They said whenever we get a big change in temperature they get about 50 cars a day with the same problem. They we nice enough to show me how to turn the light off.