Kyosuke86

I just put on some new Toyo tires and for some reason my tire pressure warning light comes on every time I take it up or down my hill. Once I'm on flat ground the warning light goes off. Is it because when the tires are hitting the turns the rubber heats up and expands and therefore air is lost?

Lil4X

You need to recalibrate the "tire pressure warning" for your new tires. Check your owner's manual for the location of the button under the dash to the right of the steering column. Before doing this, check all four tires to be sure they are inflated to the SAME pressure - adjust as necessary. The warning light on your RX is triggered by the difference in rotational speed of the four tires A low tire will "speed up" as its radius decreases due to low air pressure. Good luck!

Todd

the sensors, very easy to do if you don't know what you are doing.

rxdriver

At least in 2004, there aren't sensors on the wheels. I don't believe that's changed.

As Lil4X mentioned, the tire pressure warning system is based on relative tire pressure. The computer (probably the anti-lock brake system) computes the rotational speed of each of the four tires. If one is out of whack compared to the other three, then the light comes on. The RX doesn't use the absolute numerical pressure of each tire.

You're supposed to recalibrate the system regularly, according to the manual. That's unnecessary if you keep all four tires at about the same pressure. As they all go up or down based on the weather, the computer is still OK. But you definitely should recalibrate it if you change tires.

Kyosuke86

Thank you all for your help and quick responses. Now the warning sign doesn't come on and I don't have to worry about taking it to Lexus.