Tire Pressure Sensor Gone?

I believe that the 2000 Sienna uses an indirect method of detecting low tire pressure. Instead of having an air pressure sensor mounted on the valve stem, an indirect method detects low tire pressure by detecting a difference in wheel rotational speed through the antilock brake system (ABS) wheel speed sensors. An under-inflated tire will rotate more slowly than the rest of the tires, and if the computer detects this condition, it will illuminate the warning light.

I don't know why rotating tires would turn on the warning light, and rotating tires yourself or cleaning the brakes should not damage the wheel speed sensors. The ABS system does a self-diagnostic check when the vehicle is first started and move the first 10 feet. If a wheel speed sensor were damaged, the ABS warning light would illuminate.

Correct me if I am wrong but wouldn't an under inflated tire (smaller circumference) have to rotate faster to keep up with the other ones?

Jack G

Oops! I stand corrected!

Great! That's a relieve. I do seem to remember one or more tire would be flatter after the dealer rotated the tires and I had to inflate them. May be they deflated or inflated some of the tires but forgot to do the same on all tires.

Thanks!

If one or more tires are underinflated relative to the other tires, the low tire pressure warning would illuminate. It sounds like your low tire pressure warning system is functioning properly.