I recently upgraded my wheels from 17" to 18",after the upgrade was finished,I put the "Tire pressure" buttons,"Pressure Initial" appeared in about 1 minute and disappeared. So does my TPMS have any problem and what can I do next? Besides,where are those TPMS sensors? Are they right inside the wheels? Thanks for all.

 

You're set. The LS430 TPMS is based on the ABS system monitoring tire rotation variance relative to other tires. It's not a direct monitor in each tire. As long as you have already re-initialized, now what you have at moment is the "base" reading for it to determine "low pressure."

The LS430 system, theoretically, if you somehow have all four tires go flat at the same rate, the system would never trigger because the system is tricked into thinking all is good becaues all tires are rotating at same speed.

Not a good system, but that's what a lot of initial TPMS systems were.

 

This morning I tried pressing that button again,but it totally didn't appear,is it ok or not ok?
Do you mean that I need to drive the car until the sensors know the tires were OK?

 

If this is the case, then why does one have to reinitialize the tire pressure after installing four new tires presumably inflated to the same 32 psi recommended pressure? I'd think one should be able to install four new tires of the same brand/model/size, even if they are 1" larger in diameter, inflate them to 32psi, and they will all turn at the same rate.

Since the initialization requires driving between 19-60mph in a straight line, I suspect the computer calculates how many rotations the tires turn (let's assume new tires) per mile during the initialization and expects this rotation rate to within some error tolerance. Then if the new tires you install have a slightly larger diameter eventhough they are inflated to 32psi, the rotation rate will be slower than the computer expects and set off the tire pressure warning eventhough all four tires are at the same 32psi. I know the nav on my wife's 03 LX470 has a button that you push whenever you install new tires. It then compensates the computer for tire wear.