TPWS workings

use advanced search, look for posts containing the term TPMS by me. that should get you started on a bunch of technical info, and if you have follow-up questions, fire away.

 

What psi sets off the alarm?
a drop of psi of 25%

Is it adjustable?
you press the tire button to set it at the current psi, for the alarm no

What about running higher psi?
same you press the tire button to set it at the level you want

What about rotating tires?
rotating tires is m00t because the prius does not tell you which tire is low, you have to find out which one and inflate it to get the light turned off

if any of the tires drop the light will come on.
What about rotating tires with different psi front to rear?
same thing.

Do you need a special tool to reset/register?
yes. you need the dealer's scantool, the dealer's laptop or a third party device
like ones manufactured by bartec, for resetting registered sensors you do not need any tools

If so, does that mean that if I change the psi in my tires or rotate them that I have to have it serviced to keep the TPWS in sync?
no just ignore the tpms when you rotate. the syncing process is easy (once the transmitters are registered) its just a matter of holding that set button down

the only thing you have to be careful about is when the tire needs to be taken off the rim, make sure the tire installer knows you have tpms installed so he does not accidently take out a sensor. make the tire installer walk you around your car to make sure all the sensors are operational

another thing is do not use those spare tire in a can products, it will damage your sensors

yet another thing is the prius only has room in its computer for 4 tires. which means if you switch from summer to snow tires, or you either need to take the tire off the rim, or buy 4 more sensors and have them 'registered' each winter!