I am about to change my tires and wheels on my 2006 GX. Since I am moving to slightly bigger wheels, 18", I will need to replace my TPMS. Searching the forum it sounds like only the dealer can reset the TPMS to read my new sensors. Is this correct?

 

Why replace? The tpms monitor is the valve stem and all it does is report the pressure. Generally speaking, larger rims (smaller tire sidewalls) require higher pressure above current setting.

From my experience, the Toyota systems only report when "x"% below threshold, not above. Additonally, I can't recall specific MY changeover but check your manual as you might be able to recalibrate the set point yourself.

Good luck