Describe how the tire pressure monitor system works. On my 2006 LS430 Ultra model there are no monitoring devices present in the tire valve stems. There are no monitoring devices evident to the tire guys who install the tires. If you press and hold the tire pressure monitor button under the dash, a light comes on and says pressure monitoring is initializing - you drive it around for a block or so over 19 miles/ hour and the light goes out.
Extra credit - is the spare tire also monitored?
There are air pressure sensors built into the valve stems, including the spare tire.
How do the sensors transmitted the psi to the computer? Since the stems rotate, I assume there are no wires? Do they literally transmit using RF?
Yes, they transmit using RF.
I thought I understood how this all worked until I read your reply (immediately above). If I understand you correctly, you are saying that the tire pressure warning operates with a sensor that detects an abnormally low tire circumference, rather than directly sensing pressure. Is this right? (At least with 2006 models?) If so, what is it triggering off -- sustained differences in apparent wheel speed between the 4 wheels?
Being an impatient SOB, I did a Google search on the subject. I don't know which system the 2006 Lexi use (passive/active), but here is a TireTrack web page that expalins the two types of monitoring system.
Sorry to disagree, Ray, but I believe the 06 uses the abs wheel speed sensors; the wheels do not have tire pressure sensors.
************** I'll take your word for it. I thought that Toyota/Lexus was starting to move away from indirect to direct tire pressure monitoring.The newer models use direct measurement (my '08 LS600hL tells you the exact pressure of each tire - including the spare - on a display that's available in the dash).
GIga
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