luca

I did a search on "Tire pressure sensors" and the findings were mixed. Some people think they have "Sensors" in their valve stems and some don't. I am thinking about buying a new set of rims and tires pre bundled from Tire Rack.....Do I need special stems/sensors or not???

airtime

Hi Luca, not sure if this applies to all other years but the way my 04 works is by the car computing the rotation of the wheel is off. Nothing built into the wheel itself as I have after market 20's. You are suppose to inflate all the tires to the desire PSI. Then press the reset button under the dash. This will let the car know. If one of the tires is losing pressure, it would supposedly throw the rotation a bit off. This system is not too accurate as I had a crack rim and was losing about 5 psi per day and it did not sense it for about 2 days. Also, it works best if you are freeway driving as it gives it a chance to sense the balance of all 4 wheels. Other manufacturer has actual PSI and shows you which wheels. This just says "check tire" or an icon on dash IIRC.

Michael21

Appreciate this answer airtime but I just check under my dash and there's no reset button. I have 2 reset buttons, one on the steering wheel (right side) and one next to the trip sets. Can you or anyone else clarify. The Low Tire light is on and I just need to know how to reset it so it goes away.

When you reset it, was the car on, off, key in the ignition but not running?

Thanks

Randy B

You must have sensors in the wheels. The car does not compute rotation of the wheel or hub in order to determine a flat. Take a good look at your valve stems. Are they stiff? Do they have a nut at the base? If so you more than likely have TPMS sensors. If they have a typical moveable floppy rubber valve stem, then they probably do not.

Attached is what one looks like.

Randy B

airtime

Very odd? When I replaced one of my cracked aftermarket wheel recently, they removed the tire off and there was no sensor (though the valve stem was solid and not rubbery). On goes the new wheel with new tires. I was loosing pressure as mentioned about 5 psi per day on another wheel and on the second day, the tire sensor in the car lit up. Reset it, and drove for some more and in a couple of days, the sensor went off again. Now that I had the flat repair, no more light. At least that's my experience for my 2004. 2005-2006 may be different??

Here is what I found on the web related to this for both Toyota and Lexus:

"Direct vs. Indirect: The indirect systems (which are inferior, IMHO) work by measuring and comparing wheel RPMs; there is no requirement that a radio transmitter be used at all, and likewise no requirement that some special gizmo be built into the wheel or tire. Often, these indirect systems take advantage of existing circuits installed as part of the anti-lock braking or traction control system. Direct systems place a pressure gauge and radio transmitter on each wheel, inside the tire. As I mentioned above, the SmarTire direct system adds a temperature gauge and motion detector to further improve the kit."

Can anyone else chime in?

Michael21

Thanks for that information Randy B and usefull to know but I was looking for information on how to clear that red triangle from my dash board. Airtime mentioned something about using the reset but which one, I have one on the steering wheel and one next to the trip indicator

Thanks again

Michael21

I have the 2004 LS

Nelson

The answer depends on what year you have. I can only give information on the 2004 LS that I have. I've checked this carefully.

There is no actual pressure sensor on the 2004 model. It works by sensing the change in sound frequency at the wheel which is an indication that something has changed and thus the pressure must be low.

The reset button (actually two buttons) is not easy to reach. It is far under the dash near your right knee. I believe the button for tire presure reset is the one that is closer to you. In the manual there is information on the reset procedure which involves going on a long freeway drive after pushing the reset button. That procedure seemed to be unrealistic for me.

The reset button is not always the total solution to making the warning go away. Sometimes after a lot of freeway driving (a few days or weeks) the warning will come back. This happened to me when I got new tires. I had the dealer do the reset with their computer and that solved the problem. It was during that series of events that I confirmed the information I'm posting here. The write up person was not sure and had to check to find the answer (he initially thought there were actual pressure sensors...as many people do).

Michael21

Hi Nelson

That's what I was looking for. I just reset the tire low indicator and it went off, thanks and I'll keep the below informaiton in mind next time.

Everyone, thanks again for clarifying

GRAND_LS 4

iTrader: (2)

The 04-06 LS had the old system. The new 07+ Lexus's have the new TPMS systems. So both are correct, except that we didnt have TPMS until the LS460.