RSusi

Read with interest, from other LS430 owners, about low tire pressure warning problems. I have a 2004 LS430 and was wondering how I can find out if my Lexus has the ABS monitoring system or the tire pressure valve stem system? If I have the ABS system then the uneven tireware may be my problem. I have checked the tire pressure, even the spare, and all is OK. I reset the switch and the light goes out. But then after about 15-17 miles the light comes on again. I have about 57,000 miles on the tires (original ) and they are about ready for a change.

ayonnebay

You can't just "reset" it. You must "initialize" the system. After setting your tire pressure in all tires, turn ignition to "ON" , but do not start. Then hold reset button in until the word "INITIALIZE" appears in your dash display.

Then you're good to go.

Walt

airtime

It is not via tire pressure valve stem.

GRAND_LS 4

iTrader: (2)

Its a ABS-based system on the LS430. LS460 got the actual sensors.

fyuen

Which year did the LS start having the tire pressure monitoring system? What's the triggering tire pressure for the alarm?

hatchley

Thanks for your info I had been just clearing the warning lite and not waiting for initialize to appear. Hope this works as Lexus customer service was no help.

schascheck

I have been battling the Low Tire warning and hoped to resolve it by spending $900 and getting new tires yesterday. Light came on again this morning. I just saw the post about Initializing the system and I have now done that. Hope that stops it from coming on again. Thanks for the info.

Jabberwock

All LS430 01-06 use ABS based tire pressure warning system. It uses tire size comparison and actually has absolutely no idea what the actual tire pressures are. It is an effective but primitive system but it works if you understand its limitations.

All LS460's to date use individual tire pressure monitors that use battery operated wireless transmitters mounted in each tire that monitor and report the air pressure in each tire.


These systems continue to evolve...I just saw a commercial where some of the new Nissans have a bell that goes off when the tire you are filling with air comes up to the factory recommended pressure (using its individual tire pressure monitors) to dynamically monitor air pressure.


As a general observation I have been amazed at the number of Lexus and Toyota employees that do not understand how the ABS based TPMS works on these cars. I have had multiple employees tell me to check thje spare when the warning system is showing low pressure. Obviously the spare cannot be part of an ABS based tire pressure warning system so that's a strong indication that the person is clue free on this particular system.

loughery

Thanks Jabber, good explanation! So ABS senses the wheel revolutions?

Jabberwock

Yes ABS system is constantly monitoring and comparing wheel rotation on all 4 wheels. This data can also be used to produce a primitive tire pressure warning system under the assumption that a smaller diameter tire (meaning higher rotations at a given speed) means it has lost air pressure.

Retperio

I am having the same problem. The light is off now on my LS 430 '06 but I expect it to go on again. I just bought this car and the Lexus service mgr. said that if it continues there's a part that can be placed on the ABS to correct the problem. I did the correct thing with the button that's under the dashboard, very hard to get to. I just knew where it was and felt for it and it worked. I bought the car in Texas where it was cold and perhaps that had something to do with it. I will get it fixed in San Diego if it persists. Also, to echo what's been said about the spare. It doesn't affect this problem according to the service mgr. Retperio

VQT

Read the owner manual, in there it show you how to initialize the tire after you adjust the tire pressure. After that the computer will calculater the tire revolutions to indicate if one of the tire is low...
I have to reread it most of the time since I don't remember this thing so I can't really tell you the exactly procedures. esentially which button underneath the steering above the driver knee...

Retperio

The reset button is under the dash above the accelerator pedal. I had to use a round mirror with a stand and a flashlight to find it. Now that I know where it is I can feel it and press it so that it works and turns off the red light. I have it off now but it may go on again even tho' the tire pressure is proper. The service mgr at the Lexus dealer told me they have a part to fix it if the problem continues and it was a warranty item. Hope this helps. Retperio

asdf0123

I got to where it was located..around my area it has dropped below 30 degrees several days now...which could be a contributing factor..my question is during the same time I have my 19's on as well ..will I be able to reset that? Or will I have to live with it considering I chose 19 tire combination outside recommended specs???

Retperio

Even tho you have 19 inch wheels the outer diameter of the wheel is the same as my 18's or 17's. The cold weather doesn't help keep the pressure the same and caused my light to go on.