rsg

There has been a low tire indicator on in my 2004 LS430 for a few weeks. All tires have repeatedly been checked and are at the correct pressure. The Lexus dealer diagnosed the problem as arising from the unequal tread depths on the tires. Has anyone heard of this?
The car has the 5 spoke 18" wheels and the tires have about 10k miles left.

drink300

I don't know how the experts will answer, but my opinion is that the Lexus dealer is blowing smoke. I have had constant problems with my 04 LS430's low tire light. The dealer gave me every excuse in the book before finally just admitting that it's a problem some people experience that they really don't have a fix for. All they knew to do was to overinflate the tires and reset the sensor. It's ridiculous and has seriously affected my respect for the Lexus brand.

GeorgeT

Depends on the method to determine low tire pressure. Up until 2006 or 2007, BMW used the difference in tire rotation to detrermine low tire pressure: less pressure means the tire has a slightly smaller diameter and turns more to travel the same distance as a fully inflated tire. This system uses the ABS sensors to count the rotations and compares left to right. The new system uses actual pressure monitors in the wheels and is much more accurate. If you car has the ABS monitoring system, differences in tire wear could result in the problem you're having.

rsg

I see. That makes sense. Thanks

msrashida

This exact same thing is happening to me now. I recently had to replace one tire and shortly after the low tire indicator lights comes on. I reset it, and it comes back everytime. After reading the manual, it does mention the circumstances where the low tire indicator light would come on. Unequal treadwear is one of the reasons. Because of the way that the tire monitoring system works, ABS, I actually think it's a valid reason. I'm going to go ahead and get 3 other tires. I'll let you know if the light turns off. Cross your fingers.

msrashida

Update: Changed the other tire on the same axle so that they were both the same and the tire pressure indicator light finally went off.

DanozLS430

iTrader: (1)

You solved the mystery. Thanks for posting your reply and hope it helps others with ABS tire sensors and not pressure monitoring sensors. It seems like ABS type were the early stages of pressure monitoring and Lexus did not factor in that the tires wearing out would set off these sensors as low pressure when it is not the case.

DanozLS430...