LAKent

Hello all. I picked up a fully optioned Obsidian/light gray '08 LS460 last week. I've been so busy that I didn't start to read the manuals until last night. On page 572 of the main maual, there is a procedure for resetting the warning system: however, my car does not have the reset button that is, as pictured in the manual, below the brake pull. There are trip/reset buttons located above the electric brake mechanism. I called the dealership today -salesman was off and my assigned service rep did not call me back.

I'm sure those of you with this model will have the answer for me.

I'll probably have lots more questions as I read and try things out.

My '07 BMW 335i coupe TPMS is in the dreaded I-Drive.

bob321

It is not visible from the driving position. It's on the bottom/underneath of the dash, just forward of the brake pedal. Need to get on your hands and knees with a flashlight to find it the first time. The outside chime volume control **** is also there. And some other protrusion that feels like the TPS reset button, but isn't, when you are doing it only by touch

As an aside now that it's cooled off outside, if the tire pressure goes 3-4 psi under the manufacturer's 33psi spec, the TPS warning lights come on. More importantly, you can Not use the TPS reset to make it go away until you can get to an air pump. There seems to be a hard coded lower psi limit that can't be overridden.

DrQuality

I concur with bob321.

For the 2007 Lexus LS460, I have just confirmed that the TPMS 'telltale' low pressure warning & yellow warning lights have a built-in 'floor' so as to trigger at no lower than 26-27psi. I did the TPMS tire pressure warning initializing/benchmarking/resetting process … as described in the 2007 Lexus LS460 Owner's Manual (page 513) … when all five tires were all sensing at 30psi on the TFT Multi-Information Display. The telltales are supposed to be set to 25% less than the benchmark (an undocumented parameter, but general conventional wisdom within these boards). That implies, that, were there no telltale floor, the telltales would have been set to trigger at about 22.5psi.

Nevertheless, the telltales triggered at 26-27psi. (I attribute that variance to the undocumented method of 'rounding/truncating' being used to display integer psi values.) That trigger floor works out, btw, to be almost exactly 20% less than the generally recommended pressure of 33psi.

From all that, I am going to surmise the (undocumented) rule is that the telltales are set to trigger at 20% of the initialized/benchmarked/reset pressure, with the minimum allowable initialized/benchmarked/reset pressure being 33psi.

That there is a telltale 'floor' is actually subtly implied in the 2007 Lexus LS460 Owner's Manual (page 513) when it states that "the tire pressure warning system must be initialized(/benchmarked/reset) … when driving with the tires inflated to a higher than standard tire pressure."

Further that implies the advisement in the 2007 Lexus LS460 Owner's Manual (page 598) that "when the battery is removed or discharged, the tire pressure warning system must be initialized(/benchmarked/reset)" is almost certainly moot … if your tires are sensing at 33psi or less.

Summarized another way, it appears the TPMS initializing/benchmarking/resetting pressure process is really only intended for use when the driver is, for whatever reason, running tires at a pressure above the generally recommended pressure of 33psi … and the driver wants to ensure that the telltales trigger at higher values accordingly.

As an aside, I saw a number of discussions on these boards regarding pricing & sourcing of replacement sensors. What I discovered currently (mid-2021) regarding that is that (1) a Denso 5500103 sensor can be sourced from Amazon [ https://amzn.to/3AUxtBH ] or RockAuto [ https://bit.ly/3y37Kp4 ] or DensoProducts [ https://bit.ly/3B1MxxL ] for about $30, (2) that eBay has a number of vendors selling a set of four no-name-brand sensors to replace Toyota 42607-33021 for $35 [ https://ebay.to/2W8VEgK ] and (3) that Discount Tire will sell, then physically & electronically install, an aftermarket sensor for about $60 each.

My understanding is that a Japanese company named Pacific Industrial manufactures the sensors for Denso, that in turn sells them to Toyota.