gsrthomas

iTrader: (1)

Since I owned my IS my TPMS went off twice.

First time was early am morning when it was still dark out. I pulled up to the local gas station and filled each tire with 40psi. I didnt have time to guess which tire was low. Visually it seemed like they were fine.

Second was a few days ago after I installed my XM radio. I connected my battery started my car and the TPMS light was on. I pulled over all tires seemed fine. I kept driving. After 20 minutes of driving the TPMS went off. Hasnt came on since. Maybe it had something to do with my disconnecting the battery??

So I want to get a good accurate Tire Pressure Guage for the 2IS to elminate possible guessing.

I went to a local auto store and didnt find any good ones.

What are you guys using?

IS-MIKE

But you might want to check the spare tire it also has a the sensor in it, so you really have 5 tires to keep properly inflated, not 4.
I use an old Pencil Style Pressure Gauge, works well enough for me.

supaIS350

i got one of those digital tire gauges from pepboys.

Joeb427

iTrader: (1)

Accutire makes some nice air pressure gauges.
Even the best gauges are .5 lb off at times.

Bichon

Was it a chilly morning when the light came on? Pressure increases about 1 psi for each 10 degree increase in temperature, so if you are right on the cusp it isn't unusual to have the light come on only on chilly mornings and go off after the tire heats up from driving (and stay off on warmer days).

While it is a good idea to keep the spare properly inflated, it doesn't have a sensor.

gsrthomas

iTrader: (1)

Nope, not chilly at all. Few months ago I filled up my tires to 40psi because I did not want to see that warning again.

I think its pointless to have TPMS without telling you what tire is low. Because both times when my light came up visually the tires were okay.

Bichon

Low profile tires can look visually okay even when they are dangerously low on air, that's why I always keep a tire pressure gauge in the car.

I agree that the TPMS in our cars is poorly implemented -- I much prefer the one in my dad's Jeep that simultaneously displays the actual pressures in each of the four tires.

t.is350.h

iTrader: (3)

really? spare tire has it own tire sensor?

Evitzee

An expensive gauge isn't necessary. I have an old dial one that was a cheapie unit and it works fine. As long as it is consistent you can always compensate if you know it is, say, 2 psi off. We don't have F1 cars where 1/2 psi is a big deal.

IS-MIKE

Maybe the older Lexus' didn't have the sensor in the spare but my 2007 does have have a spare tire with a sensor, I remember the Lexus guy specifically telling me that you can get the warning because of an under inflated spare.
I have read on other forums that people have run into the spare giving the low pressure warning to the system.
I haven't looked at mine but you might have to take the spare back to the dealer if it is low, I read that it might not have a normal stem and is filled with nitrogen gas.

Evitzee

This is the first time I've ever heard that the spare has a sensor. I'd be surprised if it did as it isn't a safety issue since they are only to be used for 50 miles or so. I'm sure someone will verify it or not. As has been demonstrated in the past don't always believe what Lexus tells you, there are often ***** working there, just like everywhere else. I've never checked the stem on my spare, but it would be counterproductive to have a valve that you couldn't fill with air. And why would Lexus fill the spare with Nitrogen if it is only to be used in emergency?

tex2670

Nitrogen is supposed to be able to keep the consistent pressure longer, which would make sense in a spare. Nitro filled tires are supposed to have green valve covers. Costco uses it. There's only limited "evidence" that this is the case tough.

Joeb427

iTrader: (1)

A tire will hold air pressure 6 times longer with nitrogen than regular air.
Maybe that's the reason.
Add in it also the tire pressure doesn't change much when on the road when filled with nitrogen.
I use nitrogen in all my vehicle's tires and keep a 11 gal tank of it on hand to add when necessary..

IS-MIKE

You could look at it the other way, maybe they are trying to make sure that you are protecting yourself and have a properly inflated spare at the ready even if it is only to be used for less than 50 miles.
I had a flat tire on an old car that had also had a flat spare and I remember that sucked finding that out on the side of the road on the freeway.

true, but the Lexus man had some plaques saying he was a certified master or something, so the master was wrong?

Yeah that doesn't make sense, they should have a fitting that you can re-inflate, unless they are trying to get you back to the dealer to sell you more things or something. I'm going to take a look at my spare tonight when I get a chance to see if it has a regular nipple on it.

Bichon

Yes, he was wrong. The spare tire has a normal rubber valve stem and cap, and can be checked and refilled with a normal tire gauge and air compressor. I know, I check mine regularly. The Toyota TPMS sensor has a metal valve stem and an aluminum cap with O-ring. It looks totally different than the 30 cent non-TPMS one in the spare.

This topic has come up before, and another moderator, Lobuxracer, even removed and deflated his spare to prove the point. https://www.clublexus.com/forums/sho...5&postcount=19

Bottom line - no TPMS in the spare.