Smoky350

iTrader: (6)

The sensors on the IS350 suck. I had a low pressure warning light go on and didn't know which tire had low pressure and there was no way of telling which tire it was by looking at it. In my Corvette the display told me which tire has low pressure and also showed me what pressure each tire has. I'm suprised that my lexus sensors are not as good as the ones that chevy makes.

mattssi

Yeah, same gripe here. Cheap-o way of doing things.

Luckily, when mine came on - all 4 tires were actually way low. Stupid temp changes.

VikH

iTrader: (5)

Yea, but at least the roof doesn't fly off while driving

TorontoIS

I didn't realize that the TPMS didn't indicate which tire was low, I assume this is for both the 06 and 07 models.

MrLexIS350

I had the exact same thing happen to me a couple weeks ago. I was driving from Arizona to California. As soon as I get to my destination the sensor goes off, so I automatically think I have a flat. I checked all 4 and they looked fine. I used a pressure checker and the lowest ones were 29 and 30, so I guess if the tire pressure are that low the display comes on?

I guess it's a good thing that it went off, since underflated tires hurt gas mileage and tire wear.

GreyHound

iTrader: (1)

Bad thing is the cost to have new ones added to you system by magic tool at dealer, $120 hour labor. Then if you need to replace one, let’s say lithium battery goes dead, $50. More hassle than its worth. If you put slime or any fix a flat in a tire, ruins sensors.
Government requires them now, because the goobers who don't check their air in tires and crash, sue the tire maker or automaker. Now automaker and tire maker lobbied congress to require sensors so they can say, hey, we put a safety device in tire. So now when the goober who didn't check air and crashes, they cannot sue. Well I hate to tell you, the new law requiring the air pressure sensor, won't change goobers behavior. Goobers that don't check air pressure will still continue to not check air and will just use black tape over the sensor light on dash or pull the bulb.
Government intervention. I check my air because I like the way a car drives with "air in the tires". But I have to pay for these dam air pressure sensors that I don't want or need. They need to quit legislating for stupidity.

Who’s to say the little tire sensors one day won't report where you at to the Government or police one day when they are activated a satellite signal? Conspiracy theory

socalJD

Well if it's mandatory, I'd much rather have TPMS than run-flat tires. Run-flats are the tires that keep on giving, you keep giving more $$$ to the tire shops - No Thank you . . .

AZ IS350

My low pressure warning light came on yesterday for the first time. I checked the tires and they were only 1-2 PSI low (cold) all the way around. I was surprised the sensors were that sensitive. Even driving around a while to warm up the tires didn't help. I ended up having to air each tire up about 1 PSI over to get the warning light off. Such a pain if they are going to be so sensitive and yet not tell you which tire is low.

kensteele

^^hehe so how was it so much easier before we got these sensors?

Just for further discussion, but why would it matter if the system pointed out which tire needed air? There are only four tires and it's just a matter of minutes to discover the truth on your own without help. Sorta like when a light goes out, do you need to really be told?

Wouldn't it be better if Lexus provided sensors that were identical and could be installed and replaced on any tire on any sized vehicle? Imagine if you had to replace a sensor and you need a B-sensor when your P/R tire blew or a C-sensor when your D/L tire was replaced. I haven't thought hard about it but it seems to me the cost associated with identifying the low tire is unnecessary cost. I don't know if that means programming the system using extra steps or what....maybe Lexus didn't have time to redesign for this. That's why you get the neater things in the 2009 version.

p.s. you can get those low pressure indicator caps for your stems that turn from green to red, that way you can visually id the low tire.

Smoky350

iTrader: (6)

It's not needed to point out which tire has what pressure but the lexus and the corvette are about the same price and everybody considers lexus to be much better than chevy. As for the light my mercedes told me exactly which light on which side of the car needed to be replaced. None of those things are needed but it's nice to have them, but I guess that you can't have everything in a car. Whenever I get a new car I miss something from the previous one but like some of the things on the new one.

PS. The sensors on the corvette are all identical and you just have to program them so that the car knows which tire the sensor is going in. A lot of people are programing the sensors them self without going to the dealership. The corvette has all the things that the lexus does and more. Like there are no dore handels inside and outside of the car just buttons, you can drive the car and use navi without any mods, heads up display that shows speed navi and radio, each fob remembers setting for each driver so when you use your fob the car automatically goes to your setting adjusting seats mirror and steering wheel, runflat tires, you can adjust the height of the car by turning a bolt on all 4 corners without changing any shocks. I love the lexus but I thought it would have at least the same toys that the corvette did. I just didn't find a perfect car yet with all the toys in it.

GreyHound

iTrader: (1)

"p.s. you can get those low pressure indicator caps for your stems that turn from green to red, that way you can visually id the low tire. "

Oh hell yeah, from JC whitney, a dollar, 2.95. You don't need a Lithium battery either.
Get some those curb feelers too. look real good

josephdoc

I don't agree with that.
When the message is on even I have no idea which one is sending the message, it actually warns me to check all the tires! I am sure when you have a tire warning light on in the Vette, you will also air up a bit in all other tires.

I wish all cars display meanningful messages for the Engine Check Light instead of just an (!) icon.

justfixit

Understand that this system works on an 18% reduction in air pressure. This means that the TPWS ECU looks for an 18% reduction in air pressure according to where YOU (the owner) initialized them. The sensors do nothing but transmit a signal to the TPWS ECU.
At what psi the light comes on is totally dependent upon the owner. However it has a minimum threshold of 26 psi. Let me try to explain.

Owner A sets his tire pressure to 35 COLD. He then presses and holds the initialization button. His threshold is set to 28 psi. 18% of 35 is 7 and 35 - 7 = 28.
Owner B sets his tire pressure to 35 HOT. He then presses and holds the initialization button. His threshold is set to 28 psi.

Overnight both vehicles are parked and a cold weather condition occurs.

Owner A tire pressures drop to 30 psi. No low tire light on
Owner B tire pressures drop to 30 -31 due to cool down. Then they drop additional 5 psi (due to cold weather) to 25 -26 psi. Low tire light on

Whenever you press and hold initialization button, the low tire light flashes 3 times while the ECU determines where the 18% reduction threshold will occur.

If you have tire pressure set at 44 psi and initialize, your low tire light will come on at 35 psi. 18% of 44 = 9 and 44 -9 = 35

However the TPWS ECU has a fail safe (mandated by gov.) to come on at a minimum of 26 psi.

I am real curious as to how the Corvette sensors work. Are they adjustable to where the threshold can be set by the owner or are they just along for the ride?

Irishman06

the GM/chevy/Delphi sensors are bigger and more expensive. They're derived from actual pressure transducers, and will tell you how much air is in each tire. The denso sensors/receiver are set up as above. They could program it to say "FL tire low", who knows why they didn't.

The nav system lockout is a safety issue, undoubtedly mandated by some Japanese MLIT standard. Same thing with the HUD and such, I'll bet.

AZ IS350

Alright then... guess I never realized this was something I could set myself, so I searched and found this "how to" thread: https://www.clublexus.com/forums/sho...7&postcount=33

Gonna try it. Makes me wonder why the current setting is so far off though. My tire pressure was 33 PSI fronts, 35-36 rears.