Hi, everyone:

I searched the threads for this topic, but couldn't really find an answer for my situation.

A couple of weeks ago, on the first real cold morning of the year, my 2006 IS 250 AWD with only 2500 miles on it displayed its first warning light ever -- "Low Tire". I am a person who lives in fear of warning lights, since I don't know diddly about cars. I went to my service station and checked the pressure, they were all fine. The mechanic there told me that sometimes the sensors are very sensitive and the temperature affects them. With my very basic understanding of how cool air contracts, I thought, Okay, that's my answer.

So this morning, the second real cold morning of the year, the light came on again. I didn't have time to check the pressure again, but while driving to work I thought, "If I'm going to treat this light like the boy who cried wolf, how will I know when I really have a low tire?" It seems to me that if I ever really have a low tire on a cold morning, I'll just ignore it, thinking it's the temperature. Not good. And I definitely don't have the time to test the pressure every morning that I have the light on; I'm a harried working mom rushing around without a nanosecond to spare.

Please advise, if you can. I'd appreciate it!

 

I have not had this problem with my IS and the temps here in Chicago have dipped to the 30's. However, I did find a post that relates to your problem:

I believe the reset the poster is talking about is when you initialize the tpms system. Maybe someone else can chime in and confirm this.

 

You are supposed to check your tires cold. By the time you drive to the service station, the pressure may have come up a few pounds.

You can pick up a tire inflater and decent tire gauge for $25-$30, and fill the tires at home.

 

VikDiddy: Thank you for your reply. It sounds like I'm going to have to bite the bullet and call the dealer. I was hoping to avoid any remedy that involves them, but oh well.

 

After my oil change they lowered my PSI to 35psi. My sensors went off 2 weeks later when the weather went from 80 to 40 degrees. Long story short, tell the dealership that you want the psi at 38 to avoid this problem. They said the sensors are designed to go off at 32 psi, but some will go off as high as 34.

 

I don't know what cliverman is talking about. If the pressure in the tire drops due to lower ambient temperature, you are supposed to raise the pressure by adding air, not reset the TPMS to permit the lower pressure.

 

one reason i carry a small air compressor in my car, weighs a couple pounds

 

Bichon, thanks for your input. (You always post such good info.) I think what you're saying is that if the pressure sensor is going off when it's cold, then my tires must really be low because you're supposed to test them in cold air. That when things warm up, I'm really riding around with low tires. The only thing I don't understand is why, then, they were fine at the service station, which is less than 1/2 mile from my home. Could it be that the sensor's being a bit too picky and the pressure is really okay?

I haven't had any trouble, and like I said, the car is prety much brand spankin' new. I also don't think I want to start obsessing about this issue every morning out in my complex's parking lot. My son will never get to school on time again!

 

If you checked them 1/2 mile from your house and they were fine, then the pressure is fine. They won't warm up enough in a 1/2 mile.

 

Half a mile isn't far enough for the tires to get warm, unless you are driving very aggresively. Even so, if the tire pressures are set according to spec, the TPMS warning light should turn off. Could the tires have been intialized at a higher psi?

 

Well, I just spoke to the dealer. Apparently this has been a recurring issue with the IS, and from what they said, only the IS. The recommendation was to jack up the pressure to 34 psi in all four and see if that resolved it. If I still have a problem with the light coming on after doing that, then the sensor needs to be tweaked.

(Hey, this sure beats the cracked cylinder head on my Audi A4 at only 18,000 miles, so I really shouldn't complain!)

 

Keep in mind too that the tire gauges at the gas station are usually a POS and off by a lot. I've seen them up to 5-10 psi off. The $3 cheapo pocket tire gauges you can get in any auto parts store is usually more accurate than the one in the gas station. I carry a digital tire gauge in the glove box of all my cars.

 

yeah the thing that sucks about our TPMS is that it only shows that one of our tires is low and not which tire at that soo it is a good idea to always carry a pressure gauge. i believe some of the newer models ( acura rdx and mdx ) with TPMS not only shows a low warning but the actual pressure of each tire

 

Couldn't agree more. And not just newer models have the feature, but older ones too. My dad's three year old Grand Cherokee shows individual tire pressures in all four tires as well as the spare.

 

Same with my 3 yr old Quest.