Tire pressure monitor in cold weather
 

I'm certain this has been covered previously, but this is my first winter with my new (to me) LS-460, and a few days now the TPMS has indicated that the pressure is low. One time, just driving it increased the tire temp enough so that the warning light went off.

Do you all just ignore these warnings, or increase the pressure when it's very cold outside?

Thanks!

We've discussed the TPMS extensively in this forum. A search for "TPMS" will bring lots of results.

Here is link to a thread that has some information that should be helpful to you: https://www.clublexus.com/forums/ls-...the-spare.html

If you have any additional questions don't hesitate to let us know.

Thanks very much!

I run 35 PSI in all four tires and spare. I check my tires when they're cold before driving. I wouldn't ignore the low
pressure warning.

Increase the pressure.

I was playing around with the tire sensors lately. It is not clear which PSI number is for which tire. What I did was pump all to very high like 40, then lower one tire , then see which number changes so I know which number is for which tire.

Tire pressure will increase 1-2 psi after running for a while. So when you go to the gas station to pump air, adjust them to 34, then next morning when you start your car cold, the tire PSI will be 33 as the Lexus recommended.

I didn't get warning even if I am at 28-29 PSI

Is the tire sensor more accurate than the tire pressure gauge?

Your question is sort of tricky, but to give you an unqualified answer - the OEM tire pressure sensors on these cars are as accurate or more accurate than any than any handheld tire pressure gauge that you can afford to own.

The reason I am asking is that the reading from my tire pressure gauge is different from my tire sensor. So I don't know which one to trust.

The TPMS sensors are ACCURATE and you can trust them.

Agree! Don't go by your tire gauge. For years I had multiple tire gauges of various types and I always got a different reading from each of them. Two circular gauges that were supposed to be good quality would read 2-3 psi off from each other. I finally bought an expensive gauge meant for track cars, it measures in tenths of a pound. The TMPS reading always agrees with the psi I set with this gauge.

Where do you live? Apparently, if you live at altitude, you can expect that the TPMS sensors will not be the same as your gauge. After I had batteries on a couple of them go out, I replaced the lot. When we checked the pressure it didn't match. I spent a couple weeks trying to reconcile the difference between every tire gauge I used to test the pressure and the reading the TPMS gives. The TPMS is around 2 PSI lower. I tried my own gauges (digital and dial,) the automated and computerized filling system at the Costco, and a pair of borrowed gauges at the auto parts store. All of them were 2-4 PSI higher than the TPMS, with it usually being 2. And everyone was somewhat baffled. Then the guy at the Costco mentions speaking with the rep who sells them their TPMS sensors, and he claims that taking the pressure reading from inside the tire is the culprit, which is where the TPMS sits of course, and that our lower ambient air pressure outside the tire gives us the discrepancy. Ok, whatever. I didn't think there was that much difference from sea level to 5000 ft, but maybe it really does affect the tire readings. So I fill the tires until the TPMS reads 32 and I ignore the external gauge. I don't know which of the two is the "accurate" reading, but 32 or 34, I'm ok with either. :) I guess I'll have to take my tire gauge with me to Vegas next time I'm there and see if the discrepancy changes when at a lower altitude. Ooooh, now I have an excuse to go to Vegas. :)

I have had this issue several times since owning my car (2 years and counting). Of the handful of times the light has come on and shows a tire pressure of 26, it has been nothing more than air leakage from "normal use" (whatever that means). When it hits 28 I think, the light goes off. This most recent time, I checked each tire and found the front passenger side was low. I hit it with air and it inflated to 33. That was 2 weeks ago and so far so good. Only once in those times was it a nail.

About time I got new tires.

I have nitro at 35 psi and it still decrease a little on cold mornings but increase after driving. No warning light in months and a good feature to have.

I pump the air to 33 at 10F the other day. when I drove the car for 5 mins, it go up to 34psi. Today it drops to 31psi cold start at -4F.

Not bad for -4 degrees. Stay warm.