My 2008 RX350 is five months old and has 2,200 mile on it. Today the Tire Pressure Warning Light came on. It has gotten a little colder today at 50 degrees and I know that impacts the pressure somewhat. I checked each tire and they were all between 29 and 30 psi cold. I inflated the tires to 34 psi, drove the vehicle and the light went out. Seems to me my light is almost an alarmist since it came on with so little pressure variation and only 1 psi under recommended inflation pressure on one tire.

Anyone else have the light ignite with the pressures so close to recommended inflation guidelines?

btw, I have a very accurate digital gauge so that isn't it.

 

I think you can go to the dealership and ask them to change the default threshold setting of tire pressure sensors. In the 2006 lexus IS, owners can even change the values manually using the built in dash buttons.

 

A little colder you say...lol this morning it was 17

 

In the manual, it describes a way to reset the pressure, look carefully in the TPMS section. Also, I know the PSI is suppose to be 30 on the door jam but I found 35psi is more ideal for even wear of the tire.

 

Actually I found on Page 307 of the manual that you can "Initialize the tire pressure warning system." There is a button way down below the steering wheel with the word "SET" and picture of a tire. There are other buttons in this area too. It was so far below the steering wheel I couldn't find it at first. There is also a button way below the glove box for registering two sets of tire pressure warning valve and transmitter ID codes.

I have not tried to initialize yet, but I'm planning on it.

 

I believe the light comes on at 28 psi, in my opinion, it nice to have early warning. I usually set all my tires at 34 psi anyways, dont forget to check your spare tire too.

 

34 psi seems too hard of a ride on my Michelins. So I brought it down to 32. What do the folks run their tires on?

 

It has been so warm here in Atlanta, we are trying to break the 58 low. I am ready for some cool weather!

 

grr i wish i lived in snowy areas...i live in a place where it doesnt reach below 40 and doesnt reach higher than 80. this may all be good and fun but i dont get the snow i so desire to go skidding on

oh yeh tire question. yes you should reset it using the method described above every time you add pressure to the tires.

 

I would trade places with you anytime lol.

 

I lowered my pressure to 30 psi in each tire and used the "Set" button under the steering wheel as the manual indicated. I should be good to go now with a baseline pressure of 30 psi. Since the manual indicates that the tire(s) have to be "significantly under-inflated" before the low pressure tire warning light appears I presume that means something like 25 psi or thereabouts before the warning light appears. Time will tell.

 

I have had one flat with our RX330. From my experience the pressure was almost zero before the light came on. Treat it like an oil pressure warning-it means "pull over at the first safe place NOW!" Maybe the newer models have an improved system?

 

As the manual states, “Tire pressure falls as the temperature outside falls. Add 2.9 to 4.3 psi to the standard tire inflation pressure.”

A couple of years ago I was in Northern Minnesota in the winter and the outside temperature was –10. The low tire pressure warning light came on and I went to a station to adjust the pressure and found it 4 psi below the standard pressure. As I tried to add pressure, moisture from the compressor tank froze in my valve stem and then the air started to escape from the valve stem on the tire I was inflating. This didn’t help my situation, but finally I was able to dislodge the frozen water, stop the valve stem leak and finally get all the tires to 32 psi, but it wasn’t really necessary, imho. Driving my SUV (not the Lexus) with 28 psi wouldn’t have been an issue and I had no leak, just a variation caused by cooler outside temperature. Therefore my feeling is that the low tire pressure warning light shouldn’t come on with small variations from the standard tire inflation pressure!

 

My tire light came on, of course the Lexus system does not tell you which tire is low . I pulled over and walked around they all looked fine. Next morning before I left I checked the air pressure (cold) and all showed 29 to 29.5 psi with my digital gauge. I start the RX and drove around the block and the darn light was on, so I put 32 psi in the tires and the light went off. The sticker in the door jam indicates 30 psi front and rear cold, if the light comes on at 29 psi thats not much variation .

The system on my Corvette will tell you how much air is in each tire, I guess the old General is not as far behind in technology as people think.

 

You could adjust the tire pressure, for instance, to 28 PSI and then use the "SET" button to set your standard tire pressure as 28 PSI. Then inflate to 30 PSI and you have two more PSI for variation. Of course this adjustment could be different to suit your variation tolerance.