Tire Pressure Warning Light

[Sarge538]

I have a 2007 RX-350 and recently the tire pressure light started flashing. Filled to 30lbs. as the door sticker and book say. Could not get light to stop. Called dealer and was told to fill tires to 35lbs. instead of what the book/sticker says. Did that. As I had done before, I pushed button under dash on driver's side as the book says, but still can't get the warning light to stop flashing. Driving me and the wife nuts! Help?

[ZZ4]

Did you check the spare tire? I believe it is also monitored.

[Sarge538]

I have a 2007 RX-350 and recently the tire pressure light started flashing. Filled to 30lbs. as the door sticker and book say. Could not get light to stop. Called dealer and was told to fill tires to 35lbs. instead of what the book/sticker says. Did that. As I had done before, I pushed button under dash on driver's side as the book says, but still can't get the warning light to stop flashing. Driving me and the wife nuts! Help?

Yes sir, I did.

[GDixon]

One of the sensors could be bad. It appears to be time to take the car in for warranty work.

[rx350guy]

Mine came on the other day, and I thought it might be the cold weather, but I took it in to the dealer; and he checked inflation pressures of all four tires, and all four tires were 'low'. He explained that the sensors are set to a 30 psi threshold, so he topped my tires off to 33 psi, and the light is now gone. He also mentioned that the spare can sometimes be the problem as it is also monitored. But so far, so good after topping them off to 33 psi.

Good luck!

[mehullica]

Make sure the MAIN/2nd set switch isn't set to 2nd. It's under the glovebox, right where the r/f passenger can kick the switch with their feet.

[tbear2]

I have a 2007 RX-350 and recently the tire pressure light started flashing. Filled to 30lbs. as the door sticker and book say. Could not get light to stop. Called dealer and was told to fill tires to 35lbs. instead of what the book/sticker says. Did that. As I had done before, I pushed button under dash on driver's side as the book says, but still can't get the warning light to stop flashing. Driving me and the wife nuts! Help?

[neoj]

I have a 2007 RX-350 and recently the tire pressure light started flashing. Filled to 30lbs. as the door sticker and book say. Could not get light to stop. Called dealer and was told to fill tires to 35lbs. instead of what the book/sticker says. Did that. As I had done before, I pushed button under dash on driver's side as the book says, but still can't get the warning light to stop flashing. Driving me and the wife nuts! Help?

I had a same problem also, I left my car outside one night when it was cold and snowing, next morning, when i turn it on, the tire pressure light came up...i was confused for couple days, and the light automatically turn off....eerrrr... :whistles:

[rxpx40]

If I recall correctly, these sensors are sending a RF signal to the car's computer. The frequency is pressure sensitive. When your light comes on at the dash, what it is telling you is not "Your tire(s) have low air pressure." but more along the lines of "One sensor is not reading within an established tolerance limit to all the other sensors"

I believe the sensors are attached to the wheel inside the tire.

I have heard a rumor that the new sensors are in the valve stems, but I haven't seen those yet.

Realize that if all your tires are within say 5 psi (including the spare) and your light is still on at the dash, then a sensor must be bad.

Chris

[steve181]

I had the same problem. I spent some time with the manual and on web blogs. I got the

problem fixed and the light is now out! Here is the definitive info:

1 - The tire pressure monitoring system does monitor the spare. This was the

cause of my problem.

2 - Although the spare is mounted under the car, with the valve facing up,

you can get at that valve by using the screw jack elevator system that is in

the manual. You don't have to remove the spare, only lower it enough to

reach the valve which is mounted facing UP. That was easier than I thought,

once I had carefully read the manual and found all the buttons and things to

use.

3 - After everything is done you have to reset the system by using the

button under the dash, to the right of the wheel. You have to be careful to

use the correct button (the left one) so as not to disable the anti-skid

system.

All in all the system is not bad, but Lexus should do a much better job in

its manual explaining things. This could happen several times per year. I

guess they want to have their service Dept. make money.

[lmarie]

I have a 2007 RX-350 and recently the tire pressure light started flashing. Filled to 30lbs. as the door sticker and book say. Could not get light to stop. Called dealer and was told to fill tires to 35lbs. instead of what the book/sticker says. Did that. As I had done before, I pushed button under dash on driver's side as the book says, but still can't get the warning light to stop flashing. Driving me and the wife nuts! Help?

Mine came on the other day when I went skiing. We checked all the pressures were good. Noticed it was close to needing a tire rotation, so I took my car into Les Schwab and they did the rotation. Warning light was off after that, not sure if Schwab did anything special to make the light go off or if just rotating the tires did the trick.

[bdgarrison]

Just took my Lexus in for a low tire light. They checked all the tires and ended up putting air in the spare tire. I have a feeling they reset the tire pressure light also. Bev

[neoj]

Just took my Lexus in for a low tire light. They checked all the tires and ended up putting air in the spare tire. I have a feeling they reset the tire pressure light also. Bev

I wonder if we bring the car to the dealer with the tire pressure light on, they will fix it for me for free?

[rx350guy]

Just took my Lexus in for a low tire light. They checked all the tires and ended up putting air in the spare tire. I have a feeling they reset the tire pressure light also. Bev

I wonder if we bring the car to the dealer with the tire pressure light on, they will fix it for me for free?

That will depend on the complexity of the problem, I'm sure.. They didn't charge me when they took care of mine; although the solution was simply to top off the tire pressures above the 30 psi threshold, so it took all of about 10 mins tops..

[Hawkswatch]

There’s actually many things that can cause the problem. I’m posting the information below to help out the legions of other RX350 owners looking for a nice concise solution to this irritating problem.

1. Make sure the Main/2nd button, underneath the dash on the passenger side, is set to Main (this is the “out” position of this push button.) This can easily get accidentally pushed in by a passenger’s leg. If you are wondering what this switch does, it’s for people that have two sets of tires with pressure sensors on both sets. This might be for a set of snow tires, for example.

2. Inflate all tires to at least 33psi.

3. Make sure you inflate the spare tire too.

4. Make sure you have aluminum valve stem caps on all tires including the spare. Don’t use plastic or non-aluminum metal
caps. Other metals can actually fuse to the stems over time! You can probably get them at the dealer, or buy some colored ones on Amazon.

5. Press the TPMS reset button underneath the dash on the driver side. There are two buttons near each other - it’s the one on the left.

Well, I hope this information helps someone. The Main/2nd switch is what trips up most people and it wasn’t mentioned on most of the forum posts I've read.

[Zoey61]

I was having the same issue and after reading this thread I went and checked the Main/2nd button under dash on passenger and it was set in to 2nd. I pushed it to the out position of Main and verifed all tires including spare was at 33psi. Turned key on and the tire monitor light went out.  Thanks for the tip on checkng that Main/2nd button on passenger side as somehow someone hit that or pushed it to the 2nd position which caused the light to come on.  Problem solved 

[TG101]

The tire sensor light came on my Lexus yesterday after the temperature droppped to 27 degrees.   I checked the tires and filled them to 30 psi as listed on the door panel.  THis did not fix the problem.  I stopped by a local tire center and was advised to fill tos 34 psi and i did.  I was told to drive it a bit and the problem would go away.  It did not.  The selction was set to MAIN  and I tried the reset button with no luck.  This morning it set all tires and spare to 30 PSI and pushed the reset button still no luck.  To these valves possibly have a batter that may need to be replaced or is one or all of the sensors bad?  This is an irritating problem.  Can anyone offer some suggestions on what more can be done?

[1990LS400]

On 11/14/2019 at 4:53 PM, TG101 said:

The tire sensor light came on my Lexus yesterday after the temperature droppped to 27 degrees.   I checked the tires and filled them to 30 psi as listed on the door panel.  THis did not fix the problem.  I stopped by a local tire center and was advised to fill tos 34 psi and i did.  I was told to drive it a bit and the problem would go away.  It did not.  The selction was set to MAIN  and I tried the reset button with no luck.  This morning it set all tires and spare to 30 PSI and pushed the reset button still no luck.  To these valves possibly have a batter that may need to be replaced or is one or all of the sensors bad?  This is an irritating problem.  Can anyone offer some suggestions on what more can be done?

If the TPMS sensors are the originals, they are at least 12 years old.  Batteries in them often don't last nearly that long.  Any competent tire shop has a tool that can determine which sensor(s) are the problem and their battery strengths.

[RX400h]

Side note: We are only now replacing the remote battery after 14.5 years!

Those Lexus engineers really know how to design efficient battery circuits.

[cd888]

On 2/20/2008 at 11:22 AM, bdgarrison said:

Just took my Lexus in for a low tire light. They checked all the tires and ended up putting air in the spare tire. I have a feeling they reset the tire pressure light also. Bev

I just want to confirm that the spare tire is usually the problem.  My spare was down to 25 psi and as soon as I fill it back up to 32 psi, the warning lights are gone.  The labor part is to use the provided nut in the trunk and use the "elevator" system to lower the spare far enough for you to reach the air stem/nozzle.   Seem kind of dumb Lexus doesn't put this in their manual.

[Nettie]

Each tire, including the spare have a sensor.  If the light is on steady, you should fill the tires to 34lbs even though the door reads 30psi.  Don't forget the spare tire.  If the light blinks then stays on steady, one tire is not communicating with the sensor.  Now you will have to have it diagnosed to find out which sensor is not working.  Pricey little fix.