I have a 2009 RX350 and the tire pressure light is on now. I have checked the tire pressures and they are all normal. How does one know which sensor is not working as there isn't anything showing actual individual tire pressures and is only a light?

 

Hi, You will need to take the RX to a shop that has a TPMS scan tool.
They will scan each sensor and tell You which TPMS sensor is not working, they may even be able to reset it, if it's Not defective.
They will be able to tell You the cost to replace it too.
You can purchase a TPMS scan tool and do this Yourself, but the cost of the tool is Expensive and it's not Worth it just to check your TPMS System.
Not a Great Idea, TPMS!

 

Is the light flashing when you first start the vehicle for at least 30 seconds? Or is it just solid? Did you check the air in the spare?

 

I just replaced all 5 plus the spare tire on my 2008.3 out of the 5 sensors were dead as they have a life of around 10 years.I picked up 5 Denso sensors on Ebay for less than $150.

 

Great info here as I also have a 2009 with the same issue. So, do I understand that the pressure in the spare can affect the light even if not mounted on the car? Haven't checked that pressure yet. Thanks to all.

 

The battery in the tire sensors have about ten year life span, my 09 RX has the orange dash light on, had mine checked some dead sensors ..going to wait until tires need replacing later next year...

 

FYI- I have a 2005 RX330, and even though there is a TPMS warning light, there is No TPMS sensor Per Se.
The early model RX's use the Wheel Speed Sensors instead of an actual TPMS sensor.
So when the tire gets low on air,
IE- Smaller Tire Diameter= Equals more Revolutions Per Mile-
Then the Fake TPMS Warning Light comes on!
Solution- Check the Tire Pressures and add air to the tire that's Low, Problem Solved, No Expensive TPMS Sensor Needed.

 

I understand that the spare has a pressure sensor as well, but that is not monitored unless the spare mounted...or is it? The things my "new" 2009 RX does, even though 13 years old, continue to amaze me!

 

The Spare tire is Monitored even if the Spare tire is Not being used.

 

I think I may have asked this before but I don't remember so I will ask again. How difficult is it to change a tire pressure sensor? The light is on but the pressures in the tires are correct and not low. I understand that the spare tire also has a sensor and if the spare is low then it can make the light come on.

 

The sensors last about ten years, then the light comes on... you will have to replace 5 .. my light is on but waiting until i need new tires

 

Whole tire has to come off and then the sensor can be changed. Then, the person putting the new tire on has to be careful not to break them when reinstalling the tire.

Scan tool or TPMS tool can indicate which sensor is bad. Personally, I’ll just be desoldering that smd led in the cluster when I decide to have it apart to change the colour.

 

If the light flashes for a minute or so after you start the car at least 1 is bad. If I comes on solid and stays solid you most likely have a low tire.
edited

 

You'll have to remove the tire/wheel assemblies & bust down the outer side to RnR the sensors including the spare. Really best to replace the sensors when you need to replace the tires....

 

Thanks for all the replies on this subject, I appreciate it.