Tire Pressure Warning light

Anyone else experienced this? The Stock OR cold tire pressure is 30 psi as noted on the door jam sticker. Why the hell would I be getting the warning light? 1 difference psi should not be giving the warning light.

Edit/Update: I reset the TPMS and the light finally went away after about 15 minutes of driving. I suppose the dealership at my last service last month could have reset them but hard to say since they were all in spec when I dropped it off. So strange though.

 

That is very strange, mine's at 30 and never triggered a warning. Maybe there's a setting somewhere to adjust the warning PSI threshold

 

Not sure if they work this way, but maybe you're set to 34 lbs and 30 is far enough out of the threshold to trigger just that one? I would imagine the wiggle room is based on what your tpms was set at, not in relation to your other tires...if that makes sense?

 

Try this: Adjust the cold tire pressure to what is on the door jamb. Then do the reset procedure in the owner's manual that's called for when you rotate tires, etc. It's the button on the bottom left of the dash.
When you do the reset, that tells the system the pressure at the time of the reset is the 'correct' pressure. Could be yours was reset with the tires at a higher pressure such that 30psi is now considered low.

From the FSM:

 

I had this issue I replaced tps and no more issues

 

mine were always at 30, all of them seem to drop a pound a month, all went to 27 but no warning but my phone app says they are all low, got colder here and one went to 24, then light came on, pumped all up to 34, lights off but app still says they are all low after 5 hours and 20 miles, I dont take much stock in the whole thing and its just something to play with when bored.......like a fidget spinner

 

If a TPMS reset does not fix the problem, maybe try to get a Scan Tool that can read Toyota TPMS errors.

$200 FOXWELL NT510 Elite fit for Toyota Lexus OBD2 Scanner, Bi-Directional Diagnostic Scan Tool Full System Code Reader, All Service Oil EPB Brake TPS Reset Crankshaft Sensor Relearn, Auto VIN, Free Update

https://www.amazon.com/FOXWELL-Systems-Diagnostic-Bi-Directional-Enhanced/dp/B07Y2QMKJ6?th=1

 

The system low warning threshold is based on each individual tire pressure at the last reset, so the system was probably reset with 35-37 psig in that tire. Set all the pressures where you want them and perform a TPMS reset.

 

All of the above ^^^ System alarms when it drops a certain threshold below its last reset. There is no fixed set point.

 

In full disclosure, I determined that there is a fixed lower threshold limit and I think it's about 24/25 psig, but I forget the exact number right now. In other words, you can't reset the system and get a low threshold below that value. Kinda sucks cause it'd be cool to have the ability to set the system for trail pressures.