How much lower than the set pressure does it have to drop to trigger an alert?

 

On my other Lexus ES, I think it's below 30 psi. Not sure on the RX - ours is filled with nitro and has never really fluctuated since we took delivery last March.

 

THat's not how it works. The system is set to a specific pressure by the factory ,dealer or owner. I set mine with the pressure listed in the drivers door.
When it drops below X number of psi the light will come on. What is X in PSI?

 

in my ES which I've owned for six years now, the moment any single tire drops below 30 psi, bingo light comes on.

 

I get what you are saying but I guess you've never set it yourself. That number is customizable and not a fixed number. I've owned many Toyota products and have
\initialized the system on all of them. What is the pressure listed on the inside of your drivers door and do you keep it set to that?

 

The low-pressure threshold is generally 6 psi below set pressure.

An improvement with the latest generation RX and NX is that you have a choice during the initialization process of setting to indicated tire pressure (door placard) or set pressure (current tire pressure).
This is a useful tool for technicians, customers often have the low-pressure thresholds set way out of range and selecting "set indicated air pressure" can be performed without having change the actual tire pressure in each tire.

 

Around 20%

 

Thanks

 

I always keep them at 35 cold. yes you are correct I never recorded a SET pressure I suppose so no idea what it is.

 

We keep ours in that PSI range, too.


But one thing I noticed about the Tire Pressure readings on the Lexus app is that they always show a higher pressure. I just assumed that the app is reading the 'hot' pressure, as occurs during driving.

 

you mean the app as opposed to the screen inside I presume. Im not sure the app can read cold psi at least until the car is driven a mile or so.

 

Correct.

Won't look at the in-car warning unless it actually tells me that there is an issue (low pressure).
But I DO like to be informed as to how the tires are doing, so I will occasionally look at the pressures on the Lexus app.

 

FWIW, on my 2013 (no app) the recommended tire pressure is 32 psi and I seem to have a very slow leak in one tire...the warning comes on at 28 psi....