guxu

Understood. But as I said, it seems that S-Flow is off by itself on hot days.

ggebhardt

Temperature outside does not seem to make any difference with mine.

After my 5K service, my S-Flow has been disabled. Only way it can turn on is if I push the S-Flow button.

guxu

Tested this afternoon. You can see the passenger temperature was still on even AC was all auto and S-Flow was on. The passenger side had the same amount of air as the driver side. But the back seat vent did not have any air. The outside temperature was 86.

ggebhardt

It is no longer an issue for me.

guxu

To people who are interested in this, I did some more tests this morning. It was 73 outside. With everything on Auto and S-Flow on, whenever I set temperature below 70, the passenger side got the air. Set it above 70, the passenger side air stopped. I thought it's pretty cool.

However, opening the rear door did not trigger the air to rear seats. Not only did we open the rear door, my son was sitting on the back seat. But no air for him when S-Flow was on. Maybe he needs to fasten seat belt (not required in my state) to trigger the air?

ggebhardt

It is not the seat belts, only the opening of the door.

I want all vents to run all the time and NOT temperature dependent. My 450h AC is totally electric and do not see any need this S-Flow cr^p for the 450h.

giovane

So the dealership confirmed they can change the default setting?
I just want to make sure next time I bring the car in they won’t play dumb when I ask them to change it.

ggebhardt

When I was doing the checkin at the Lexus dealer I told him I am wanting the blinks to go from three to five and want the feature that disables the passenger and back seat ac disabled. He looked some what puzzled but I could not remember the name of the feature. After about 1/2 hourkater the guy doing my 5k came out asked what I was talking about. I had taken my iPad with me and forgot that I had downloaded the 450h manual on and told him it was called S-Flow. He came back in a few more minutes, smiling, and said that it was at the top of his techstream list and had never seen it before. He thinks that it was just added as he had not noticed it at the top of the list. Anyway, he disable and all works like I want now.

You should be able to do the same.

Somehow i I got enrolled in some Lexus Experience thing where once every few weeks they ask you about your Lexus. I remember one week they asked in detail about S-Flow and how often I carried passengers. Maybe a bunch of owner complaining helped and got it added to their techstream.

johnhey

I have 2019 RX and have some issues with AC.
I found that AC is not cold enough when I park car under sun for a long time. it takes a long time to cool the car like 15-20 minutes.

Then I discovered about sflow.
when the car was hot (parked under sun for long time)I tuned AC then I turned off sflow (from options on climate menu - I do not have sflow button on dash instead it says "Dual")
I noticed when I turned off sflow, there was much more air coming from front vents. I clearly hear AC fan motor ramping up.
turn on sflow, less air and lower blower fan speed.

when sflow is turned off, it cools the car much faster. is there a way to disable sflow permanently for good?
p.s. I drive car alone most of time so no passengers in front or rear seats

mcomer

The theory behind the Split Flow feature is that when you are alone in the car it will
direct little or no HVAC to the rear or passenger seats. Weight over approx. 40 lbs
in the passenger seat will enable the SIR (airbag) system and the Airbag ON light
will illuminate which brings on the HVAC to the right vents. The default setting is to
Enable S-Flow when the RX starts, dealer can use a Techtool to change default to OFF.

Are you driving with the Drive Mode in "ECO"? Unlike the "Sport" setting, ECO stays on
after an engine restart and affects the HVAC output considerably.

Do you have the air vent(s) other than the drivers closed down? S-Flow is intended to
restrict the air flow without you having to reach and bend but you or your (apparently rare)
passengers can close them off. If closed you will get more air and air noise to the driver.

Does your parking environment lend itself to leaving the sunroof vented? If you are not going
to get dust or leaves floating in, consider that. The Lexus Remote Start App will show the
status of sunroof open if you are inside and it starts to rain...can not close it remotely however

Another Techtool setting to consider if not already enabled, Remote Window Rolldown lets you
press and hold the key fob "unlock" button long enough to partially or fully open the windows
and sunroof. Vents quite a lot of hot air by the time you get in.

johnhey

I usually drive in "Normal" mode, I know echo mode have effect on AC.
So even in normal mode, if I disable sflow, it will enable it again after I use car next time.

for fan speed test and amount of air blowing I did this test
1- trun on AC, do not touch any vents (all front vents and rear are open)
2- manually max the fan speed (using dash button)
Now the air comes from front vents, no air from rear vent
3- from climate menu disable sflow (unselect it)
Now the air comes from both front and rear, however you hear fan motor speeds up surprisingly there will be more air from front vent with sflow off.
remember in both above condition fan speed already set to maximum.

for sake of argument lets say when fan speed is set to max with sflow on, the fan motor runs on 1000 RPM, then when I just turn off sflow fan motor speeds up to 14000 RPM (with out touching fan speed button on dash)

Result is when fan speed set to max sflow on and off has effect on speed. sflow off cools car much faster because it blows more air into cabin

Nail34

You're absolutely correct but it makes no sense. When s-flow is on, there is no flow to the rear and when it's off there is airflow to the rear and but more air up front then when s-flow is on.
Anyway I do not drive in auto and the s-flow remains off when I start the car. If I hit auto by mistake s-flow will come on and will come on again when the car is started until I shut auto off and then shut s-flow off. I could be wrong about auto but that's what it seems to me.

jim256

This may be why you are seeing auto S-Flow re-enabled:

■ Changing from manual S-FLOW mode to automatic S-FLOW mode

Select on the option control screen to disable S-FLOW mode.
Turn the engine switch off.
Wait for 60 minutes or more and change the engine switch to IGNITION ON mode.

Cocal

Did you mean 60 seconds or really 60 minutes?

jim256

That 60 minutes text is copy/paste right out of the manual. It's a few pages beyond the S-Flow description for some reason.