Arsenii

First and foremost, I need to apologize for the delay and confusion. It did turn out to be a transmission whine, one of the shift solenoids in particular.

I realized that the sound was coming from the transmission when I took off the air box, then I looked under the car, and it was crystal clear that the sound is coming from the bottom of the transmission. I then tried to shift through gears while the key was in the OFF position, and the sound did change with each shift. With that, I disconnected the wiring harness for shift solenoids, and the sound went away.

This can also explain why EFI relay and TPS sensor are stopping the whine - EFI relay, or lack of thereof, effectively shuts the ECU, and the signal from TPS sensor also comes to the transmission, hence why it was also affecting the sound.

As of right now, the whine is not that bad, so for now I will leave it be, at least until the next oil change.

In the end, I should thank you all for al the help provided, I do appreciate it..

BMeek

Curious. I'm still weirded out that something like a shift solenoid lights up upon key insertion! No one else seems bothered by that bit... is this part of a normal Lexus pre-start proceedure that normally happens quietly upon key insertion? If so, what else goes on?

Arsenii

Judging by the fact that when the key is in the OFF position, EFI relay (and the ECU with it) switches on only for so long, my guess would be that it may be some kind of self-check mechanism that fires up, and then questions some of the components in the car before you go to start it. That can explain why in the OFF position, TPS, A/F sensor heater element, and transmission solenoids have power coming to them. I am sure that it is not a complete list, that is just what I've reached so far..

I have no idea if that is true, that is just my guess made out of what I've seen so far..

P.S. Live and learn, to die a fool.. I never even thought of that before, hence why I was so against the fact that it may be a sound coming from the transmission... At least now I can sleep tight, knowing that it is not a ghost of some kind haunting my car.

Hope this helps and best of luck!

BMeek

It's a paranormal remnant of when "the entire wiring under the dashboard was replaced.".

Arsenii

Interesting theory, but the whine started before the wiring was replaced..
I would say it's more like a vengeful oddment of future expenses..

BMeek

OK... It's a paranormal remnant of when before "the entire wiring under the dashboard was replaced.". An old gremlin whining "Ohoooo ooo! you should've swapped me along with all that fried wiring!".
. But seriously, what a drag that must've been!

I had always assumed that key insertion sensing was all about security and lighting and don't-lock-the-doors-before-the-key's-removed. etc. Your theory is that Toyota implemented a POST back then and maybe found that priming various circuits a few seconds earlier makes for a smoother startup? I guess a modern Lexus could start all that when I walk up with the fob in my pocket or plant my butt in the driver's seat...

Arsenii

I think this preflight check should help with issues like the one presented in this thread, where the car had crank-no-start condition. As it turned out, it was a crankshaft sensor, which prevented the car from starting.
I want to hope that it is the case, since, in some circumstances, it can drastically cut the time it takes to diagnose some no-start conditions..

I know that some European Lexuses unfold mirrors and turn on valet lighting right when you approach the car.. Who knows what else they do at that moment...?