High-pitched sound

[Miki]

Hi everyone,

I've been experiencing something odd with my car. Initially, when I'm inside, I hear a very high-pitched electrical sound. Once I apply the brakes and come to a complete stop, the noise stops. However, as soon as I start driving again, the sound returns. I find this behavior unusual and was wondering if anyone else has encountered a similar electrical sound. Any insights or suggestions would be greatly appreciated!

Thanks!

 

[omgponies]

Is this the first hybrid you have driven?

 

[sierraCruisin]

Theres a few other threads about this, so you’re not alone. I dont notice it in mine. Im 41 years old and doc says my hearing is great, which Im hiding from my wife.

 

[Miki]

Is this the first hybrid you have driven?

No, it's not my first hybrid. The very first one I drove was a Lexus CT200h, and I never experienced this noise with it.

 

[Miki]

Theres a few other threads about this, so you’re not alone. I dont notice it in mine. Im 41 years old and doc says my hearing is great, which Im hiding from my wife.

Haha, I totally understand you.
I've seen someone mention this issue too—his latest reply suggests it's a Toyota design flaw that can't be fixed, and he even hears the same noise on other LC250s. Sigh.

 

[omgponies]

I've had that noise on every hybrid I've owned, including Lexus CT200h is why I asked

 

[Miki]

I've had that noise on every hybrid I've owned, including Lexus CT200h is why I asked

Thanks for sharing your experience! With my previous CT200h, I didn't have that constant high-pitched noise—it was completely different. I can't exactly pinpoint how it's different, but this current noise gives me a headache; it's like the sound is directly entering my brain and causing pain.

 

[jbe2289]

From other thread, someone that sold their LC because they couldn’t handle the sound, apparently the dealer found that the DC to DC converter for the hybrid system is in the center counsel and the source of the sound. The dealer said this is always under the hood, not inside the cabin in other models. So apparently it is a design flaw with the hybrid LC’s.

 

[Miki]

From other thread, someone that sold their LC because they couldn’t handle the sound, apparently the dealer found that the DC to DC converter for the hybrid system is in the center counsel and the source of the sound. The dealer said this is always under the hood, not inside the cabin in other models. So apparently it is a design flaw with the hybrid LC’s.

I saw that post too, so I'm really at a loss right now. I'm just using music to cover up the noise for the time being.

 

[PACruiser]

I know there are all kinds of fancy noise testing equipment out there that could document and isolate the location.

In the meantime time, have you tried a low cost decibel reader from amazon or a microphone plugged into an electric guitar amp? Those should at least pick up the noise and get your investigation started.

 

[landkruiser]

My '24 has the same issue, and every '25 sitting at the lot at my local dealer has it too. As found in the other thread, it's a design flaw in the hybrid DC converter being moved inside the cabin vs outside the car in all other Toyota hybrids. All LC's have it and you're lucky if you can't hear it (or maybe unlucky you can't hear high frequencies anymore lol). I'm pretty disheartened, maybe angry, that there seems to be no resolution.

The only thing that gives me solace is that it's really only aggravating to me in the passenger seat while driving at city speeds (<45mph). It's slightly quieter in the drivers' seat. On long highway trips, the road noise mostly covers it up. Music mostly covers it up. Since it only kicks in when the hybrid system is active, when sitting at stoplights it's silent, or while sitting while powered on while camping, it's silent. Still, Toyota really needs to issue a recall for this. It's unacceptable an $80k car simulates tinnitus with absolutely no resolution.

For prospective owners I otherwise love my LC but I absolutely wouldn't have bought the car had I known about this issue previously, it's extremely aggravating.

 

[PACruiser]

Well, I guess the good news is that if it is that obvious and in every vehicle it should be relatively easy to document the source, strength, and frequency band so Toyota can fix it.

 

[landkruiser]

Yeah well it's easily seen on a spectrogram at around 13khz, but the dudebros at the dealer seem to have no clue what to do with that information and I don't know what else to do from there. You're more optimistic than me that Toyota will fix it. I'm mostly hoping they fix it in the '26 models and that we can use the part in the '24-25 ones

 

[KWLC250]

My '25 Premium and my wife's '25 LC both have the noise. Seems all '25's have this issue. I plan on bringing it up at my first service. If enough of us document it then maybe they will release a TSB with some sound deadening material or replace the converter all together.

 

[D-mac]

My '25 Premium and my wife's '25 LC both have the noise. Seems all '25's have this issue. I plan on bringing it up at my first service. If enough of us document it then maybe they will release a TSB with some sound deadening material or replace the converter all together.

Or affected people could install sound damping in the transmission tunnel and/or floorboards and test the results.

 

[KWLC250]

Or affected people could install sound damping in the transmission tunnel and/or floorboards and test the results.

I think they said it's from the convertor/inverter inside the center console. So it's in the interior of the vehicle I think.

 

[AlexGates]

Would sound absorbing material (dynamat) knock this out? Would it be safe to put it there? The sound, to me, seems to be coming from the rear pax, right side.

eta: It's the center console.

 

[LCNH]

I hear the high frequency sound only when I apply my brakes and I am slowing down, like for a stop sign or a red light. The sound stops completely and immediately when I come to a complete stop.

 

[KWLC250]

I hear the high frequency sound only when I apply my brakes and I am slowing down, like for a stop sign or a red light. The sound stops completely and immediately when I come to a complete stop.

I also hear it when I apply the brakes, once I've come to full stop and I've completely depressed the brake pedal the sound stops.

 

[landkruiser]

I highly encourage anyone struggling with this sound to spend a few minutes and call Toyota corporate at 1-800-331-4331 to notify them you are affected. According to my local dealer, it's the only way to move the needle on these sort of issues.