Trailhunter Hybrid high pitched noise

[Bcphoto3]

Just got my TH this weekend.. Less than 350 miles driven (picked up at dealer with 28 miles). One thing I notice is a high pitched noise starting at under 20mph (coming down in speed, coasting) with or without braking. Noise goes away immediately when apply gas. RPMs are 0 when hear the noise. As soon as apply gas and RPMs go up, noise is gone.. Kinda think this might be a Hybrid plant noise, but have had a Prius since 2011 without noise, so not inexperienced with Toyota Hybrids. Wondering if just me, just my TH, maybe I have super senstitve hearing, or are other owners hearing the same thing.

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[SP4RUNNER]

......its your hybrid batt taking over , when you go above a certain speed it turns the motor on.

 

[tacorancher]

It’s the hybrid motor

 

[Bcphoto3]

Thanks guys.. Its just weird that it is more pronounced than in the Prius.. Or maybe we‘ve had the Prius so long I don’t notice anymore and my daily driver was the 4Runner and just different..

 

[Mirach]

I remember seeing in the manual somewhere about it making a high pitched noise on hybrid power for pedestrians to hear.

 

[TacoFreak]

I remember seeing in the manual somewhere about it making a high pitched noise on hybrid power for pedestrians to hear.

Exactly. Below a set speed (don't remember exact speed) when running on the battery it makes Toyota's weird warning sound to warn pedestrians of an approaching vehicle.

 

[MrB4D]

Not sure that the pedestrian noise is the same noise Bcphoto3 is talking about. I have a Trailhunter (since early Oct) and will post some info if same noise

@Bcphoto3 , does it sound like the noise is coming from the passenger side of the vehicle?

 

[jss1]

Mine does the same thing. Kinda annoying.

 

[Bcphoto3]

It sounds like it and it decreases in frequency as the speed decreases. All with tach at zero.

 

[Baltimore]

Just got my TH this weekend.. Less than 350 miles driven (picked up at dealer with 28 miles). One thing I notice is a high pitched noise starting at under 20mph (coming down in speed, coasting) with or without braking. Noise goes away immediately when apply gas. RPMs are 0 when hear the noise. As soon as apply gas and RPMs go up, noise is gone.. Kinda think this might be a Hybrid plant noise, but have had a Prius since 2011 without noise, so not inexperienced with Toyota Hybrids. Wondering if just me, just my TH, maybe I have super senstitve hearing, or are other owners hearing the same thing.

It's a federal safety requirement. Any vehicle operating in battery only mode must make a sound to help alert blind pedestrians to awareness of the vehicle.

• Pedestrian Safety Enhancement Act (PSEA)
  In 2010, Congress established the PSEA to require the National Highway Traffic Safety Administration (NHTSA) to establish safety requirements for EVs. The PSEA requires EVs to produce an alert sound to help pedestrians detect them, especially at low speeds.
  
  

• Acoustic Vehicle Alerting System (AVAS)
  EVs must have an AVAS system that produces a continuous noise level of at least 56 decibels (dBA) when traveling at 12 miles per hour (mph) or slower. The maximum noise level is 75 dBA.
  
  
  
• Sound design
  Automakers can choose the sound, but it must be designed to compensate for wind and road resistance, and be loud enough to be heard in urban areas. For example, the Nissan Leaf emits a musical beeping sound when moving forward and in reverse. The Chevy Bolt has its own AVAS sound.

 

[JustAnotherDingus]

I remember seeing in the manual somewhere about it making a high pitched noise on hybrid power for pedestrians to hear.

Yup yup that’s exactly what that whining noise is and what it’s for. Makes me think of that scene from the office “the Prius is silent under five miles an hour” lol.

But yeah my understanding is there’s some new regulations out there too with making sure pedestrians and cyclists and other vehicles can hear a hybrid or ev coming when it’s coasting on battery power. It’s not my fav noise in the world but it’s pretty easy to tune out after a while.

I’ve been pleasently suprised with how much I can coast around my immediate neighborhood on the battery in the TH. Makes me wish it was a larger cell size. Hopefully that upgrade comes within a few years.

 

[MrB4D]

Sorry for the delay. I have uploaded a clip of the sound (in a zip folder because apparently you cannot upload audio files).

The high pitch whistle is very faint and starts about 1.5s into the clip. If you do an FFT on the sound file (I used Audacity), you can see a spike at~4800Hz and a few much higher (~8kHz, 12kHz, and 16kHz). I suspect the high pitch noise is probably the8+kHz sounds. After using a real-time FFT app Spectroid, the 4.8kHz spike is the prominent frequency of the high pitch whine in the cabin.

Some things to note about the high pitch sound:

• It does not go away at higher speeds (I've heard going 65+mph)
• If you are on the brakes at a stop it will sometimes stop, but if you release any pressure from the brake pedal it will come back
• It is very faint and seems to come from the front passenger side (also where the hybrid inverter is)

Today at lunch I will go and get a recording of the pedestrian alert tone.

EDIT: Crossed off a section and added correction sentence afterwards.

 

[MrB4D]

Full audio file uploaded in zip folder. For this clip, I put my phone on the hood of truck, got in (door close sound), put in gear (parking break noise), you can hear the pulsating whir that is the pedestrian noise as I idled around parking lot getting up to ~10mph, stopped and took phone off of hood. For this reason the FFT in the image below is from 10sec to 15sec.

You will notice how there are peaks at 630Hz, 700Hz, and 785Hz. I suspect this is the whirring pedestrian noise in the comments above. Also notice the noise at 4.8kHz is missing from the audio track (even though I could clearly hear in the cabin).

Anyway, let me know if there are questions or if you hear the noise now that you know what to listen for!

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