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Buzz from regenerative breaking

17436 Views 24 Replies 15 Participants Last post by  jjjaaaccckkk123
Anyone else getting a buzz sound occasionally when coming to a stop? I get it once in a while if I am breaking pretty hard, then let up on the break right before I stop. Dealer said they couldn't find anything wrong with the regenerative breaking. It just started after I hit about 8k on my odometer.
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If you're braking hard are you sure its not the ABS?
my regen braking makes a buzzing sound at mild-medium braking.
hard braking the real brakes kick in.
If you're braking hard are you sure its not the ABS?
The Buzz is like a spring unwinding or gears grinding. It is NOT throughout breaking. It happens for a split second when I let off the break after breaking hard, if the car is still moving.
i've come across the same thing. it's like a loud metal squeaking/grinding noise for just a split second...and it's totally random. i can't recreate the problem at will but it happens once in awhile. i have no idea what it is and i'm pretty sure if i take it to the dealer, the sound won't happen. it always works like that.
Never noticed it. Thanks a lot, now it will probably drive me crazy.
High pitch buzz is always there when system is charging. It is loader when brake pedal is applied.

I discovered a new noise at around 400 miles mark. The noise is coming from under the driver's side dashboard and occurs only when brake pedal is applied under 20mph or near stop speeds. The noise is intermittent and reminds of an electric servo opening/closing something, similar to a noise when climate control damper is changing the airflow direction. Lexus service says this noise is normal but I want an explanation on why that noise is occurring and why it was not there when we 1st bought the car. Once I get a more scientific explanation from Lexus service, I will share the info.

On a side note, few days after I noticed that noise the gas engine started on its own while car was parked in the garage. Good think I heard the gas engine running and rushed to the garage to turn off the engine. When I got to the car there was a triangle warning sign flashing on a dash board, navigation screen was poped up with energy screen showing nearly empty battery with only one bar. Both sets of keys were nowhere near the car. I dropped the car off to service department the same day. On the way to serivce department the battery fully charged and lexus did not find any issues with the hybrid system including the battery. To the best of my memory when car was parked in the garage the power was turned off. Now I do not feel comfortable parking the car in the garage because gas engine may decide to start up on its own. I will pursue an explanation from Lexus under what conditions the gas engine may start up on its own when key is outside of the car.
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Update: an intermittent noise coming from driver's side under the dashboard is an electric motor that builds up pressure in the brake booster system. Since the gas engine is not always running, vacuum needed for the brake booster system is not always available.
Lexus service master technician confirmed that gas engine will not start under any circumstances unless car was not powered off. We must have forgotten to hit the power off button when we parked the car, so, once battery level dropped to certain level gas engine kicked in. Perfect explanation and it makes sense. I was able to replicate the issue with a note that once I left the car, it made three tones which was an indication the car was still powered on and key was not detected. Got to be more careful in the future. This hybrid and keyless start is soo new to us.
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There is a speaker that emits sound at low speeds - there was a thread on here to remove that speaker...will see if I can find it.
There is a speaker that emits sound at low speeds - there was a thread on here to remove that speaker...will see if I can find it.
if you remove the bumper, you'll find it on one side (i think the driver side)
I just unplugged it, and now I can enjoy being in stealth mode
There is a speaker that emits sound at low speeds - there was a thread on here to remove that speaker...will see if I can find it.
There was indeed such a thread. But whether there is a speaker that emits sound is seriously in question. My car certainly doesn't have it. I don't know if newer cars do. I think they should just ask pedestrians to get their heads out of their orifices and pay attention.
There was indeed such a thread. But whether there is a speaker that emits sound is seriously in question. My car certainly doesn't have it. I don't know if newer cars do. I think they should just ask pedestrians to get their heads out of their orifices and pay attention.
'12 and newer hybrids have them.
I think they should just ask pedestrians to get their heads out of their orifices and pay attention.
Let me start by saying I am not in favor of the pedestrian warning system, and I am glad that I have a 2011 that doesn't have it. However, your comment is very insenstitve. The warning system is aimed to help blind people that count on the noise of the engine to know if a car is coming across the street. If you were blind I certainly wouldn't say that you have your head stuck anywhere...
'12 and newer hybrids have them.
I have a 2012. It does not have anything of the sort. I suppose that some CT200's may have it, but there is a lot of misinformation being repeated here.
Let me start by saying I am not in favor of the pedestrian warning system, and I am glad that I have a 2011 that doesn't have it. However, your comment is very insenstitve. The warning system is aimed to help blind people that count on the noise of the engine to know if a car is coming across the street. If you were blind I certainly wouldn't say that you have your head stuck anywhere...
Oh, please! That is nonsense. While there is no doubt that blind pedestrians would benefit from this, can you tell me how many blind pedestrians you come across in your lifetime without some warning like a universally recognized white cane being used to assist them, OR A DOG?

I have yet to come even close to running down any sort of pedestrian, since I feel some responsibility to look where the heck I am going, but this cradle to grave government safety harness is getting kind of old. Both pedestrians and drivers share responsibility for careful driving and walking and I don't know ANY blind persons (and I know a few, not a lot) that would walk into the roadway without any warning, noise or not.
Here's some info for you to read. The National Federation of the Blind lobbied hard for this technology. I assume they know more about what blind people want than you do. Acording to this article, this technology also benefits small children, the elderly, runners, cyclists, and other pedestrians.

But hey, I'm not blind and like I said, I'm glad that I don't have it on my car. If I did I'm sure I would be disabling it.

Electric vehicle warning sounds - Wikipedia, the free encyclopedia
Every time I let my foot off the brake, the spaceship sound emits. Every time I stop, it disappears. I have the sound and will remove it in the near future.
There was indeed such a thread. But whether there is a speaker that emits sound is seriously in question. My car certainly doesn't have it. I don't know if newer cars do. I think they should just ask pedestrians to get their heads out of their orifices and pay attention.
My diesel truck also has a speaker to alert pedestrians to my presence. It's activated by the button in the center of my steering wheel.:D

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Let me start by saying I am not in favor of the pedestrian warning system, and I am glad that I have a 2011 that doesn't have it. However, your comment is very insenstitve. The warning system is aimed to help blind people that count on the noise of the engine to know if a car is coming across the street. If you were blind I certainly wouldn't say that you have your head stuck anywhere...
How many blind people do you have wandering around the streets, and what do they do about push bikes? To what extent can we allow for every disability? My biggest problem is people who just walk around paying no attention and without looking!!!!!
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