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Discussion Starter · #1 ·
I've been noticing a noise from the front compartment for a while and it's occurring more frequently. The car's been going OK, but the sound is peculiar. I've asked a couple of service writers and no one can give me any idea. I'm taking it in on Saturday for a check up. BTW, this is a 2005 model, with almost 2000 miles. Temperate climate (so Cal).

The sound is a loud buzzing, and it's not the soft purr of the thermos tank pump. It seems to be located in the back of the inverter, you can feel it. Now here's an odd thing: every morning, when I get ready to head for work, I will open the passenger door to put my gear in. No sound. The I go around and open the driver's side door, at which time the buzz starts up.

This is consistent, it's always and only upon opening the driver's door that the sound starts. After I turn the power on and drive off, the buzzing will continue to come on about every 30 or 45 or 60 seconds, and last about 10 or 15 seconds. When I park, it will continue to happen sporadically for a few minutes after the car is shut off.

Has anyone else experienced this? Any good ideas of what it might be? I just hope that the technician will have a better clue than the service writers.

Thanx, all...
 

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all i can say is, make sure the tech can hear it for himself (reproduce it for him if he's not sure what you did to make the noise happen) and tell him the circumstances that make it start.

the biggest obstacle for service is the dreaded, 'could not reproduce problem' diagnosis.
 

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The sounds from the brake accumulator are often described as a buzz on the boards. People come to notice it at strange times, sometimes long after they have owned the car for a few weeks or even months. Anyway, if the buzz you are hearing sounds like a woodpecker with a balpeen hammer as a beak then I'm pretty sure you are hearing normal brake system noises.
 

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jeromep said:
TAnyway, if the buzz you are hearing sounds like a woodpecker with a balpeen hammer as a beak then I'm pretty sure you are hearing normal brake system noises.
Have to call bullshit on that.

I don't see any evidence that's normal. IF that were normal, you'd think some major automobile review would have noticed it by now. I think I would have noticed it.

Instead what all driving reviews say is ride is pretty pleasant and quiet, and the Prius has one of the highest satisfaction ratings from owners.What some people have noticed is that becasue the motor is especially quiet, other mechanical noises may sometimes be noticed. However, they're actually quieter than most car engine sounds.
 

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"I don't see any evidence that's normal. IF that were normal, you'd think some major automobile review would have noticed it by now. "

Yup, if it isn't in Highlights, er, I mean Motor Trend, Nio won't believe it.

Watch Nio have a seizure over this one:
It only makes that noise while it is lagging on acceleration!
 

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Right, KTPhil has a very good point as usual.

Why should anyone put faith in Consumer Reports, owner satisfaction surveys, any of the many drive test reviews, or thier own ears for that matter. If an anonymous web poster on the internet says there is a sound like a woodpecker with a ballpeen hammer for a beak, that nobody else has noticed, well it must be true.

Score another point of genius for KTphil, my pet legdog.
 

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Cattmatt,

Is it possible to record the buzzing sound? Like someone noted, troubleshooting a problem that cannot be easily/rapidly reproduced is hard enough, but to try to describe a sound is even harder.

Having a recording that the tech can hear makes it much easier to diagnose.

Just a suggestion...
 

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I find it fascinating that Nio, without benefit of actually owning a Prius, is the self-proclaimed expert on what is or isn't normal for the car. We'll have to start calling you NioCarnac with your exceptional powers of remote sensing. He knows far more than someone who has driven their own car and noticed an unusual noise and a change of late. Who needs facts or observation when you can spend all day on the internet reading about it?

Aahhh, this must be another "imagined" problem.
 

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Discussion Starter · #10 ·
what's that buzzing - part 2

Nope, it's not the brake mechanism - I can hear that as a separate sound, just as I can hear the thermos' pump. Not quite a woodpecker with a ballpeen, it's a strong buzz nonetheless. Thanks for the recording suggestion, but I won't have to - this is a constant companion, and occurs consistently. I'll easily be able to demonstrate it.

I'm off to the dealer in a bit, I'll report later on what they find or <gulp> don't find.
 

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What puzzles me is the sound occurs when the door is opened but the car is off. If it was in READY, I might have thought the inverter coolant pump or the inverter itself buzzing. I think the pump runs in Ig-On as well, though the inverter has no high voltage then, so it shouldn't buzz.

I have heard the car whine faintly for several minutes after shutting off which I have attributed to refrigerant settling.
 

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Discussion Starter · #12 ·
DanMan32 said:
What puzzles me is the sound occurs when the door is opened but the car is off. If it was in READY, I might have thought the inverter coolant pump or the inverter itself buzzing. I think the pump runs in Ig-On as well, though the inverter has no high voltage then, so it shouldn't buzz.

I have heard the car whine faintly for several minutes after shutting off which I have attributed to refrigerant settling.
Yes, isn't that weird? And it's ONLY the driver's door, not the passenger. It's not the coolant pump, I'm reasonably certain that the soft purring I can hear less frequently is the pump. This is a sharp buzzing that lasts a good 10 seconds or sometimes more, and it's coming from the back of the inverter -- another earlier service writer actually felt the vibration there.

Anyway, tomorrow I'll be letter the field rep have a go at this, and I'm sure I'll have more info after.

Cheers -
 

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I realize this thread is kinda old, but I don't get
on priusonline quite as often... anyways, the deal
with hearing the sound upon opening the drivers' door is
ENTIRELY normal. The drivers' door switch is monitored by
the brake ECU as well, and fires up the accumulator pump in
expected preparation for you getting in the car and
wanting to use the brakes. Between door-open and the
driver sitting down and hitting the power button is a
nice convenient time to make sure the brake system
is pressurized and ready to rock.
.
I observed this simply by performing various
actions slowly in a quiet place and noticing things
that happened as a result -- try it sometime. Another good
one is to arrive somewhere, power off the car, and then just
sit there and *listen* to everything that happens over the
next couple of minutes.
.
_H*
 

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I hate being left hanging...

and CatMatt never replied. I read this long & spicy thread, complete with cliffhanger... and he never replied. What could have happened??? Did he make it to the dealer? Did they fix the problem??? Was he never heard from again?? Oh, the uncertainty, oh the humanity... :wink:
 

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Discussion Starter · #15 ·
Re: I hate being left hanging...

dave2thec said:
and CatMatt never replied. I read this long & spicy thread, complete with cliffhanger... and he never replied. What could have happened??? Did he make it to the dealer? Did they fix the problem??? Was he never heard from again?? Oh, the uncertainty, oh the humanity... :wink:
But I *did* reply! The subject heading got changed to "what's that buzzing - part 3," I think...but here's my last word on the matter (from several months ago) Oh, and BTW, it's been fine since:

I got my car back today and it's been fixed!

I am told that they replaced the brake system accumulator, and it was under & behind the inverter, thus the weeks ago service writer's thought that the buzzing was actually coming from the back of the inverter.

This incident seems to have been a first for them, perhaps both for the component going bad and for the sticky situation of a technician saying all is well and the customer saying "Sorry Doc, but I want a second opinion." (And being right.) I gather than the technician was brought to task and I imagine that there will be some discussion of what to do if/when this sort of situation arises again. Apparently there is a lot of paperwork to be filed on this issue. I'm just glad that I stood up for myself and didn't let a seeming authority override what my gut said was real.

And incidentally, after driving for a bit I got to a stop light and tried pressing firmly on the brake pedal again -- but the pedal is not as soft now, and it did not come close to depressing down to the floor. And after holding pressure for 10 or 15 seconds, I did hear the old buzzing for a short cycle, but that makes sense, having just put a strain on the system. That's the only time I noted hearing the buzz all day. So I have to figure that the pedal going to the floor was also a symptom of the system leak.
 
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