Hot Coolant Transfer Pump issues, part 2

This is interesting to me as I have an intemittent squeal on startup on cold mornings (mine is a 2005) as well, but I have noticed it only when depressing the brake pedal firmly (as when starting up), and I can get it to do it at various times during the day but only when the temperature outside is below 40 degrees. I took it to the dealer last winter at about the 5000 mile oil change interval and of course the dreaded "could not reproduce the problem" reply was received. Since the temperature has dropped to the 30s here in Richmond this week the noise has returned. I'm happy to ask the dealer to check the coolant pump but I'm curious if there isn't something else wrong with the relationship to applying th brake. Something keeps telling me it is related to the antilock brake pump, but it is only a guess based on the fact I only hear it when stopped with the brake applied. Letting my foot off the brake stops the screech. I do hear the coolant pump run after shutdown and it sounds normal to me and seems to run for about 15 or 20 seconds. Anyone else noticed this when pressing on the brake??

 

Tideland- you've never had anything done with the coolant system?? That is strange indeed...

Gil- we do notice a kind of pump sound when we press the brake pedal in the morning, that's the ABS pump pressurizing the accumulator, but it's definitely not a squeal. a squeal is not good. if you can make it happen, take it over to the dealer so you can show the tech yourself. take the guy around so he can hear it. the prius shouldn't go around squealing.

 

On my 2004, Im starting to get the same grinding noise on the pump on shutdown...33000miles now...only does it when its cold and its been nasty cold...temp as we speak...a balmy 6 F...sounds similar to the .wav file

 

Thanks Galaxee,

I'm familiar with the sound the ABS system makes normally, but this is a definite squeal or more like a series of chirps. I'm about due for an oil change in a couple of weeks, I'll try to get them to listen again. The squeal is not continuous, but is fairly loud series of chirps. I went to good detail the last time I took it in for this, but they claim they couldn't make it do it. So I guess I'll have to be there with the tech to make it do this while he listens. Hopefully I can get this resolved. The brakes seem to work normally, in fact they can really haul the car down from any speed, I guess due to the regenerative braking working along with the regular brakes. The odd thing is I don't hear the noise when slowing down, or even during hard braking, only while holding my foot on the brake while the car is stopped. I was just curious if anyone else has noticed this noise.

 

the wife's sounded just like the .wav file. I've recorded wav's for Toyota before on industrial equipement. Squeeking main seals on the ICE and for the most part they never replied to my sending the file. Said they were listening to it that's the last I ever heard. I found it myself, incorrectly plumbed PCV system, and fixed it. Sent them a tech report and they changed the design of the PCV system.

 

Hey Gil, if y'can wait till after x-mess when I'm heading back north
and we manage to pull together an RTP-area meetup, bring yer brakes
on down and we can all given it a listen and offer our ivory-tower
theories as to what's going on! [See "road trips" area for details]
.
If it's a very high-pitched tone whose note stays constant, and if
it persists for about half a second after you let completely off the
brake and then stops after the relay click, then you're hearing the
solenoid-driver modulation. My first actuator block was a bit louder
in this regard than the replacement; the new one is much quieter but
it's still there if I listen carefully.
.
_H*

 

My rear brakes did that for a while too, was about to have the husband take it in to the shop with him. He told me it was because I used the parking brake too often (daily) and that it had adjusted the self-adjusting rear brakes too tight. I quit using the parking brake daily and now it's gone.

But there are a ton of things that can make brakes squeak, so that may not be the problem in your car.

 

glad to hear everything turned out okay and the car is working fine.

that tech and the service department get a thumbs up for customer service. wish they were all like that.

 

I'm still going to the dealership to have them inspect the noise. The noise coming from my Prius sounds exactly like this recording. I just find it peculiar the Prius didn't make this type of noise last winter when it was just as cold. Now I have over 22,000 miles on the Prius and it's making this noise everytime I start up and shutdown the car. Maybe I'm paranoid, but I doubt it. Or maybe I'm paranoid but I doubt it. :lol:

 

wow Jonathan!! what a bummer man

 

The car cannot be driven while the flash update is being done. Where they start the update is where the car will stay until done. If the ECU blows, it is basically a dead car stuck in park. They might be able to put the car in neutral with the THHT, otherwise they have to put the front wheels on a dolly and push the car to a parking space.

The battery level refers to the HV battery, not the aux battery. The HV battery can be used while the car is in a standstill by the AC compressor and the DC-DC converter which subs for a traditional alternator. I usually turn off the HVAC when going through a carwash, since the car cannot charge in Neutral. I would do the same when sending the car in for service if I remember. The DC-DC converter usually doesn't take a whole lot of power, but if the car is left on long enough, it could go down to 2 bars where ICE kicks in.
I usually put the car in READY when using my small 12V compressor so I get full voltage and current to the compressor. I sometimes lose one bar, going from 6 down to 5 when I add air to all 4 tires.