OK strange noise

OK, different car than my other current thread. Hadn't driven it in a while. Since I bought it, the brake warning comes on for 10 secs or so whenever you turn right. I did the blinking lights test and it points at the driver's rear, which is right where this car got hit in a wreck. Otherwise, it drove nicely. I drove it all the way to TX from GA.

But, I think it might have something draining the battery drain as well, so I leave the battery disconnected and don't drive it much. The last time I tried, however, it started making a strange loud noise. It sounds like its coming from behind the dash or behind the electric engine. It sounds like a cross between something scraping or grinding in a rhythmic pattern - but not in sync with the ICE engine RPM or wheel speed - and something trying to suck an empty container - like trying to suck the last of a milkshake through the straw. I drove it home and hadn't messed with it since until yesterday. With my other car needing an HV battery, I need to get this one working.

So, I started it yesterday, sounded fine. Backed out of the driveway and discovered that I had no brake pedal. Like it had lost all of it fluid. I drove it around the block and got a little pedal back, but still not good, and then the loud noise came back. The brake alerts came on, but unlike before, they never went out.

Went home and was idling in the driveway trying to pull codes when the engine dies and the triangle came on. Only code (from TorquePro) was 3191. So, this morning, I cleaned the throttle body and MAF sensor, and cleared the code, and after starting up, it never died, never threw a code. Idled nicely in the driveway for maybe 10 mins. Checked the brake fluid level and it's Max.

So, I got in it to test drive and still don't have much brake pedal. And as soon as I put it in forward gear, the brake warnings lit up and then the loud noise comes back. Parked again, the noise continues. I turn the AC on and off, the fan, the recirculate, anything else electric, and the sound continues. Turn off the key, and when I restart a minute later, the noise is gone.

Do any of these things point to a specific issue you've experienced?

Why am I losing brake pedal when my reservoir is full and I don't see leakage from any wheels/elsewhere? I'd assumed my brake issues were electrical - that the wiring to that driver's rear wheel ABS was shorting somewhere from the wreck. It drove fine doing that for about a thousand miles, but, now it's changed. Did something happen or is it just progression of the original problem not being repaired?

And what is that noise. My inverter pump is working fine - full of fluid that's flowing like a river. The AC works, and turning it off doesn't affect the noise. The noise continues sitting Ready with the ICE not running. That leaves the electric engine or something not even related to the engine (if this was an ICE-only car, I'd bet anything it's a non-engine problem, but I don't know what problems with the other side of this engine sound like.

If the noise is from something cycling, which it sounds like, it cycles very, very slowly, maybe two revolutions per second. There's a solid beat between each noise, each lasts about a half second. And the noise doesn't sound exactly the same every time. Real close, but a little different too, as if other factors were affecting it, like it gets a good suck of milkshake and then the next one is not so good unless you move the straw. Not consistently, but enough to know that something is changing.

Finally, I recall others having issues with parasitic battery drains. Any good threads on that, info elsewhere, that I can read to learn how to diagnose those?

 

Ok, I should have read threads first, but I like to info-dump before I forget in my old age. I found another thread with an audio recording, and my noise is the same. The OP doesn't follow up that it was solved, but the convo had progressed to suspecting the "brake actuator." Which corresponds to my brakes going out. So, I'm going to go find more brake threads and read the service manual section on brakes. Any advice is still welcomed.

 

Yes, thanks, that's what I'm learning, but in Gen1, they're all separate parts, and all a PITA to replace. Trying to pinpoint which one.

 

I don't have Techstream, so I jumped the pins on the OBDII plug and got the brake codes from the blinking dash lights. 52, 56, and 59.

I'm assuming those refer to:

C1252/52 - Hydraulic brake booster pump motor ON time abnormally long. The fixes are either:
Hydraulic brake booster pump motor
Hydraulic brake booster pump motor circuit
Pressure switch (PH or PL)


C1256/56 - Malfunction of accumulator low pressure. The fixes are:
Accumulator
Pressure switch (PH or PL)
Hydraulic brake booster pump motor


C1259/59 - Malfunction in regenerative of HV ECU.
HV control system
HV ECU

Not sure what that last one is about, or what symptom associates to it. I'm thinking it might clear up and will troubleshoot it last.

Does anyone see a likely culprit in those codes? Looks like it's either the pump motor, accumulator, the pressure switch, or all of them.

Thinking through it, I expect the noise I hear is that pump motor, as in it's running and might not be bad. Maybe, there is a leak that's not letting it build pressure, but it keeps trying. IDK.

 

I think that post is deleted.

 

Great info, sir. Thank you so much. Yes, I recall seeing a section on the blink page about generic codes, probably why I was thinking to ignore it.

I've never gotten an XP machine to run the Techstream copy I bought online, so much of the diagnostic part will be difficult. However, I have a parts car (maybe two). Would my chances for success be good, assuming the used parts were good, just swapping all of them in? Except it could still be the wiring, of course.

My guess is a leak. It's only made that noise a short time, two short drives. Sounds like it still works, just keeps sucking air. Would swapping in parts fix the common leak points?

Looking at the price of these parts, it's not likely I'd buy new ones for this old car. I'm already needing a battery in another car, between that and selling the cat assembly, I'd get my money out of it. But, this one has life left, if I fix that noise cheap.

 

That assembly circled is the one that comes out the wheel well? IIRC, a thread said Toyota calls it a 10-hour job requiring the AC be discharged and disconnected. But one guy found an easier way, then another guy found a way he says can do the job in two hours (that means eight for me). Does that sound like the same part?

Here's that thread. He describes the process in Post #3.

Hi! I need advice changing the brake actuator on classic prius. | PriusChat

 

Well, heck, not sure where I came up with the idea Ol Drippy's way would take 2 hours. And yeah, I had read all that mix up with part names. I noticed confusing references in the service manual as well.

So, this car may be toast. Not worth those expensive parts, not worth 10 hours or more of labor, not worth evacuating the AC. Even scavenging the parts off my other car adds several more hours of labor.

My last chance is that it's just a leak, such that if I find and repair the leak, then bleed the brakes, I could be good. I have a likely suspect - that rear driver's side wheel. That's where the wreck was, that's what the dash screen pointed to when I did the self-test. I looked at it and didn't see anything wrong, but I thought it was electrical because the ABS wiring was dislodged. Now, I'm thinking it's a leaking air issue,and not that wiring. Not sure what I'll be looking for, but I'll look at it again this evening

 

Yeah, fluid is still MAX level. I wonder if there's any such valves back by the rear wheel that could have been damaged in wreck?

 

Well dang, I'm too old, and not old enough. I run Windows7. probably easier to upgrade to 10 than find an old XP. Thanks.

 

I should mention that if you like train wrecks, I try to document my escapades here. I have no pride and am a constant source of entertainment for my diesel forum buddies. So...

This is going to be fun. From the different descriptions I've read for replacing the brake booster assembly, I think it can come out the top or the bottom. I may end up doing both as I pull it from my parts car and swap it to my rebuild car. On the parts car, I don't care about AC lines, connectors, etc. And, I've already got the inverter out and will be removing the brake actuator assembly as well. I'm assuming the service manual says to disco the AC lines because it intends it to come out the top, so with all that other stuff out of the way, I don't see why it wouldn't.

Going back in though, I'll have all that stuff in the way. From Ol Drippy's write up, we know it will go in through the bottom/side. However, having pulled the inverters now a couple of times, that task isn't daunting (especially after discovering that the cowl comes off,lol), so I wonder whether it's easier to do that than go in from the bottom. Pulling the fender well isn't hard though either.

I think I'll leave the actuator in the parts car for now, to see if I can remove the booster assembly with it in place, and estimate whether I could get it out with the inverter in place as well. If so, I may go back in from the top. IDK at this point. I'm just old and hate crawling under cars.

Only thing y'all need to know is, whichever way I choose will end up being the harder way.

 

I might pull the master cylinder too, but yeah, it's that PS/Accumulater portion that I gotta wrestle in and out. thx