3rd Generation Prius Accumulator / Actuator / brake problem

Hello everyone,

This will be long, but I’m wondering if anyone is familiar with the problems that I am having. I have searched extensively through the forums, and I have tried to research through the best of my ability.

My first issue deals with the brake possible actuator / accumulator (I apologize I get the braking system mixed up) but I notice when I am holding the brake at a stop, there is a pulsing air sound, almost like air is escaping. I will attach the audio file (actuator) which I hope works... I added the zip files below. The only way to stop this sound is to press the brake pedal very strongly. I don’t notice any issues with braking though, the car stops without issue. I also notice the actuator will come on almost all the time during stops and stop and go traffic, once every 12 seconds give or take even when the car is at a complete stop for awhile. I also know that when the car is off and I open the door, the actuator will come on and will continue every 12 seconds for some minutes even when the car is not on. I have compared this to my friend’s prius who has the exact same 2013 model and his does not do this at all. It will come on just once when you open the door and once when you brake.

The next issue, perhaps the most annoying to me deals with the high pitched sound that comes from the same area I believe as the brake actuator area. It’s very high frequency, the best I can describe it as ringing in the ears. If anyone who is familiar with a hearing test, the high frequency levels that they play in the headset to test your upper range hearing. Now I’m not young, and I know there is another post that talks about this issue saying it’s normal in the regenerative braking system, only young hear it, audio nav system speakers etc., but this sound continues at different high frequencies even when the brake is not being pressed or the accelerator although it does change frequencies at times. I will attach another audio file
(high pitch) and you can hear it more pronounced when the high frequencies change at 38, 42, and 56 seconds even though it is playing through a lot of the clip (must turn up the volume to high). You can also hear it in the (actuator) file in the background. I have also compared these sounds with my friend’s prius and although there is a high pitch sound when pressing the brakes as well as in the background, it’s considerably softer and usually fades out when you let off the brakes. Mine continues at all times mostly when the car is moving and changes frequencies.

My last issue deals with the hybrid battery. I only have 68000 miles yet I got the P0A80 code. I opened the battery up and noticed heavy corrosion on mainly the negative sides of each cell. I cleaned them all, cleaned the fan, reset the codes (original codes were POA80, C1259, C1310) and then ran the Dr Prius app and for load testing bottom voltage, it says suspected problem block 9, which I expected anyway because that was already low when I got the code. From what I read, corrosion on the negative side is due to undercharging due to the car not going on long enough trips, or even possible parasitic draw. Is it possible that the actuator always running too often has drained the hybrid battery over time? From what I read, there is a known issue with the Prius 3rd generation accumulator/actuators, and Toyota will only fix it if it’s drawing up certain codes.

I know this is a very long post but any input on each topic would be greatly appreciated. Thank you

Arron

 

Thank you both for your replies, recommendations, and insight. The codes that popped up on my reader were the P0A80 (replace hybrid battery), C1259 (hybrid vehicle control system regenerative malfunction), and C1310 (Hybrid Vehicle System malfunction). I also had some lights pop up. I read that the later two codes dealt with basically the bad hybrid battery. I too, was guilty of erasing the code when I cleaned my terminals thinking that it was the reason the hybrid battery was low. The codes did not pop back up since and the hybrid battery works again although, It's only about 38% life per the Dr Prius app (after using the prolong charger/discharger). I was hoping that a code would pop up with the actuator, but unfortunately no code has ever popped up. It's unfortunate I've been reading a lot of problems with the 3rd generation Prius actuator, and am not sure if I should look into just paying for it to get replaced or wait for some code to pop up which might never happen..

 

Thank you rjparker, it’s good to know that the brake booster would probably not cause a problem in the hybrid battery. I was surprised that the car would get a bad traction battery at 68k miles and mileage per gallon did not show any sign, but it is true, that it’s a hot climate here. I was also surprised the prolong charger/discharger did not bring as much life to the failing battery as I had hoped. And that thing was not cheap. I was planning on swapping some cells but at 38 percent life, it’s probably better just to replace the whole thing..

I wrote my previous post before your reply, but it had to be reviewed first by moderators. Unfortunately the codes you mentioned does not show in my Prius (thank you for the attachment), I only have the symptoms pointing to the break booster system, and thus I have read from many posts how Toyota will not pay for the servicing if these codes do not actually show up. My car is well under the 150k and still barely within the 10 years but I may be stuck with having to just buy a new brake booster system as well as hybrid battery… I bought this car used last year in March and although I don’t believe it was sold to me with these problems (these symptoms didn’t exist until recently) I’m pretty disappointed with all these things that are happening and feel I probably should have just gone with a gas car despite the rise in gas prices..

 

Thank you for your reply rjparker, do you know if it's dangerous driving around until the code pops up? I don't want to be endangering my life, my family's, or someone else's life on the road if suddenly it stops working. I'll try calling my local Toyota to see if they can do anything about it. Thank you

 

Thank you for your reply. I saw that date of first sale was in early December so there's still a few more months time left until 10 years. I do hope the code shows up while I'm not in a dangerous situation. Ah the fastest I go here on the freeway is 60 here but I always try to drive defensively. I called up someone I dealt with before at Toyota and left a message and will see what they say.

 

Thank you for that great explanation, as long as some braking exists, albeit harder, that is good to know. I think back to those times where there were runaway stops for the large trucks in case they lost their complete braking capability on the downhills; good to know that won't be the case.

I am not sure if the codes will pop, but I hope they do. This condition in my car has been going on for some months now, and has not been getting worse from what I see, and sometimes even goes away in some moments. Actuator keeps coming on at always around 12 seconds repeatedly, no less than that, unless I brake many times in a row. Good to know about the parts availability, although I do have an old 91 Camry without AC that I've been driving around when my Prius was being charged.

Thank you again for all of your replies and knowledge rjparker. And also the other two who initially replied. When I didn't get a reply for some days, I thought I had to just figure out everything on my own.

 

Update. So a couple codes finally popped up C1253 C1256 and POA80 but I guess the C1253 and C1256 disappeared but was stored in the memory since the ABS traction lights went away. I know the bad hybrid battery is one code and the other for the brake booster. I took it in to Toyota, and they said my accumulator is the problem, which is separate from the brake booster assembly covered under the program. They will change out the brake booster but it will cost almost $2000 for the accumulator and close to $4000 for the hybrid battery. So I guess I will be taking the car back after and trying to work on fixing the accumulator and battery on my own. Thank you to everyone who replied.

 

Thank you for your reply, I wanted to try to "educate" myself before calling corporate but it's very confusing and probably even more so across the different generations of Prius. The dealership person was nice and friendly and didn't charge me for the diagnosis. However, they ended up not doing the brake booster pump change either because my hybrid battery was too weak, which is needed to change out the brake booster. So he told me to get the hybrid battery changed out, accumulator changed out, and then bring it back before October when the program expires. I'm not a car person, all this accumulator separate from the brake booster and all this is too confusing. I'll try calling corporate but without a fundamental clear understanding how they all work together, I probably won't get far.

 

Thank you for this, I really appreciate it. I will call them tomorrow. I understand about the hybrid battery also which falls on me. I will reply once I get ahold of them and let you know what they say.