ABS ACCUMULATOR?

Tiny
BHAMDOC1973
  • MEMBER
  • 2013 TOYOTA PRIUS
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 136,000 MILES
Common issue with these cars and other Toyotas is the abs pump which throws all the lights on the dash, I usually pressure the whole assembly, the accumulator and the booster pump or whatever you call it, which is higher in price, but not knowing which is the issue is what am having a problem with. When the code says low pressure in accumulated, which part is it the 1st or 2nd picture?I usually buy them both as a unit so its less headache in case the other one is what is causing the problem
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Saturday, September 20th, 2025 AT 9:32 AM

14 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
The accumulator is under extremally high pressure so I wouldn't mess with it. I would replace it as a unit. The accumulator is the second part of the picture.
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Sunday, September 21st, 2025 AT 8:57 AM
Tiny
BHAMDOC1973
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  • 2,010 POSTS
Right but what am asking is, when these codes pop up is it usually the accumulator that can be bad alone or does it need to be both the accumulator and the booster assembly? I do not intend in playing with the accumulator but actually replace it. I usually replace both but buying both is so expensive, that is why I want to replace just the accumulator assembly
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Sunday, September 28th, 2025 AT 2:02 PM
Tiny
KEN L
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What codes did you get? I would try to get a used unit from ebay I have had good luck with there parts.
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Monday, September 29th, 2025 AT 9:26 AM
Tiny
BHAMDOC1973
  • MEMBER
  • 2,010 POSTS
C1391
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Monday, September 29th, 2025 AT 11:19 AM
Tiny
KEN L
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Yep, that is an accumulator code aright, pretty straight forward.

C1391 - Abnormal Leak of Accumulator Pressure

I would replace the unit as a whole piece.
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Monday, September 29th, 2025 AT 4:31 PM
Tiny
BHAMDOC1973
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Ya I ordered one, hopefully it will solve it, what in the heck does happen to these? Why do they always go bad? Seen it on Prius, Lexus, rx and more, just weird, and then people say they are reliable, never been a Toyota fan
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Monday, September 29th, 2025 AT 4:46 PM
Tiny
KEN L
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Yep, what happens it he bladder inside of the accumulator ruptured and looses pressure inside the brake fluid. So they need to be replaced. All cars have problem, this is one of Toyotas :/ Let me know what happens.
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Tuesday, September 30th, 2025 AT 9:09 AM
Tiny
BHAMDOC1973
  • MEMBER
  • 2,010 POSTS
I replaced it and did the bleeding procedure twice using the scanner but there is some bubbles coming from the reservoir and a hissing sound, there is no brake fluid leak anywhere so the used one must be bad. I never did have that hiss before, and since the accumulator keeps cycling on and off while parked and off it took down the 12v battery over night
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Wednesday, October 8th, 2025 AT 12:52 PM
Tiny
KEN L
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Wow, that sounds bad, is it a used unit? If so I think you got a bad one. Also, did you use a scanner to open the ABS valves when bleeding? If the system is bled but still makes that noise I would get another ABS unit, thanks for the videos they help.
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Thursday, October 9th, 2025 AT 10:01 AM
Tiny
BHAMDOC1973
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Yes, I let the brake system just like I always do using the Adel scanner. I'll have to open each valve more than once lick the stroker and everything else it does it on his own. All I have to do is open the valves and closing.
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Thursday, October 9th, 2025 AT 10:25 AM
Tiny
KEN L
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If it is bled and it makes that noise the unit is no good and you will need another, it is used correct?
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Friday, October 10th, 2025 AT 8:23 AM
Tiny
BHAMDOC1973
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Yes
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Friday, October 10th, 2025 AT 8:42 AM
Tiny
KEN L
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Sorry about that, I would replace the unit again.
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Saturday, October 11th, 2025 AT 9:06 AM

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