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Advice on replacing leaking accumulator

Discussion in 'Gen 3 Prius Main Forum' started by Jim Caldwell, Jul 18, 2021.

  1. Jim Caldwell

    Jim Caldwell Member

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    The accumulator pump is running for 1 sec and then pauses for 3 or 4 seconds and runs again.
    Constantly. Also about every 60 miles the brake boost fails and i get a warning light for brakes and other associated systems. It will stay failed like this for about an equal number of miles,
    and then suddenly the lights clear and brakes working normally again. It cycles through alernate working/ failed over and over. I ran techstream today. There was one dtc for accimulator leaking. Is replacing an accumulator a job a sunday mechanic should not tackle? Also can someone give me a heads up about how much toyota service dept might charge to change it?
     
    #1 Jim Caldwell, Jul 18, 2021
  2. rjparker

    rjparker Tu Humilde Sirviente

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    Take it to Toyota with the codes. It is likely they will replace it free.
     
    #2 rjparker, Jul 18, 2021
  3. ChapmanF

    ChapmanF Senior Member

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    For starters, I second rjparker: you have a 2014, so probably an extended warranty covers you.

    Read the rest here only if that doesn't work out for some reason. :)

    Well, the first order of business is to determine whether the accumulator or the actuator is what you really need, because they are separate assemblies, but either one can fail in a way that gives the symptoms you are having.

    Your symptom is a frequently cycling accumulator pump, but that just means pressure isn't being held in the accumulator; it is leaking back to the reservoir somehow. The leakage path can be through either of these assemblies, possibly through a valve that isn't completely sealing. In terms of number of valves, there are actually more in the actuator assembly (the upper one here), so perhaps more chances of being the culprit.

    [​IMG]

    If you want to tackle the accumulator replacement yourself, a good way to start is to look for a PDF document T-CP-D0H-A510-D. It went with a recall involving accumulators, and because that meant they had to do a lot of them, they devised some clever tools and techniques to speed up the job, because access to the thing is kind of torturous.

    The upper assembly (brake booster in the illustration here, also known as the actuator) is a little less torturous to get to; there are probably more threads and videos about replacing it. Of course it has a bunch more plumbing connected to it.

    Have you got a laptop set up with Techstream? That'll be needed.
     
    #3 ChapmanF, Jul 18, 2021
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