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2007 Prius w/150k miles, original battery - Hybrid synergy drive constantly running. Ideas why?

Discussion in 'Gen 2 Prius Main Forum' started by Warren CA, May 2, 2021.

  1. Warren CA

    Warren CA New Member

    Joined:
    Apr 26, 2021
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    Location:
    California
    Vehicle:
    2007 Prius
    Model:
    II
    My 2007 Prius w/150k miles and original battery has a problem with the Hybrid Synergy Drive constantly running every 10 seconds when driving and at park. Also has a thumping sound. Any ideas why this is happening? Suggestions on fixing?

     
    #1 Warren CA, May 2, 2021
  2. TMR-JWAP

    TMR-JWAP Senior Member

    Joined:
    Aug 12, 2016
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    Location:
    Columbia, SC
    Vehicle:
    2007 Prius
    Model:
    Touring
    That's the brake actuator/accumulator running. Apparently you have a problem with pressure bleeding off. Pretty common problem.

    search Prius brake actuator and you'll get hundreds of hits.

    Sometimes it can be resolved by a brake fluid flush. Sometimes it's only a short term solution. If it gets to the point of getting the red triangle, it normally requires replacement of the actuator.
     
    #2 TMR-JWAP, May 3, 2021
    blaisep, Warren CA, ydpplqbd and 1 other person like this.
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