brake pump stays on...and more

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by rick nepra, Jun 10, 2020.

  1. rick nepra

    rick nepra Junior Member

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    2011 prius came to me after 2 acumulators, 2 brake pumps, one rear caliper replaced. brake pump runs intill it burns it self out with ignition on ( pump turns on with key off normaly when you hit pedal and when drivers door is opened) also one rear wheel at a time locks up. noticed when i pulled in the shop, before installing new pump to replaced second burnt one.more information good flow of brake fluid at all wheels. using snapon triton D8 scanner. also when bleeding right rear only i hear a loud noise like when a pipe has air, penty of flow no bubbles. if i bleed it enough like a half of a gallon of fluid beeping will stop and pump with stop. i think its fixed for 30seconds maybe then there is the pump again running and running. codes
    c1256 accumulator low pressure fault
    c1345 linear valve offset not learned
     
  2. rick nepra

    rick nepra Junior Member

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    no one has anything...………?
     
  3. bisco

    bisco cookie crumbler

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    you need tech stream and the service manual at 'techinfo.toyota.com'
     
  4. ChapmanF

    ChapmanF Senior Member

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    You don't mention replacing the actuator. Has that been done? In Gen 3 it's a separate assembly from the accumulator.

    A C1256 can be caused by a problem either in the accumulator or in the actuator, hence the need to locate the problem before just replacing one or the other. If there's a valve in the actuator not fully closing, the accumulator pump isn't doing anything besides endlessly pumping fluid through it and back to reservoir and around again.
     
  5. TMR-JWAP

    TMR-JWAP Senior Member

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    The most simple answer is to use techstream so you can actually look at pressure and see if it's changing. Maybe the pressure sensor isn't functioning, causing the pump to run non-stop.

    Perhaps obtain the Toyota Repair manual for the car so you can follow Toyo's troubleshooting step by step? I believe it's available on-line.
     
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