1. Offline

    M&M New Member

    Member Since:
    Jun 7, 2005
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    Location:
    DFW, Texas
    Your Vehicle Year:
    2003 Prius
    Model:
    I
    My Gen I Prius is screeching at me with the BRAKE and ABS lights on, and I hear the electrically actuated pump pulsing as it tries to get pressure into the system. The pedal is spongy and will go all the way down, with the right amount of exerted pressure from my foot.

    I checked the pads and shoes, replaced the pads (worn 5mm down), shoes were as thick as new. The brake fluid level has never gone below minimum, and of course went up for FULL when I pushed the calipers back in for the new pads.

    I have not pulled the codes yet. Sometimes the buzzing and lights go off after 5 minutes and the noise stops.

    I have 165,000 on the car, and had the traction battery replaced at 143,000, so I am not looking forward to another big bill for ABS CPU or actuator assembly replacement. My battery did leak, and needed replacement, but the brake system has shown no leaks, but the pedal has gotten spongier to the point of the system coming on and yelling at me.

    Any similar experiences?
    Thanks,
    M&M
  2. Offline

    usnavystgc Die Hard DIYer

    Member Since:
    Jul 29, 2011
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    Location:
    Bowling Green, KY
    Your Vehicle Year:
    2005 Prius
    Model:
    Four
    I have had no similiar experiences however, spongy pedal usually equals the brakes need to be bled. Unfortunately, the regenerative braking system is more complex than a simple hydraulic system. I would say you definitely need to get the codes to hopefully narrow it down to the regen or hydraulic portion of the system.
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    jhknight Junior Member

    Member Since:
    Oct 15, 2011
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    Location:
    south central Minnesota
    Your Vehicle Year:
    2002 Prius
    Model:
    N/A

    Sounds like ABS problem, get to a dealer immediately.
  4. Offline

    ansobu New Member

    Member Since:
    Sep 9, 2010
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    Location:
    43320
    Your Vehicle Year:
    2001 Prius
    Model:
    N/A
    I have just finished going through HELL with my Gen1 Prius and braking systems issues... All signs were pointing towards the Accumulator / pump / booster... replaced all of them at least once, then at the very end, my non-dealer, hybrid specific shop noticed that a check valve was sticking in the Brake Master Cyclinder! A $150 part! However, to fix, they did have to take off the inverter, so I got some new coolant in the inverter cooling system. All in all, I spent about $4000 between the dealer mis diagnosing it, and the non-dealer repair shop (Mighty Auto Pro in Medina, Oh) in used parts / new parts / and the labor to rip everything out and put it all back in a few times each.
  5. Offline

    M&M New Member

    Member Since:
    Jun 7, 2005
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    Location:
    DFW, Texas
    Your Vehicle Year:
    2003 Prius
    Model:
    I
    Thanks, I don't want to go the same avenue you did...that is why
    I am trying to figure it out without the dealer.....I think mine might be similar...and I hate the idea of having to remove the inverter to get to the brake booster and master cylinder.

    The BRAKE + ABS lights and the buzzer in the cabin have stopped for now, and I think I can do the brake bleeding and see if that improves the sponginess.
  6. Offline

    Steve Norris New Member

    Member Since:
    Aug 14, 2011
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    Location:
    Pearland, TX
    Your Vehicle Year:
    2002 Prius
    Model:
    N/A
    I've also had BRAKE and ABS lights with a shrill alarm intermittently the last two weeks. Took it to the dealer, and they found a code (1251 I think) that meant booster pump failure. Dealer got a booster pump defective reading once, but could not reproduce alarm. The tech said that the booster pump would have to be replaced ($1600), and then if that didn't work then the computer would be next. Sounds the same as one as one of the other stories!
  7. Offline

    Classic_pri Former 2001 Prius 0wner

    Member Since:
    Feb 22, 2008
    Posts:
    46
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    Location:
    Wisconsin
    Your Vehicle Year:
    2007 Prius
    Model:
    II
    It's very difficult in these cars to do ANYTHING without removing something else for access. If a little coolant has to be replaced in the process (plus labor), it's a relatively small price to pay, IMO.

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