Gen 1 ABS failure

Discussion in 'Generation 1 Prius Discussion' started by joedirte, Sep 2, 2018.

  1. joedirte

    joedirte Member

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    2003 Prius
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    Hate to be that guy, but I'm away from service manual. My 2003 with around 100k, ABS died suddenly, first with alarm, pedal went to the floor and no brake for about 2 mins while I checked fluid level, then it went to completely hard pedal.

    Tc CG code flashes ABS 51, 52, 56, 58, 63, 64

    Is this dead booster, maybe just accumulator?


    Edit..

    Cleared ABS codes and 51 comes back. which is
    Malfunction in hydraulic brake booster pump motor

    No fluids, noises. Only occasional click from brake pump during the code flashing.
     
    #1 joedirte, Sep 2, 2018
    Last edited: Sep 2, 2018
  2. ChapmanF

    ChapmanF Senior Member

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    The detection condition for 51 is one of:

    • After turning the key ON, more than 28 amps flow in the pump motor for more than 1 second, OR
    • After turning the key ON, the motor running current does not change by at least 7 amps while it runs (and this is detected 3 times in a row)

    The three pages of workup are pretty basic ... does the pump run if you bring battery power directly to it? (Bring plenty...) If so, check the wiring or connectors, and if they're ok, check the ECU. Or, if direct battery zoobs don't make the pump run, get a pump.

    -Chap
     
  3. joedirte

    joedirte Member

    Joined:
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    Location:
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    Vehicle:
    2003 Prius
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    So checking a few connectors, fuses, etc. I took a look inside ABS relay and cleared codes again and was able to drive for an hour no problems (no ABS light or siren, brakes worked fine)

    While sitting in park and Ready it faulted again 51 and 52. (It was also over 90 and humid)

    After clearing abs and waiting a few hours I just get a constant ABS light flashing, no code.

    The main green ABS relay looks good (80 ohms on coil), but I assume this is the ECU one, I think I saw something about a pump relay and accumulator relay in other location.

    Thanks for conditions, I'll DC clamp pump current. It might be heat soak kind of failure or maybe ECU is flaky


    Edit--

    Code is now only 56 and 64
     
    #3 joedirte, Sep 3, 2018
    Last edited: Sep 3, 2018
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