brake alarm signal warning but no codes

Discussion in 'Gen 2 Prius Main Forum' started by rogerdpack, Sep 11, 2025 at 4:31 PM.

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  1. rogerdpack

    rogerdpack Junior Member

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    Hello all.

    Accidentally let the brake caliper get pushed all the way out when replacing a wheel bearing.

    Brake alarm sound started.

    Unplugged the 12V so caliper would no longer get pushed out.

    Finished the repairs, replaced caliper, bled it using gravity method.

    No codes seem present, no error lights. Sound remains. I assume the power brakes are off still.

    No codes seem to blink with the "diagnostic" screen (paper clip screen LOL). Doing the "ABS reset" there seems to do nothing.

    Still have the car up on jack stands.

    Any advice? :)
     
    #1 rogerdpack, Sep 11, 2025 at 4:31 PM
  2. ChapmanF

    ChapmanF Senior Member

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    Do you mean all the dash lights are doing the steady half-second fast blink?
     
    #2 ChapmanF, Sep 11, 2025 at 4:49 PM
  3. PriusCamper

    PriusCamper Senior Member

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    If it powers up in ready mode and no codes and lights then jump the two pins with the paper clip routine and press brake pedal 8 times to clear the alarm sound, then take it for a test drive.
     
    #3 PriusCamper, Sep 11, 2025 at 5:16 PM
  4. hill

    hill High Fiber Member

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    Our daughter just had the same thing with her similar year Toyota Sienna minivan. No codes. Technicians advice wait to let happens again.

    Yeah, what else can you do.
    .
     
    #4 hill, Sep 12, 2025 at 3:00 PM
  5. rogerdpack

    rogerdpack Junior Member

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    Yeah steady half second blink.

    Did she have the siren/alarm still going?
     
    #5 rogerdpack, Sep 12, 2025 at 3:09 PM
  6. Danno5060

    Danno5060 Active Member

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    Did you bleed both front and rear, or just the affected zone?

    How does the pedal feel?

    Maybe hook up with a scanner that can read the brake ECU?
     
    #6 Danno5060, Sep 12, 2025 at 3:16 PM
  7. rogerdpack

    rogerdpack Junior Member

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    OK so I initially jacked up the car,accidentally pushed out the caliper, then this terrible siren noise started happening, at the same time.

    No codes, I disconnected the 'abs alarm buzzer' but still the noise continued.

    It felt like it was coming from the passenger side glove compartment area. There's about 4 ecu's in there, not sure what each does.

    Then after some investigation I noticed the noise was louder nearest the passenger door lower speaker.

    Touching speaker would affect the noise. Disconnecting the speaker and noise is "fixed" (no longer present).

    I had assumed it was a brake alert noise because it sounded like an annoying siren. Guess the radio chose that exact moment to die. I had been having trouble with the radio before, crackling at first then it quit working at all. Oddly now it actually works again (in the other speakers LOL). I'm not sure if brakes are 100% healthy but at least I know what the sound was. I'll watch it to see if any more brake codes show up.

    I just bled the one corner with new caliper. It feels good. I put a bleeder on like this guy says:
    and fluid came out small steady stream without me pumping the brake pedal so I believe it's at least pressurized. I do have a scanner that can read ABS PID's but not sure which one to know that "all is well" (regenerative is working, etc.) so I'm not entirely sure which to watch but will watch to see if any error codes show up and keep looking.

    At least now I know that if you don't have ABS "light" codes, doing the paper clip 8 brake press thing doesn't do anything. If you clear all codes with a scanner does that also do what the paper clip brake press trick does, I wonder?

    Thanks :)
     
    #7 rogerdpack, Sep 12, 2025 at 6:05 PM
    Last edited: Sep 12, 2025 at 6:13 PM
  8. ChapmanF

    ChapmanF Senior Member

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    Yeah, whichever way you use to clear codes, doing it when there aren't any codes is ... harmless, but takes your time away from other things you might have more fun doing. :)

    Well, as to 'harmless', the pedal-presses method is selective to clear codes just in the brake/skid ECU.

    Depending on the scan tool you use, saying "clear all codes" might broadcast a clear command to all the ECUs in the car. If the engine control module sees a clear request, all of its emission monitors also reset to 'incomplete'. They will eventually complete again as you normally drive, but if you have an inspection coming up soon, the timing could be awkward.
     
    #8 ChapmanF, Sep 12, 2025 at 6:19 PM
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