Changing/Adjusting Gen 2 Brake Pedal Stroke Sensor.

Discussion in 'Gen 2 Prius Technical Discussion' started by turbo5spd-prius, Oct 25, 2023.

  1. turbo5spd-prius

    turbo5spd-prius Junior Member

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    I've had to change out the brake pedal stroke sensor on my car. I adjusted the old one enough to get brakes to operate correctly after a malfunction. It was fairly easy but the brakes still had hints of odd behavior from time to time.

    Today I replaced the sensor with a used one. The old one was smooth when you moved its lever. The "new" one makes a slight sound, like it has detents, but is smooth when moving it. Does anybody know of different versions of this part?

    When replacing these, you're meant to use a computer based OBDII tool like Techstream or a fancy (expensive usually) reader to calibrate the sensor. When I simply adjusted the old malfunctioning one, it was easy to do it without digital tools to read and calibrate. I simply adjusted it and tried moving the car a bit and judged by the car's response. Two adjustment attempts and it was good.

    With the "new" sensor, it was much more difficult. The new one seemed far more sensitive, with a far narrower window of proper operation. It did help somewhat that the car reacts with a high pitch (likely PWM control) signal to th brakes depending on the position of the sensor's adjustment. When it stopped whining with the pedal untouched, that seemed like the "yes" for the adjustment. Too much one way and the car won't move because of the brakes. Too much the other way and the dreaded warning lights pop up on the dash along with odd brake feel. Does this fit anyone else's experience?

    A word of warning: This sensor is in an odd place with little room to work or reach but it's doable. It will require patience and some bodily contortion, especially if you're not a small framed yoga practitioner... That or taking out more than just the lower driver side dash parts... Jacking or lifting up the car a bit may help with initially exchanging the part but if you do the trial and error calibration, that process will need patience and contortions. If you have the money and patience to set it up, I recommend the proper OBDII tools, not the hacking.
     
  2. Tombukt2

    Tombukt2 Senior Member

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    I guess this is essentially the master cylinder It's bolted to the firewall and your pedal connects to it kind of sits next to the accumulator and pump I didn't realize there was all this work to mess with that I thought that was the part that like almost never went bad but that's interesting out of the five we have here no problems with the stroke simulator or the part you pump with your foot when we change out the accumulator and pump assembly we never let that go dry We squeeze off the hose with a clamp so that stays primed and wet through the whole process.
     
  3. mr_guy_mann

    mr_guy_mann Senior Member

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  4. Tombukt2

    Tombukt2 Senior Member

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    My battery guy told me and showed me the alltel something model 5 I think he said now you can buy one for $100 or something like that It looks like an 8-in screen so on and so forth he says the model six or seven is out so this one is down to like a hundred bucks I held it in my hand and looked at it software reading and whatnot it looks a lot like tech or TIS systems I am seriously considering something like this so I don't have to drag a portable computer around something like a tablet that just can be thrown on a seat and tossed around in a rubber bumper case seems a lot more conducive to this type of work
     
  5. ChapmanF

    ChapmanF Senior Member

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    The stroke sensor is just a rotary sensor that mounts up on the pedal bracket. It's a simple adjustment if you're watching the voltage reading on a scan tool.
     
  6. turbo5spd-prius

    turbo5spd-prius Junior Member

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    That looks nice. In all my hunting, I never stumbled on that one. Will probably have to get one. Have you used this setup?
     
  7. turbo5spd-prius

    turbo5spd-prius Junior Member

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    That looks nice. In all my hunting, I never stumbled on that one. Will probably have to get one. Have you used this setup?
    Yep, and it's a tedious adjustment if you do it via trial and error.
     
  8. mr_guy_mann

    mr_guy_mann Senior Member

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    Ummm, I own and have used all the scantools that I reviewed when I wrote that thread.

    The Autel is pretty good "bang for the buck". Read the entire thread for more info.

    Posted via the PriusChat mobile app.