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Replaced ABS Module, brake not touching button that deactivates break lights

Discussion in 'Gen 3 Prius Technical Discussion' started by Eduardo1982, Jun 23, 2024.

  1. Eduardo1982

    Eduardo1982 New Member

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    I have a 2010 prius and I replaced the brake booster pump and the Brake Master Cylinder (the one that hooks up to the brake pedal).

    After reinstalling everything I noticed that the brake barely touches the button that disengages the brake lights.

    Can someone please advise how I can fix this?

    Attaching a pic. I removed the pin and pushed the brake away so you could see what I mean.

    Thanks in advance.

    Eduardo
     

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  2. ChapmanF

    ChapmanF Senior Member

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    There is an adjustment for that button, if necessary. But because it was presumably adjusted properly before the actuator replacement, I would first double-check that the new actuator is fully seated against the firewall with nothing caught between. There is, for example, a gasket that goes there, and if the new gasket was used and the old one was still stuck in place, that could account for the actuator not being fully seated.

    If you confirm the actuator is fully seated, then first make sure the pedal height is correct (*4 in the drawing). That's adjusted by loosening the clevis locknut and turning the pushrod, then tightening the locknut again.

    [​IMG]

    Only after you know the actuator mounting and pedal height are correct, then adjust the button if you have to.

    Edit: note the pedal height figure is from the actual metal floor panel, not the carpet or floor mat. Carpet gets turned back to measure.
     

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  3. Tombukt2

    Tombukt2 Senior Member

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    And I'm assuming the green part is fully seated in the brown part which is seated in the metal it is clicked in completely? It sort of looks like it. That's why I still like the old threaded adjustment and most of my Corollas and hachirokus and all that. At least if something's bent or something you have a few threads and a nut of course you can always bend the metal that's bent to.
     
  4. Eduardo1982

    Eduardo1982 New Member

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    Thank you! This helps a lot. I did check and the actuator is fully seated

    1. I tried loosening the clevis lock nut on the actuator that I removed, it's tight and I couldn't loosen it. How should it be done?

    2. Do you or anyone else know of a hack to unscrewing the nut that holds the sensor? It's tight and I don't have much grip with my fingers.

    Thank you! Any idea on how I can unscrew the brown part? It's tight and I don't have much grip.
     
    #4 Eduardo1982, Jun 24, 2024
    Last edited by a moderator: Jun 25, 2024
  5. ChapmanF

    ChapmanF Senior Member

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    As long as the recent repair work

    1. did touch the brake actuator
    2. did touch the pedal connection to the new actuator's pushrod, and
    3. did not touch the green/brown pushbutton adjustment

    I would still proceed by making sure 1 and 2 are right before any fiddling with 3.
     
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  6. Eduardo1982

    Eduardo1982 New Member

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    Hi Chapman,

    Should I try to loosen the clevis lock nut while it is still connected to the pedal if the height needs to be adjusted?

    I finally was able to adjust the sensor, I was trying to turn the brown piece instead of the sensor itself. o_O
     
  7. Tombukt2

    Tombukt2 Senior Member

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    Yes the whole sensor twist and that's your thread this is how they all are now Chapman's just saying if it all was correct before it should be real close now!?. When replacing master cylinders on older Corollas and things like that which was a metal connection with a pin pushed through the pedal with a pen that holds that in and then a real gold nut on the bracket that you adjusted with a 10 mm wrench and then you turned the shaft until you have the required play and then you lock the lock nut down here they've turned all this to plastic so you have to kind of be careful. On the older cars there was a rubber pad on the flat where the brake button actually gets pushed they've eliminated the piece of rubber so now the metal is the only thing touching the button.
     
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  8. ChapmanF

    ChapmanF Senior Member

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    Have you measured the pedal height (down to the metal floor, with the carpet turned back) and compared to the drawing to make sure it's right?

    If the pedal height is low, and you've now adjusted the light button to match, I would adjust the light button back where it was, and fix the pedal height. (Double-check the direction you're trying to turn the clevis locknut—to loosen it, you try to screw it "down" onto the pushrod, away from the clevis. Yes, loosening it while the pedal's attached is fine, even saves you having to find some other way to hold the clevis from turning.)

    Once you have the height where it belongs, you jam it from turning again by screwing the locknut back "out" against the clevis.

    Comparing importance of adjustments, the brake-light button adjustment matters to when your brake lights come on (and cruise gets canceled), but the pedal height matters to how far you can push the brake piston. If the height is too low, you can't use the full stroke. (Which maybe doesn't matter much, until that one time you wish you could've used the full stroke.)
     
  9. Seymour1

    Seymour1 Junior Member

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  10. Seymour1

    Seymour1 Junior Member

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    I replaced the booster pump and master cylinder with new parts on my 2010 Prius. I visually compared the clevis adjustment bolt of the new and old parts. They were close. When I put in the mastercylinder , I pulled the petal up and heard a crunch. I had forced to brake light switch up and had to re-adjust it.
    I bled the brakes without going into invalid mode because I watched the wrong youtube. Still, I thought that I removed all the air. I did not bleed the bleeder screw (for ABS, skid control or stroke simulator) that is under the hood. I get a C1203, C1345, and C1451 codes relating to ABS. And, I am unable to go into invalid mode. I tried many times. There is a youtube where the man uses a paperclip on the OBD connector to go into "service mode" to bleed the brakes. Does this work as good as official "invalid mode"?
    So, I wanted to measure the distance from metal floorboard to the top of the brake petal. It appears that the floor mat might be stapled down in the front. Do I remove the front seat in order to fold back the carprt? I measued the petal free play in a crude inaccurate manner. I was careful to not push hard enough to move brake fluid from the master cylinder. It is 12mm or so. This is clearly greater than the 6mm max allowed.
    What stops the petal when my foot is off the brake? I think it is the internals of the master cylinder. Maybe I am wrong. It should not be the petal arm hitting th light switch. So, the free play cannot be adjusted if I am right. The push down and let up are set by the master cylinder. IMG_2743.JPG
     
  11. ChapmanF

    ChapmanF Senior Member

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    On a new part, the C1203 should go away the same time the C1345 does after bleeding is complete and the linear solenoid offset has been learned. But the C1451 code is going to firmly insist that you properly bleed the system. The code is made to stay put until you've done that; it is even nonvolatile, so removing the power won't clear it. Toyota's serious about that one.
     
  12. Eduardo1982

    Eduardo1982 New Member

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    I bought a scanner to follow the directions on bleeding the ABS. It took me to all four wheels, then the stroke simulator, and then again the front wheels.

    From that point it tell you that the next step is to do the linear valve offset. That takes 120 seconds. From there you should be good to go.

    Make sure you buy a scanner that works with Toyota cars and does both the ABS Bleeding and the linear valve offset.
     
  13. Eduardo1982

    Eduardo1982 New Member

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    Thank you very much. All measured and adjusted accordingly. I appreciate you sharing your knowledge.
     
  14. ASRDogman

    ASRDogman Senior Member

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    So, everything is working correctly? And the car runs correctly now?
     
  15. Eduardo1982

    Eduardo1982 New Member

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    Yes sir, I have been driving it since Tuesday. No warning lights on the dash. Brakes feel good. I tested slamming the brakes a few times and they responded as expected.
     
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  16. Seymour1

    Seymour1 Junior Member

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  17. Seymour1

    Seymour1 Junior Member

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    Can you recommend scanner software that will do the ABS bleeding and linear valve offset? Will Torque Pro do that? I have an iphone and an OBD2 plug-in bluetooth that is compatible with my iphone. Torque Pro works with bluetooth and an iphone. And, I have a laptop and a Wi-fi plug-in to talk to my laptop. I have T S but I cannot get it to connect to my car. I think maybe that I need a driver for the J2534 cable, but I am only smart enough to get myself into trouble. It has been too hot outside for several days to work on the car. Meanwhile, I am trying to learn and make a plan.
    Any idea why I cannot get into invalid mode?
    Thanks for your help.
     
  18. ChapmanF

    ChapmanF Senior Member

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    With a C1451, you are pretty much locked out of doing anything except bleeding the brakes. That's the purpose of that code.
     
  19. Eduardo1982

    Eduardo1982 New Member

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    First time doing a job like this. I did some research and talked to support teams. The one that was reasonably priced and did these two special functions is the Foxwell NT710.

    The video that shows I think the same steps is this one, even though it is with a different type of scanner:


    A far as the "invalid mode" question, I honestly don't know what that is. Maybe one of the most experienced guys here can answer that.
     
  20. ChapmanF

    ChapmanF Senior Member

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    It is described in the repair manual, where its full name is "ECB Invalid Mode". It is simply a mode you can enter that will temporarily prevent the brake electronics from trying to operate the brakes or set trouble codes while you are doing some kind of work that would otherwise be detected as a brake fault. Fluid replacement (where the system is already filled with old fluid and does not need any bleeding, but you will simply add new fluid in place of the old) is one example of a job that ECB Invalid Mode can be used for.

    There are also frequent posts where someone will confuse "fluid replacement" with "bleeding" and think there is a way to bleed the brakes properly using ECB Invalid Mode, but there isn't.