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Brake / ((!)) / ABS / VCS

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by TuckerJW, Jul 6, 2024.

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  1. TuckerJW

    TuckerJW New Member

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    About 50,000 miles ago I could hear the pump making a chattering noise that gradually increased in volume and duration in my 2009 Prius. This continued until all of these lights appeared on my dashboard. I read the codes on my dashboard and determined I needed to replace the actuator. After extensive research and preparation. I replaced this part with a used actuator I purchased off of craigslist. After replacing I cleared the codes and the the brakes felt great and the car ran with no issues.

    This past month all the lights returned and a constant beep returned. All this happened with what seemed like no warning. The breaks immediately felt different. They are soft to the touch and my breaking distance has drastically increased making it much harder to come to a stop. While trying to bring the vehicle to a quick stop I can occasionally hear a grinding sound coming from the breaks.

    Codes from techstreams:
    • C0200 - Right Front Wheel Speed Sensor Signal Malfunction
    • C1246 - Malfunction In Master Cylinder Pressure Sensor
    • C1252 - Hydro-Booster Pump Motor Relay Malfunction
    • C1256 - Accumulation Low Pressure Malfunction
    • C1364 - Malfunction In w/c Pressure Sensor
    • C1365 - Malfunction in ACC Pressure Sensor
    • C1391 - Abnormal Leak of ACC Pressure
    About a month prior to this issue I ran the codes for another issue and these are the codes I had for ABS/VSC/Trac:
    • C0200 - Right Front Wheel Speed Sensor Signal Malfunction
    • C1256 - Accumulation Low Pressure Malfunction
    • C1391 - Abnormal Leak of ACC Pressure
    I have read that if the master cylinder has a leak, that the actuator pump will run more often to overcome this leak, causing premature failure at the actuator. I cannot visually see a leak at the master cylinder, and my brake fluid level has not gone down any.

    Given the information I was hoping someone has had a similar issue they have solved or someone would be able to provide guidance to continue my troubleshooting. Thanks in advance.
     
    #1 TuckerJW, Jul 6, 2024
  2. TuckerJW

    TuckerJW New Member

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    Forgot to include that I have visually inspected front and rear breaks and everything looks solid there. Trying to include as much information as I can.
     
    #2 TuckerJW, Jul 8, 2024
  3. Tombukt2

    Tombukt2 Senior Member

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    Very common you'll be doing this repair again this is what happens with used parts I've done this on one vehicle twice once It just happens I can do this in about 2 hours now You don't mention anything about bleeding the brakes or any brouhaha about bleeding the brakes so I'm wondering how was that accomplished but since all the lights were off for a little while I guess it was done well enough to make that happen now with this master cylinder you're dealing with you're seeing what happens when the thing really starts to mess up before you didn't talk about the lengthy stopping distance. Etc But as you see the Prius stops even with the lengthy stopping distance and the no regen breaking etc You see it stops it's just scary because you're not used to driving a car with four-wheel drum brakes no brake booster and things like that this would have been like in the '60s so if you weren't around then you know nothing of this kind of stuff so it scared you to death or what have you some people this probably wouldn't scare very much because well they've been there and done something similar but on purpose Good luck not too bad just the way it goes sometimes.
     
    #3 Tombukt2, Jul 8, 2024
  4. ChapmanF

    ChapmanF Senior Member

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    The leak causing the problem is usually an internal one: the pressurized fluid is just getting past a worn-out valve inside the actuator, and rejoining the unpressurized fluid in the reservoir. It doesn't ever leak out of the system.

    How did you take care of bleeding air from the system when you installed this actuator? The several codes about unexpected readings from pressure sensors I could believe if there was some air left in the system after installation and it eventually made its way to where it affects pressure sensor readings during braking.

    So if there was anything homegrown or iffy about the air bleeding that was originally done, I might try repeating that first, doing it by the book with a suitable scan tool.

    But yeah, if it's not that, it's probably the used actuator.
     
    #4 ChapmanF, Jul 8, 2024
  5. TuckerJW

    TuckerJW New Member

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    Thank you for the response. I I tried to bleed the brakes today with techstreams and I never got any air or fluid to come out the right rear bleeder valve. Does this still sound like its an issue with the actuator?
     
    #5 TuckerJW, Jul 20, 2024
  6. saneesh8

    saneesh8 Junior Member

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    Regarding "I never got any air or fluid to come out the right rear bleeder valve" Can you try the vacuum method? I did the vacuum flush last week. Also somewhere i read that this issue happens when the linear valve adjust is not done in TechStream.

    I have the same car (2009) with 147k on it. The actuator is making noise every few seconds. Don't really know how long it will last.
     
    #6 saneesh8, Jul 23, 2024
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