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Prius 2010 C1290 + C1391

Discussion in 'Gen 3 Prius Technical Discussion' started by xILikeRice, Jan 8, 2023.

  1. xILikeRice

    xILikeRice Junior Member

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    The dreadful C1391 code came up on my OBD-II scanner and all the lights relating to the brakes are lighting up (the red 'BRAKE', ABS, and the ((!!))). I'm assuming it's the brake actuator that's broken and needs to be replaced. I was quoted $1900 to get it replaced by a Prius mechanic. I was wondering if it's worth to even fix at this point... It's at 160,000 miles and I don't want to spend more than I have to on this car that I'll probably be driving for another maybe 2 years. Is it fine to still drive it? It still brakes, but it just feels like the brakes of a gas car, and the regenerative braking stopped working too. I wonder also how hard it is to replace it.
     
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  2. Tombukt2

    Tombukt2 Senior Member

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    To people that do a little wrenching it's not a huge job It may seem like it but it's not to me it's not even worth paying them $1,000 for the part but that's just me personally everyone else seems fine with $1,900 brake jobs then a head gasket is probably in your future and it may not make the two years and when you find out what people are talking about doing with that you can read it here You will definitely be not spending any money and wanting another car most people are looking to just insert the key and go this model with that mileage is getting to the point where that's not going to be really a happening believe it and good luck it's not as bad as it sounds but it is the most people
     
  3. xILikeRice

    xILikeRice Junior Member

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    I don't want to risk the chances of my brakes failing on me... I was researching and I saw that some people got away with the problem by only replacing the brake actuator? I was wondering if both the brake booster assembly and the actuator both need to be replaced for it to function again. How can I see which one is the issue? When I start the car, I hear the pump run and stop every 5 seconds
     
  4. Tombukt2

    Tombukt2 Senior Member

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    Sometimes you can take a stethoscope of the mechanics variety they're inexpensive and sometimes you can listen to the individual pieces and listen for the leaks they're internal they'll make noise like leaks If you have leaks in both units they're both going to get replaced If only one unit is leaking down causing the pump to run You might get away with replacing that leaky unit only
     
  5. Mr. F

    Mr. F Active Member

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    If you're hearing the pump running every n seconds without so much as touching the brake pedal, then the actuator assembly (at minimum) is faulty.
    Whether or not the accumulator is also failing can be determined by putting a mechanic's stethoscope to the pressure vessel part of the assembly and listening for a whistling noise.
    Explanation in this post.
     
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  6. xILikeRice

    xILikeRice Junior Member

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    Thank you! Just to make sure, the actuator is also known as the brake master cylinder, right? If that's the case, is it reasonable to just replace only the master cylinder and leave the accumulator alone? What are the odds that both malfunctioned at the same time?
     
  7. ChapmanF

    ChapmanF Senior Member

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    The odds that both malfunctioned at the same time are really low.

    On the other hand, suppose the actuator has malfunctioned, so that the pump has to run every 5 seconds, and the car has been driven around like that for some weeks or months, as people sometimes do. A week at every 5 seconds may be like a year or two in the typical life of a pump. So even though they might not have malfunctioned at the same time, the pump could be getting extra worn too.