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What kind of signal does a 2010 brake fluid reservoir put out?

Discussion in 'Gen 3 Prius Technical Discussion' started by Mike72903, Oct 31, 2023.

  1. Mike72903

    Mike72903 Junior Member

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    2009 Prius
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    Four
    Been getting an error telling me there’s a problem with the brake fluid reservoir. I assume it’s the sensor. Chat GPT informs me it isn’t just a switch but a level sensor that outputs a variable voltage or resistance. It won’t specify which. Anyone know which one of the two possibilities it is and what value would be normal? I’ll check with a VOM tomorrow. Thought I’d check before ordering a new reservoir.
     
    #1 Mike72903, Oct 31, 2023
  2. Mr. F

    Mr. F Active Member

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    Vehicle:
    2010 Prius
    Model:
    IV
    With the vehicle powered off, the output of the reservoir level warning switch is a resistance:
    • 1.84-2.16 kΩ when the fluid level is above the horizontal seam that runs around the reservoir, and
    • <1 Ω when the fluid level is at or below the MIN line.
    What code are you seeing? If it is C1202, it might be something as simple as an open or short in the wiring harness that connects the reservoir level warning switch to the skid control ECU, so I would definitely recommend ruling those out (or, better yet, following the repair manual troubleshooting steps for the specific code you're seeing) before you invest in a part that may turn out to not have been faulty after all.
     
    #2 Mr. F, Nov 1, 2023
    Last edited: Nov 1, 2023
  3. Mike72903

    Mike72903 Junior Member

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    Thanks Mr. F. Very helpful. May I ask where I can find online a copy of the repair manual you mentioned?
     
    #3 Mike72903, Nov 1, 2023
  4. ChapmanF

    ChapmanF Senior Member

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    We have a wiki page with that information:

    Toyota Service Information and Where To Find It | PriusChat

    ChatGPT is a system that has been trained by reading a whole lot of text about a whole lot of things, and is able to write some text that will resemble the text it has been trained on. It is not a system that knows anything about how your car works.
     
    #4 ChapmanF, Nov 1, 2023
    Mr. F likes this.
  5. Mike72903

    Mike72903 Junior Member

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    Location:
    Fort Smith, Ar
    Vehicle:
    2009 Prius
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    Four
    Mr. F thanks again for your excellent advice. My resistance reading was lower than the specs you quoted. All the wiring looked solid. I finally figured out the anti skid ECU was part of the actuator.. I removed the connector that locks in place on the actuator, reconnected it and all the warning lights cleared. Hopefully it remains like that.
     
    #5 Mike72903, Nov 2, 2023
  6. Hookitlow

    Hookitlow Junior Member

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    Location:
    Highland NY
    Vehicle:
    2010 Prius
    Model:
    II
    Any chance you can send me a picture of that connection location? I’m running into an issue with a C1202 now. Replaced the reservoir and fluid, just did the LR hub as that was throwing a code a few days prior, and has been an issue in the past.
     
    #6 Hookitlow, Feb 26, 2024
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