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VSC, ABS, (!), emergency brake light on

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by ascensionist, Nov 2, 2020.

  1. ascensionist

    ascensionist Junior Member

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    Have a 2008 Prius. I've fixed many problems over the years; however, I'm finally stumped.
    My VSC, ABS, (!) and emergency brake light are on and cannot figure out why. I searched this forum for answers, but have not found a thread that exactly represents my issue.

    My initial thought was starter battery; however, the starter battery I replaced in April 2020. Tested its voltage: nominal voltage of 12.6; 12.1 under load. I went so far as pulling the battery and charging it (so I could ensure that it was 100% charged), and then reinstalling it--made no difference.

    What perplexes me is the vehicle has thrown no codes and runs fine (as far as I can tell): no decrease in functionality; gas mileage normal. One thread I read which described similar symptoms indicated the problem had be found to be the IG1 relay; I changed this just to see it might make a difference; it didn't.

    Thoughts? I am thoroughly stumped (particularly there being no codes to give me a better clue of things to explore.).

    Thank you!
     
    #1 ascensionist, Nov 2, 2020
  2. SFO

    SFO Senior Member

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    How many miles on the vehicle, and which make/model/app are you using to read the OBD2 codes (DTCs) with?

    Generally speaking, if there are warning lights displayed on the dash then there are OBD2 codes stored in the computers (ECUs).
     
    #2 SFO, Nov 2, 2020
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  3. ascensionist

    ascensionist Junior Member

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    A bit more than 200K miles. Replaced the hybrid battery this past April.
     
    #3 ascensionist, Nov 2, 2020
  4. ascensionist

    ascensionist Junior Member

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    This is my code reader:

     
    #4 ascensionist, Nov 2, 2020
  5. mr_guy_mann

    mr_guy_mann Senior Member

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    Usually if there are warning lights on then some module somewhere will have a code.
    Many Prius owners opt for a pirated copy of the OE Techstream scantool software with a miniVCI interface cable from ebay or amazon. Install it on an old windows laptop and you can access all available modules on the car. Most aftermarket scanners or apps don't have the same coverage.

    Side note, have you checked the level in the brake system? Some cars can set no-code warnings if the fluid is low.

    Posted via the PriusChat mobile app.
     
    #5 mr_guy_mann, Nov 3, 2020
  6. SFO

    SFO Senior Member

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    The image or link doesn't appear for me. For images, just copy (control-C) and then paste directly in the posting (control-V).

    ANCEL AD530 Vehicle OBD2 Scanner Car Code Reader Diagnostic Scan Tool with Enhanced Code Definition and Upgraded Graphing Battery Status

    [​IMG]

    Has the above scanner worked for you in the past, and which OBD2 codes (DTCs) did it retrieve?

    It could be that the above scanner isn't fully compatible with a toyota hybrid, maybe try a free scan at an auto parts chain or two.
     
    #6 SFO, Nov 3, 2020
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  7. ascensionist

    ascensionist Junior Member

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    Yes, this scanner has worked very well in the past--never had it not read codes.

    I checked the brake fluid--was a bit low (but this within acceptable tolerance; filled it up anyway--no change).
     
    #7 ascensionist, Nov 3, 2020
  8. ascensionist

    ascensionist Junior Member

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    Scanned again this evening; got two codes: P1121, and P1122. Any thoughts why/how these codes could be related to all these warning lights being illuminated?
     
    #8 ascensionist, Nov 7, 2020
  9. SFO

    SFO Senior Member

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    Here is the workup for DTC P1121 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/repair%20manual/04pruisr/05/2054m/cip1121a.pdf

    Here is the workup for DTC P1122 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/repair%20manual/04pruisr/05/2054m/cip1120a.pdf
     
    #9 SFO, Nov 7, 2020
  10. ascensionist

    ascensionist Junior Member

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    Thanks for this. I'll investigate further. Do you think either of these two codes could lead to the all the light being illuminated?
     
    #10 ascensionist, Nov 7, 2020
  11. dolj

    dolj Senior Member

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    My opinion, I think these two codes only account for the MIL (aka CEL; aka Check Engine Light); You also have at least one each VSC, ABS and, Brake ECU codes.
     
    #11 dolj, Nov 8, 2020
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