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How can I see in Techstream what is causing red triangle?

Discussion in 'Gen 2 Prius Technical Discussion' started by Bravotango, Apr 28, 2020.

  1. Bravotango

    Bravotango Junior Member

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    Hi all, of course searching "techstream cause red triangle" has numerous code specific threads but, I can't see how in TS I can see exactly what is causing RTOD. I am getting P3000-123 and swapped packs and still getting same code but not sure if that is the cause as I have some other ones. And of course, oil is good :)
     
  2. ChapmanF

    ChapmanF Senior Member

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    Há Ži,

    The repair manual (more info) is the best source for what the codes mean. P3000-123 can't be the only trouble code you have, because it is only a code that the hybrid-vehicle ECU sets to tell you to go look at the codes from the battery ECU.

    When you tell Techstream to do a health check, if it is reporting a P3000 from the HV ECU, there should also be a code (or more than one) showing for the battery ECU. It would be weird if there isn't. If there isn't, you should at least go directly to the battery ECU screen and see what information you can get there. If it isn't possible to get any, possibly the battery ECU itself has gone south.
     
  3. Bravotango

    Bravotango Junior Member

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    Thanks Chapman. I do have other codes yes and I can study each code but my question is, how can we see a chart that shows what codes will generate a red triangle? In other words, I doubt my AC code will throw a RTOD so I'll ignore those but of the codes I have, I want to tackle, for now, only the one(s) causing the RTOD. Is there a list somewhere?
     
  4. ChapmanF

    ChapmanF Senior Member

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    RTOD or "red triangle of death" is a dumb name that everybody keeps using no matter how insanely misleading it is.

    The light is called the "master warning light" and it comes on pretty much to alert you about any warning condition that the HV ECU would know about. People would make way fewer unhinged assumptions if we called it something more proportionate, like "the red triangle of if you would sir, when it's not too much trouble, you might retrieve some codes that could be worthy of your attention."

    It also happens that, because the dozen or so computers in the car talk to each other, a lot of conditions will end up being things the HV ECU knows about, even if some other ECU was the first to detect them. And the MWL will light up.

    The best place for that information is the repair manual. If you're not looking there yet, at least make note of which ECUs are the sources of the codes you have. Your P3000-123, for example, is a code from the HV ECU (that's the one that's in charge of the MWL). The meaning of P3000-123 is "I am lighting the MWL because the battery ECU told me it has codes you need to check."

    Based on that, my next area of focus would be on any codes from the battery ECU.
     
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  5. Bravotango

    Bravotango Junior Member

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    Master Warning Light- got it. The P3000-123 in the manual says: Abnormal signal input from battery ECU (HV battery system malfunction). I swapped packs with different ECU's so odd to get the same code for both packs but, I can swap in a third ECU in the pack and try that. Also, fwiw, I got the manual pdf chapters from this link after trying several Toyota Prius 2003-2009 Service Repair Manual | Cardiagn.com

    Thanks ChapmanF

    It would still be good to know what codes set off the MWL if anyone has a list. I know low oil does :)
     
  6. dolj

    dolj Senior Member

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    It would be a pretty long list, and I'm not sure how you think it would help you. But if you insist on looking at it, it is in the repair manual. It is just not a collated list, rather interspersed with all the codes.

    I think you're missing ChapmanF's point, though, you need to read the code(s) from the battery ECU. They are the ones that will be of most informative.
     
    #6 dolj, Apr 29, 2020
    Last edited: Apr 29, 2020
  7. ChapmanF

    ChapmanF Senior Member

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    Well, the P3000 code has been read from the HV ECU. But what it means is to read the codes from the battery ECU. Continuing to swap the battery ECU without looking at what it is telling you is like shooting two or three messengers in a row with no attention to the message they are bringing.

    As already mentioned, the HV ECU lights the master warning light when it is aware of a warning. That includes warnings it detects itself and those reported to it by other ECUs. (The oil pressure switch, for example, is connected to the engine's ECU.) That's a lot of codes, and they're all in the repair manual.

    It's not clear how interesting some kind of condensed list of "codes that light the MWL" would be; if your MWL is on, you obviously have at least one such code, and will have to read them and look up what they mean anyway, and that will tell you what you need to know.