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Dash lights came on but still drives

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by ChrisDG, Oct 1, 2020.

  1. ChrisDG

    ChrisDG New Member

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    2006 Prius
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    Two
  2. edthefox5

    edthefox5 Senior Member

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    It’s the red triangle of death the RTOD. It means the car has seen something fatal pull over and open the hood and look.

    Usually these days it’s the hybrid battery failing. Whatever it is it may leave you stranded. Stop driving it till you knowl

    It has codes stored you use a hybrid capable obd code reader and it will tell you what it’s unhappy about

    Dealer charges $125 to pull codes. Get the codes read in writing the full 7 digit codes and post it back here.
     
  3. Isaac Zachary

    Isaac Zachary Senior Member

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    I think my Red Triangle will come on if the doors are open while I'm driving, or if maybe the keyfob battery goes dead. Definitely check those first. But that light, along with the little yellow engine light and the brake light, as @edthefox5 said, usually mean there's a major problem with some part of the car.

    One time that those lights came on in my Prius it was because the hybrid battery was having a major problem due to a cell that had died. That's my guess as to what your problem likely is, but like @edthefox5 said, it could be anything major. And we won't know for sure unless you either get the codes read (easy way) or test each part that could be the problem (very hard way).

    When it happened to me I also noticed the car didn't have the same kind of power it normally does. That's called "limp mode." The car will drive, but only enough for you to limp it along to somewhere safe. At any moment it could become undriveable, so don't move it unless you have to. Mine, at one point, died on the highway and I had to coast over to the shoulder and wait for help.

    To diagnose the problem I got the codes read with my own code reading solution (an OBD II to Bluetooth adapter and the Torque Pro app on my Android phone.) I compared the codes to what I researched online and found that one pointed to the Hybrid Battery needing to be replaced and the other saying that block 11 in the Hybrid Battery was weak.

    I replaced the module containing the dead cell in block 11 with a used module and now am gearing up to replace the whole battery before another cell dies. For now those lights have all gone away for me.
     
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  4. ChapmanF

    ChapmanF Senior Member

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    The master warning light, which many insist on calling the triangle of deeeeeaaaaaatthhhh, comes on whenever the computer that coordinates most of the car's operations has something it would like to tell you.

    Sometimes what it wants to tell you will turn out to involve a serious or expensive problem. Sometimes it will mean that some trivial recalibration or similar procedure needs to be done. Sometimes it means there is a minor electrical issue to be tracked down.

    The key is to plug in to the diagnostic port and ask it what it wants to tell you. There are a couple hundred possibilities; that's a wide enough field that just guessing, or asking other people whose master warning light came on what the problem was for them, isn't a sure way to get anywhere.
     
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  5. TMR-JWAP

    TMR-JWAP Senior Member

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    Here we go...

    Assuming it's a P0A80 code, because your indications are exactly what one gets when that code triggers (but those symptoms can also be from several other things)

    A P0A80 code "replace Hybrid Battery" will trigger when certain conditions are met that show HV battery degradation has or is occurring. A P0A80 code, when by itself, will allow normal driving to continue. At some point, whether 5 minutes, 5 days or 5 weeks from now, an additional code will trigger, providing more details about the problem. That is usually a P301x or P302x, which will designate which pair of the 28 individual modules is causing the problem. At the point this second code triggers, the car will shift to 'limp' mode and will act similar to a standard ICE car that has a slipping automatic transmission. The engine will rev, acceleration will be poor, etc. Having a scan tool available to read and reset the codes will return the car to normal operation until the codes trigger again. As time passes, the codes will trigger more and more frequently.

    As mentioned above, the only real way to diagnose is to.....get a diagnostic code evaluation.
     
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