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Red triangle going downhill

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by ChrisP60, Aug 7, 2024 at 9:02 PM.

  1. ChrisP60

    ChrisP60 New Member

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    my Prius has done 120,000 miles.
    A red triangle with an exclamation mark (!) appears sporadically on the dash – with a beeping sound.
    I have taken it to a garage and they told me that no specific error code is showing.
    They have checked things like the oil level and say that it's fine. There is plenty of tread on the tyres.
    The red triangle appears when...
    * I drive down a hill at 50mph and I've taken my foot off the gas pedal.
    * I go round some corners.
    * When I drive up a shallow ramp to a freeway and there's a slight tilt downwards of the road to the left.
    The red triangle can appear several times during a 10-minute journey and it has become more frequent over recent weeks.
    I'd love to know your thoughts... and also thoughts on the garage that couldn't find the issue!
    Thanks!
     
  2. JC91006

    JC91006 Senior Member

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    bring it to another garage with the proper equipment to read the codes on a prius. are the tires the same size?
     
  3. Tombukt2

    Tombukt2 Senior Member

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    To be honest to me it seems like you're low on oil up inclines around turns spirited driving etc with not quite enough oil in the car can make that light bounce on and off also in this model coolant issues can cause the same problem The coolant is more tricky to track down so with your car warm you get out of the car you have to have that silly piece of plastic that covers your radiator cap and your fans removed so take that off get the car warmed up get back in the driveway crack the radiator cap just enough to blow off the air you'll hear the air noise You might see a few drops of coolant run down the side of the radiator neck once the pressure is vented remove the cap If you don't see radiator fluid at the very top of the filler neck something's going on so now you take a bottle of water or red coolant and you start adding some to the filler neck and when it comes up to the very top of the filler neck you stop pouring. Now you watch the level of the filler neck you all of a sudden see some air bubbles plop plop and that coolant vanish is down into the radiator and you can't see it pour some more in do this until that stops and the level stays at the very top of the filler neck right at that hole where it's going to drop in and go to the reservoir this may take over a quart of coolant to get you to that level I have a car that does this every 8 days No one can find the coolant. If I leave it longer than 8 days when I'm driving down the road I start seeing the triangle Go on and off and on and off when I see this on my '09 when I get home I do repeat the steps above for filling the radiator I always add close to a quart and then I close it off drive another 8 to 10 days No one has been able to find where the coolant is going I work on my car's extensively I can't find any leaks I don't see it burning up internally I never have any misfire codes or anything like that for any coolant leaking into the cylinders so on and so forth there may be a microscopic leak in a hose or the radiator but I'll be darned if we can find it and I'm pretty good at finding this stuff I'm not willing to just replace all the hoses and rubber just because most of it looks pretty new and and pretty good shape and not becoming permeated or destroyed so they stay they all pump up to pressure nicely The car warms up well etc check those things and see what you got I'm betting on the coolant.
     
  4. ericbecky

    ericbecky Hybrid Battery Hero

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    You are dangerously low on oil!
    Stop driving immediately.
    Check you oil level an post a picture of your dipstick here.
    Buy 2-3 quarts to refill as needed. You may even need more.
     
  5. ChrisP60

    ChrisP60 New Member

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    Thank you, Eric. I went to the garage today with a printed sheet of your words and those of the other people here. The senior guy there said the team had checked the oil etc and it was all fine. But almost to humour me he said he'd check it again... and you were right: the oil was super low and he put about 4 litres in: 7 pints! I drove the car after that and... no red triangle. So thank you again for saving my bacon.
     
  6. ChrisP60

    ChrisP60 New Member

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    Hi Tom, I don't know if you'll see what I wrote to Eric, so let me repeat it here... I went to the garage today with a printed sheet of your words and those of the other people here. The senior guy there said the team had checked the oil etc and it was all fine. But almost to humour me he said he'd check it again... and you were right: the oil was super low and he put about 4 litres in: 7 pints! I drove the car after that and... no red triangle. So thank you for saving my bacon.
     
  7. ericbecky

    ericbecky Hybrid Battery Hero

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    Guess they previously Didn't check the oil.
    Glad to hear you engine didn't get destroyed.

    The symptoms you described were classic signs of DANGEROUSLY LOW oil.
     
  8. V Sport Wagon

    V Sport Wagon Member

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    Just the red triangle alone could mean failing Hybrid system, Brakes, Electrical, anything critical of importance. To simply say it means "oil level low" is wrong. There's an oil can light (yellow) that will flash or come on intermittently when the pressure and level drops below the sensor. (during similar driving situations like you described).. I've never seen the triangle for oil being low. At that point it should have already thrown a rod through the block.