Red triangle going downhill

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

 

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.