Is the red triangle bright red, or a dim visual of triangle?

The red triangle of death is very bright. Never seen a dim one. But dim or not it’s probably still a triangle.

Triangle can mean a few things are bad but whatever thing is bad it’s a fatal flaw and must be fixed.

may be hybrid battery or failed inverter pump or failed abs pump.

Most common is failed inverter coolant pump. Easy to determine just start the car and then take the cap off the inverter coolant reservoir look carefully in there with a flashlight and if the fluid is just sitting there not moving the pump has failed.

If coolant moving it’s probably the hybrid battery. If it has the little red car icon inthe upper corner of the mfd it’s the hybrid battery. Not surprising it’s a very low mileage car that kills the hybrid battery just like it killed mine.

The hybrid battery has a few different ways it can fail. One very common is a high voltage ground fault. It can be temporarily reset by disconnecting the 12 volt battery. If it fixes the red triangle and car is then drivable it has a ground fault failure.
This is from bad corrosion or leaking electrolyte from one of the battery modules.

Your just resetting the fault. It will come right back on after driving a while.

Use the search forum link up top and search

hybrid battery.

 

It should be bright enough to notice it while driving, could it be the dash brightness is turned down or the angle of the winter sunlight?

Regardless, if you have warning lights displayed on the dash, then generally you will have OBD2 codes (DTCs) stored in the ECUs.

Visit each of the local auto part shops for a free OBD2 code scan, record the findings, then post the DTCs here for additional guidance.

How old in the 12v battery, and when did you last check the engine oil level?

 

In my car, if the sun is bright and shining in the windshield at a certain angle, one or more of the warning lights appear to be dimly lit, including the triangle. They are not lit. It is an illusion.

 

As others have suggested, a "dim visual of the triangle" suggests only that you have managed to see where the triangle is located in the dash cluster, and it isn't lighting up. No worries.

In case it ever does light up in the future, it will be helpful to know that it doesn't mean "hybrid battery is about to go". It is called the "master warning light" and there are about 200 reasons it can come on. Some are major deals and some are minor deals. The best response if it ever does light up is just to remain calm and get the trouble codes that are being reported.

 

As mentioned, the "master warning icon" can show up on the MFD (A/C-radio screen) when there is on of many system faults (with codes). However there are also a couple things that can trigger it without codes- such as having lack of oil pressure (often due to low oil level).

Posted via the PriusChat mobile app.

 

I would start logging some miles on that car go somewhere make something up.LOL

 

he is incorrect. if he checks and there are no codes, it isn't setting the triangle. ir there are codes, the trianfle light must be loose or defective in some way.

many report a rapidly fluctuating battery gauge when the battery is getting weak

 

It seems like owners new to a Prius often get a kind of tunnel vision about the battery. The car is a car, with a lot of the usual car things to think about and maintain, and while it's possible the battery conks out while you own it, it's also possible that some ordinary sequence of ordinary car things—wheel bearings, brake parts, electrical connections, whatever, perhaps even a collision that ends your use of it—could all come and go without you ever seeing the much-fretted-about battery failure.

That was the way it went with my Gen 1, which was still on its fifteen-year-old original battery when my use of it ended.

 

This mechanic is incorrect at best, and it takes only a couple of minutes to check the OBD2 codes (DTCs), even when busy. Unless it was the low oil level that caused the warning light, there should be stored OBD2 codes in the ECUs (try all of the auto parts store in the area).