05 Prius with Red Triangle, VSC and brake warning lights on

Check for turbulence in your inverter coolant reservoir. Open up the cap and see if there's swirls/movements in the water while the car is on.

A more common failure now is the inverter pump, fails around 100k miles

 

...'nother poss
Brake Actuator Assem - Warranty Enhancement | PriusChat

 

Best way is with a minivci that includes Toyota's techstream software installed on a Windows laptop running XP or a 32 bit version of Windows 7. They can be had for under $20 on Amazon. There are also phone apps, but you have to install the PID codes on your phone to read them all. Here are a few to choose from:
https://www.amazon.com/mini-vci-techstream/s?ie=UTF8&page=1&rh=i%3Aaps%2Ck%3Amini%20vci%20techstream

 

The 12V battery could be a problem, and your car might have more than one issue.

The voltage dropped down to 13.2V because the battery reached full charge. However since you still have the red triangle, another problem is present.

Have you checked all engine compartment fluids, especially engine oil level? Did you perform the check suggested in post 2?

 

It could be anything from a bad hv battery, car overheating, bad sensors, it's anybody's guess at this point. You need to get the codes read

 

sounds good. and when the lights come back on, get a prius aware code reader.

 

How did you clear the red triangle? My 05 is doing the same thing. I’ve been to Toyota 3 times in the past 3 months...$2300 later I have no idea what’s causing this triangle alert. Is there a way to clear it?

 

1) The info/codes displayed on the MFD are only for audio, navigation. Stop wasting your time playing with it, unless you are experiencing issues with the audio/navigation system.

2) Toyota should have given you the codes and cleared the codes after every visit. You were not provided with an invoice showing the codes and amount you paid to fix the problem?

3) It could coincidently be that after each visit a different problem arose, which was not present during the initial visit. But, since you keep saying Toyota found nothing, possibly incompetence at the dealer?

4) Go to another dealership or an independent shop that ideally uses Techstream software to retrieve Toyota/Lexus codes.

5) You did not say you ruled out an inverter water pump issue and low engine oil level? While at it, check the other fluid levels too. Checking the engine radiator coolant level involves removing the big black plastic cover that spans the width of the engine compartment, and is held in by six (?) plastic phillips fastness; checking the coolant fluid overflow bottle is not good enough, you must remove the radiaator cap and verify taht the fluid is near the top when the radiator cap is removed. You check the radiator level WHEN THE ENGINE IS COLD; check after the car has sat overnight to be guaranteed a cold engine, and no residual pressure.