Need Warning Light assessment

It is really easy to check the inverter coolant pump. Make the Prius READY, open the hood and look at the inverter coolant reservoir for fluid turbulence. If you see this, the pump is working. If you don't, then the pump is not working and the car should not be driven.

If you need to retrieve the DTC as a DIY project, get Mini VCI.

 

Alas it's not that simple.
Each light can come on for a multitude of conditions.
You need to retrieve the stored failure codes to make a better "guess" at what is really wrong.

Note: If your 12 V battery is over 5 years old, IT might be the cause.
If it is the original OEM battery (~9 years old), you should get a new one before chasing a phantom failure.

P.S. Call a few independent shops. The Prius has been around long enough now that a good independent should be able to read the codes, test the battery and at least give you a partly-educated guess.

 

A couple of years ago I had a whole bunch of warning lights come on when I was stopped at a stop light. The brake pedal became firm. It was clear that the power brakes were not working correctly. I drove home VERY CAREFULLY and parked the car. I could not find a garage to look at it until the next day. When I started my car the next day to take it into the garage -- no warning lights. The garage determined that there was a fault somewhere in the front, left braking system, but they did not have the software to go any further. (They explained to me that the more detailed software costs considerably more.) It's been over two years and another 30K miles with no more warning light show. "Your mileage may vary."