Warning Lights Came on while driving, did not lose power

I've searched this forum and found many somewhat similar instances, but nothing identical to what I experienced yesterday.

I was driving my 2006 Prius on the highway (120,000 miles on it). I'd been driving about 10 minutes and all of a sudden, the dash warning lights lit up.
Red triangle with exclamation point.
Yellow circle with exclamation point.
Yello check engine.


The car did NOT lose power. It kept driving fine with no noticable change in how it operated. Fuel consumption stayed the same. Braking worked fine. I had a completely full tank of gas (had just filled it up before I got on the highway). Temperature outside about around 60 degrees.

I kept driving to my destination (another 20 miles at highway speeds).

The car sat parked for about 3 hours.

I returned to the car, started it up. The same warning lights appeared, except for the Yellow circle with exclamation point.
Plus, this time I noticed on the energy monitor screen the graphic of the red car with the exclamation point.


Again though, everything seemed to be working fine. While the car had been parked for 3 hours I did some browsing through the owner's manual and saw a notation that is the warning lights were only yellow and not red that it was okay to proceed with caution to the nearest dealer.

That made me decide to chance the drive back home.

I left and started driving home, about 35 miles away, on the highway.

It drove fine the entire way. About 25 miles into the drive home (about 25-40 minutes) the Yellow circle with exclamation point appeared again.

When I got home, I shut the car off. I turned it back on and the Yellow circle with exclamation point did not come on, but the other warning lights did.

I read in the common problems section of this forum the recurring issue of cars losing power and all the same lights coming on:
Problem: Car loses power. Master warning light (red triangle) appears. Brake and VSC lights may appear.
Symptoms: See above
Frequency: After car has been driven for a while, especially in hot weather
Diagnostic: DTC P0A93, Inverter Cooling Performance
Cure: Replace inverter coolant pump
Other information/Alternate diagnosis possible: This is a popular reason for Prius to stop dead, usually in hot summer weather. We've seen a sufficient number of inverter coolant pump failures so I would say that if you have more than 100K miles logged and you wish to keep your car in top condition, consider replacing this pump now as a preventive maintenance move.

However, like I said, I didn't lose power. The car drove fine for about 50 miles at highway speeds and the temperature outside was in the 60's.

What exactly do these lights mean? Why would my car drive fine if there was really a problem?

 

Also, I should note that I had the stock 12V battery changed out for a new Yellow Optima battery about 2 months ago.

 

Odd, the Toyota manual says the exact opposite.
It says it's safe to drive the car to a dealer if the warning lights are yellow and not red. In this case, to get to a dealer I had to drive back to my house, since it's a block away. I figure I might as well research first before a dealer gives me the run around and charges me inflated labor charges.

What do you base your response on?

I don't have a code reader.

 

I drove it to the dealer for the pump recall - they replaced it and that did the trick!