Gasoline-only mode, what is it called

About a month ago, I was driving on the freeway in 2006 Prius at around 4pm and a bunch of warning lights (including yellow triangle) came on and the car lost some power. I pulled off the road and checked manual, which basically said that I could drive the car to dealer UNLESS the brake light was on, in which case I should have it towed.

I got back on freeway and quickly noticed that there was a terrible lack of ability to accelerate and the engine sounded as if it was running very hard (or maybe it was just the cooling fan), so I got off the freeway and took surface streets to the dealer. It was only about 4 miles remaining, but with heavy traffic and I could barely get across uphill intersections before the light changed. It was a very hot day (about 105 degrees F) and I opened all the windows so as not to have run the AC, which was just blowing hot air anyway. It was quite an ordeal, and the trip took about 45 minutes to cover 5 miles, which would have been 10 minutes on the freeway.

I finally got to dealer and they later determined the HV battery had failed. They also replaced the inverter pump under voluntary recall. A few days later they also needed to replace a relay, and I insisted that 12V battery be replaced also. Now my car seems to run better than ever.

But I'm a little worried that my trip to the dealer apparently with only gasoline power may not have been good. The engine did seem to be revving very hard. I'm wondering if I could have foamed the transaxle fluid, put stress on engine cooling hoses, that sort of thing. My 80,000 mile service is coming due, and I'm thinking of asking them to check for possible damage, or maybe even change transaxle fluid as a precautionary measure.

But I barely know how to investigate this situation because I don't know what it is called. The Dealer said I had used "failsafe" mode, but that now appears to be a description of the failsafe braking feature.

 

Please answer question, is there a name for running with dead HV battery, a name like "failsafe mode". If I know the name I can easily search for others having same problem. They never told me the error codes.

Prior to the breakdown, I noticed the battery was always discharged in the morning, after becoming fully charged at night. I was planning to have dealer check it out the following week. All repair work including replacement of HV battery was done at no cost to me, and I also got 3 weeks of free car rental (two breakdowns and waiting for parts) and free towing. I'm not sure what part of that was covered by standard warranty and what part by Toyota Platinum extended warranty, and since it was all covered I didn't ask. I thought the HV battery was covered to 7 years 100,000 miles in Texas (more in California). I paid for 12V battery myself because they didn't think there was anything wrong with it.

There has been no sign of anything wrong with engine ever. But when HV battery went out and I was continuing on to dealer with all the warning lights, it seemed like the engine was revving very high. Or maybe it was just that the cooling fan was running very high. It was that kind of sound, like a cooling fan running very high. No roughness at all.

Perhaps I remember incorrectly about the AC. I shut it off, fearing it would add to difficulty. But I thought I noticed just before shutting off that it was blowing warm, and I figured AC compressor wouldn't run with dead HV battery since it is powered by HV battery. It's worked perfectly after HV battery replacement.

 

OK, thanks, I checked the receipt, and in fact it does list the error codes under which the HV battery was replaced:

PA80 and P3019. It also notes check engine light and VSC trac light.

So what would would you call this driving mode?

And what would have been the wear-and-tear on the engine and transaxle as I was limping to the dealer in heavy traffic for 45 minutes on a 105 degree day? Like I said, it seemed like either engine or engine cooling fan was running at high speed, and I fearing disaster at any moment.

 

[repost?] I see now the error codes are listed on the receipt: PA80 and P3019. It also mentions check engine and vsc trak light on.

So what kind of stress would driving under these conditions put on gasoline engine and transaxle? It seemed like either engine and/or cooling fan was running very high, and it took a minute to accelerate through uphill intersections. It was 105 degrees and I needed to drive for 40 minutes through heavy street traffic to get to dealership.

 

PA80 is what the receipt says, so I'll have to ask the service manager next time what the real code was. BTW, the battery part number is G9510-47031. That's a whole new battery assembly, right?