Dealership being vague about inverter problem

Recently, I had my hybrid system warning light (along with the big red triangle, the (!), and VSC) come on for about a day on my 2005 Prius, and I made an appointment for maintenance at my local Toyota dealership to have it checked out. As luck would have it, the warning lights weren't on the day that I actually took it in, and they said they had a hard time digging up any codes that pointed them in the right direction, but the best answer they could give me was that my inverter was "starting to fail." (According to my bill, they pulled up POA08).

I did a little bit of researching, and I'm just not very satisfied with their answer and I'm growing less confident that they looked very hard for the issue. From what I've gathered, a major reason that inverters fail is due to overheating, but he didn't specify if they checked the pump, the coolant channel, etc. All he said was that the cost of replacing the inverter would total my car, so I was better off just driving it until it failed for real, since my car still seems to be running normally.

My warning lights have since all come back on, and for 2 days straight this time, but I'm wondering if it's really worth spending the diagnostic fee again to get another vague, unhelpful answer. Is there any value in going back with the warning lights on? Will that help them localize the issue? Is he right, and I should just continue to drive my car?

Some additional info: I've checked my inverter fluid pump myself, and while there is some turbulence, I'm not sure how much is "normal" and if mine is still perhaps going bad. I know there was a recall a couple years back, but I didn't have mine checked out then, and punching in my VIN number on Toyota's recall website doesn't bring up any results. Again, I was hoping this was something that would have been checked when I went in, but I'm just not confident that that was the case.

Even more info: car is at about 170,000 miles right now.

Thanks in advance for any insight.

 

So if it is a failed battery, am I safe to still be driving it? Right now, it drives normally from what both I and the mechanics at the dealership who drove it a while could tell. I've been limiting myself to short trips to commute to classes everyday, but I had a 5-hour drive planned to visit the SO next weekend, and I'm wondering if it's unwise to think it will make the trip.

Also, the code they pulled up was P0A08, not P0A80.

 

I just had my 12 V battery replaced a couple months ago by this same dealer and haven't had any issues prior to this point. The state of charge has not been fluctuating, and I have not noticed the fan by the back seat come on. That used to happen a lot years ago, but it's been some time.

I did get rear ended a couple of weeks ago; not sure if that could have knocked something loose on the 12 V batter since it's back there? But the symptoms seem awfully delayed, if that's the case.

 

Honestly, my symptoms are nearly identical to this thread (Weird, intermittent indicator lamps (VSC, Battery, Triangle of Doom, "(!)", and Hybrid System) P0A08 | PriusChat), which is a bit discouraging, since it sounds like they didn't resolve the problem even when they did replace their inverter.

 

Could you direct me to a source where I might find out how to do that? Does it require accessing the 12V battery in the back of the car, or just inspecting the terminals under the hood?

 

Thanks. The voltage readings were normal. Is a failing inverter something that could be intermittent, causing the voltage to look normal depending on when I happened to measure it? I just want to make sure I can safely rule it out with one reading, or if I need to take multiple readings to be confident that it's not the inverter itself.

 

Would a bad 12V battery also cause the charging system warning light to come on? That has recently been added to my fun sporadic warning lights. The strange thing is that my regenerative braking seems to be working fine, and the HV battery seems to be charging fine as well, according to the master display. What else in the charging system could cause that light to come on, in addition to the others? Could the dealer be right about the inverter failing, then?

 

Voltmeter reading at READY with the warning lights on was 11.9 V, if I recall correctly from this morning when I checked. Definitely below 12 V, though. It jumped to 13.7 V once the car was totally running.