Inverter cooling problem?

I have a 2010 Prius that I have owned since 2013. It had 32,000 miles when I got it, and it has just under 90,000 now. We have had no problems with it until two weeks ago. We were driving to my son's HS graduation on a 100-degree day when it suddenly lost power with just enough power to pull off the road. It displayed the check hybrid system error. I found that if we reset it, by removing the battery pack safety thing, and the white auxiliary battery cable from the fuse box for 10 minutes and replacing we could get it to drive on battery power for about 30 seconds before it would shut down again. It was pulling the p0a94 and p0a1a codes. I had it towed home, and did my research, and found it was most due to the inverter burning out. The inverter coolant was about a half-inch below the low mark (my bad) and the codes were inverter related.

I figured that rather than have the dealer charge me $500 just to diagnose, that I would gamble on a salvage inverter for $183 off ebay. I ordered one that they said was tested and had a 6-month warranty, drained the coolant, removed the battery pack safety plug, disconnected the auxiliary battery and removed the old inverter then waited a week for the new one to arrive. The new one came, and I replaced it, refilled the coolant and plugged the batteries back in. I powered the Prius on , cleared the codes and it started right up. I drove it 26 miles on various roads with no issues and told my wife she could drive it to work on Monday. She normally drives this car and her work is one mile away. She called me Monday and told me the check hybrid system error came back but it drove no problem and she was able to drive it to work. I drove to her work and swapped her cars, and drove it the one mile home with no problems other than the error. I checked the codes and found that it was pulling the same p0a94 and p0a1a codes, but the car runs fine. I think there is a problem with the cooling system that caused the original inverter to fail and this one to get hot enough to trip the code. I think it may be the fan since, in all of my driving, I can't remember ever hearing the fans come on. I don't drive this car much so I can't remember how loud the fans get. The fan fuse seems to be OK. The coolant is at the full mark. Should I look at replacing the fan, or swapping out that inverter on the warranty? Is there a way to test the fan? I think I read somewhere that it always comes on if you turn the AC on? The fan isn't coming on with the AC on mine.

I know that there is a recall on the inverter on these. I don't want to deal with the hassle of the dealer. Having them talk me into buying a new car, or paying them 3 grand to replace the battery pack and whatever else they can find. We like this Prius. We want to replace the battery pack with one of those projectlithium Lithium-Ion packs and try to get another 10 years out of this one. It only has 90,000 miles on it.


If there is a recall inverter part number, I would rather just buy a salvage one and replace it myself. I really think this is more cooling-related anyway but I am interested in hearing other thoughts.

 

Unfortunately, I cleared out the codes on Monday when I got it home. In hindsight that was a dumb thing to do because my wife's place of employment is maybe 100 yards from an Autozone and I could have had AutoZone check it with the better scan tool. I was wondering if maybe there was just an air bubble in the inverter cooling system so last night I completely drained it again, and refilled it with brand new coolant ensuring that I powered the car on a few times to let the coolant circulate and get the air bubbles out and add more coolant as needed. Today, I let it idle for a half-hour with the AC on full. It did not generate the error codes again, but I was able to confirm that the cooling fans are definitely running. I think what I am going to do is trade my wife cars for a couple of weeks and drive the Prius to work just to make sure everything is good. If I get another error code, I will pull the codes with a better scan tool.