2012 Prius V Five with tech, 370k miles, mostly highway. Purchased in 2019 with 67k miles, one owner with perfect dealership service records. One head gasket down, otherwise normal timely maintenance including EGR cleaning post head gasket replacement. She's been a dream through and through, and if this is the end she's earned her rest - but I'm hoping this isn't her death knell. The 12v battery (from 2021) died recently, when the overhead light was inadvertently left on for several days. I also replaced the cabin air filter, which had apparently (?) been installed upside down and also had a pile of fuzz on top. Replacing it changed how often and how long an unknown fan comes on under the hood - from ~15sec off / 30sec on to ~30sec off / <10sec on. I still think that seems like a lot but I can't say I ever really noticed at speed, but I'm doing a good bit more in-town lately. Anyway, today I sat for about an hour in 90f with the AC cranked, when the engine (?) briefly made a terrible clanking noise so I turned it off immediately. It turned on fine and quiet, I turned it off and packed up my stuff and went to leave. Lots of lights lit up on the dash, lights I've never seen before. I'll try to attach the pic. It did drive, so I brought it to shade and turned it back off. After it cooled down, only one light remained when I turned it on - the orange car with an exclamation point. I drove it several blocks to an AutoZone who pulled a P0A08 code, DC/DC converter status circuit. 12v battery was over 14v. Two starts later that light went away too, and I ended up driving home uneventfully - though with clenched cheeks. I have to wait a few days for the fancy AAA membership to fully activate to bring it all the way to my hybrid guys in Tampa. I'll give them a ring tomorrow, but in the meantime I was hoping to have an idea what I could potentially be looking at. I've thumbed through some threads and am suspicious of the inverter fluid pump, but my initial search didn't uncover anything about the loud clanky noise, and it doesn't seem to make much sense that the new 12v was still happy. I'm not sure what level of repair makes sense on such a well-used vehicle - I sold my 2005 in 2016 at 220k so I've been treating every extra mile on the wagon like a gift for quite some time. I already knew I'd be getting a 2017 V when she's done for, but I'm hoping that's not what I'm looking at. Any and all advice greatly appreciated. My apologies if I end up bumping some graveyard threads if I find anything that sounds familiar.
You have quite a collection of bad warning lights but sometimes one thing inadvertently causes them all. Getting the car to the shop is the right thing to do. While not specifically inverter codes, a bad inverter is one of the few things Toyota will still cover on that car.
HV battery has a couple cells that are likely bad. Time to replace it..Tampa Hybrids should be able to help you out. Don't give up on it yet! A/C and Heater play a critical role in the death of hybrid batteries. 27mpg on the dash, 2 bars...yep. Pretty much.
Got busy today and totally spaced on giving them a call, but AAA premium tow not active until Thursday anyway. Again, there are zero lights on the dash now - the 'full constellation' of lights only showed up once, while the car was still actively overheated. After that it was 'just' the hybrid system warning light, though I don't actually recall an audible alarm. That one remaining ight went away after two more starts. I can't say I'd be overly surprised if the hybrid battery were going, 370k and twelve years a long time. Fwiw, though, the 29.2mpg on the gas is mostly a product of many hours of idling over the past few days, I was working on some stuff in an outdoor workshop and kept the car running so any of us could hop in and cool down. As recently as last week I was still getting just shy of 40mpg on a full tank on a highway day. I actually saw better than 40mpg for the first time in *years* a couple weeks ago when I had a fully in-town tank. From what I can tell, that one DC/DC code was likely the direct result of overheating. This was a long idle (park) in direct sun, I tend to keep it in the shade to idle when I can. I actually didn't realize that AC/heat was a battery killer - she's had one or the other (95% AC) on for every single one of the last 300,000mi, including 6-10hrs of idling overnight 1-2 nights a week for six years. If this is 'premature' compared to what I could have gotten out of the battery, I don't know what people expect out of them, lol.
Have you checked the coolant levels in your car's systems? For this error code, one of the reasons is indicated as inverter overheating due to poor cooling. Poor cooling may be due to insufficient coolant. Control is suspended due to overheating. (The inverter water pump with motor assembly is malfunctioning, the coolant is not sufficient, a hose is clogged, etc.) When the inverter is overheating, the DC/DC converter has self protection control that suspends the DC/DC converter control. As that time, this DTC may be stored. The suspended DC/DC converter control will return to normal by clearing the DTCs and turning the power switch off.
The fluid levels I can see all look fine, but I'm going to run down later and see if I can tell if the pink stuff appears to be circulating at all. Your post basically summarizes the most similar threads I've found, and helpfully lists a handful of the potential causes. Tampa shop opens soonish and if I can stay awake a bit longer I'll reach out and let them know a patient will be arriving in a couple of days.
Be prepared for what Todd at Tampa Hybrids finds. A clunk from the engine while sitting for an hour? or two? with the A/C on HI could be many things we can only guess about. When Todd hooks up Techstream he'll have a much clearer idea of what happened when the dash lite up like a christmas tree. So far like you we can only guess, seeing you have more than 300k hwy miles, previous head gasket replacement, and nothing mentioned in between the two, like EGR cleaning for one of the more common issue, beside the hybrid battery as mentioned above.
My apologies if I was unclear - when I said "EGR cleaning post head gasket replacement" in the first paragraph, I was trying to say that it has been performed in the time after the head gasket replacement. I'm not supposed to be 'due' to do it again for another 20-30k miles, but perhaps me doing more in-town miles instead of highway speeds up that timetable. This was certainly not how the head gasket failure presented before. I'm not sure what you mean by 'between the two' in reference to the high mileage vs the head gasket replacement. The miles were put on at a fairly steady rate of about 1000-1500mi per week (after her first several years of only 8-10k per year before my purchase) until last summer, when I switched to in town routes - I now drive fewer than 500mi most weeks. The head gasket replacement was done around 230k miles. As for the inverter fluid circulation, I can't tell for the life of me if it's circulating. If it is, it's not particularly obvious. I won't be able to get it to Tampa until next week after all, the other half insists on joining me and he can't go this week. I'm fine in a rental in the meantime, but I'll sure be happy to know if I need to find a more permanent solution.
The following key data is stored for this fault code. Related Data List DTC No. P0A08 INF Code 264 Data List Item +B Inverter Coolant Water Temperature Short Wave Highest Val A short circuit usually causes significant damage, fuses, wires or equipment blows. So, since you reported that the unit is working again, the most likely cause is overheating. Inverter Coolant Water Temperature
