power loss event

i bought a 2007 gen2 in august. drove abt 1000 miles. one day red triangle lit up. lost power abt 1 mile later. parked for an hour. drove another 40 miles home no problem. got carista obdii and dr prius. have been watching the battery. nothing obviously wrong. havent checked inverter coolant movement or battery fan. live in hot desert area.

screenshots below
show various stages of a recent drive. sat in a parking lot for a while withAC on. a mile or two later, pack voltage went into red while recharging, driving. other than that, no module has been consistely low, high, or showing odd resistence.

what might have caused the power loss event? previous owner said they never experienced such a thing. 190k miles, original traction battery.

 

overheating is reasonable theory. the drive on which power loss event occured was 140mi round trip, over 100f all day. power loss occured after sunset at 80f air temp about 5 miles after cresting a major highway incline (morongo grade, 1500' over 10 miles, two relatively steep sections).

battery code P0A0F, engine code P0121. tried dr prius "full battery test" but couldnt get "bottom voltage" reading.

 

photo of dash just before power loss:

 

Update: this problem did not recur until the end of June 2021. It has since happened twice more during the last week (mid July 2021). Four power loss events total. I'm going to start a new thread with better diagnostics soon.

 

Update: since replacing the inverter coolant pump, a related fuse, and the throttle body (with throttle position sensor) this power-loss phenomenon has not recurred. But it's only been a few weeks. There have been plenty of days over 115F here, and the battery has operated over 120F regularly. I'm trying to figure out how to keep the HV battery fan on full blast all the time, and I want to create a dedicated airconditioning duct back to the HV battery, though I'm not that skilled at these things.