Suggestions sought: cold engine stalling at 240k miles

My 2006 inexplicably lost engine power as I was leaving work last night. Brakes and power steering still worked fine. Engine was cold. Dash lights stayed lit. I couldn't shift back into drive until I turned the car off and on again. Drove home fine after that. The red triangle was on along with a red car symbol on the top left of the touch screen. No new trouble codes to explain it.

I searched the forum and saw that a failing inverter pump can cause stalling without a trouble code. Mine was replaced at 100k miles.

Not sure if it is related but the car has had codes for the catalyst system, camshaft advance and inadequate engine heat for closed loop fuel control (she is very slow to warm up). Car also burns a quart of oil every 1500 miles and the engine sometimes knocks under light throttle.

Car has high miles (245k) and I'm trying to keep her alive until I can save for a newer Prius. Thanks in advance for your suggestions about how to troubleshoot this!

 

It's still on its original high voltage battery - now I wonder how to inspect it.

The 12v battery is a few years old. Could be bad, given how it has been drained fairly quickly in the past (a jump start was required a almost a year ago after sitting briefly with accessories on and engine off).

I used a cheap bluetooth dongle and the torque android app to scan for codes. I gather that this isn't an optimal setup.

Thanks for the responses so far. Hopefully I can get this sorted out soon.

 

So the red triangle and red "!" warning light on the touchscreen both went away today mysteriously.

I wonder if it had anything to do with plugging in an elm327 obd adapter earlier that day and leaving it in when parked.