Gen 1 Prius temporarily loses power while driving

This just recently started happening just shy of 200k miles, 14 years.

While driving down the road, suddenly notice a power loss or no power, ie, no motor output. Sometimes the just the ICE won't accelerate, sometimes it's both ICE and Electric motive force. When this occurs, the Brake and ABS check lights turn on. After a few seconds, to 10's of seconds, then the motive power reenables and the Brake/ABS lights go out. Often the cars continues on with no repeat. Testing over a few drives, it seemed to only do it during the warmup cycle when coolant was near 160-170. However on a drive in the afternoon after it occurred in the morning; with ambient around 30 degrees, windows cracked, interior heat off, it didn't occur on the 15 minute drive, mostly freeway speed, even after about 10 minutes and cranking interior heat on. No codes are registered when this happens. I used Torque Pro and monitored things like throttle position and such, and things there seemed normal. Eng rpm dropped under 1000rpm and wasn't steady. Watching the MFG the power flows responded to the throttle (pushed/released) as if the engine was still doing what was asked (go figure, the display shows what is commanded, not what is occurring?).

A few times (2 of say 10 tests), the PS light comes on, it is more persistently 'dead', when it does 'come back', it isn't 'reliable' or faultless for the rest of the drive.

Haven't checked for rodent damage (possible). Haven't tried the blow-out-the-tin-whiskers on the throttle position pot. Neither seems likely as some trips it will run normally, with no problem occurring. Wondering if a PCB has a component failing. 12V isn't dead, the DC-DC is supplying 14V. The 12V may be dropping below 12 when starting, but it always starts and runs fine for the next say 5-10 minutes.

Has anyone seen this before? I tried searching web and forums, but there a lot out there on ABS/braking etc and didn't find my exact problem.

2002 Prius.

Bought a used Leaf, so it isn't urgent. Would like to fix it, unless the repair is too costly.

If it's an expensive repair, anyone need parts? ;-)

 

Ah thanks. I recently switched phones and hadn't remembered to transfer the Torque file. I'll try again this weekend

Do you have a reference for that?
I've used this one for a couple of years, and it was not installed during the first event. I'll check for codes, remove it, disconnect 12v, reapply, then test drive and try to reproduce. I might do that while it is still cold out.

 

We've also have a slight overfill of oil. Time to also check the throttle body, intake, etc. Glad it is warming up nicely this weekend. Good opportunity to train up the youngest son.