Sudden loss of hybrid system while driving

2015 Prius 4 with ~ 46k miles. No previous problems.
Driving home from a hike. Car abruptly does a small shake, dash lights up with:

Check engine light
Master Warning light
Slip indicator light
Brake system warning light
and of course: [Check Hybrid System......] warning in huge letters.

Car did continue to run. Pulled over ASAP off the freeway in about 1 mile. Shut off engine. Died with a stutter and some extended 'clanking'. Not normal.
Oil was OK, fresh change less than a 1000 miles ago.

Tried to start > it did, ICE only with same warning lights. Drove home cautiously. Shuddered a tad on initial acceleration, had.....lousy....power, but when going along at residential speeds seemed almost normal except for the warnings and lack of power.

Have a Techstream program. Had not used it. Could not get it to connect. Sigh.
Tried an OBDII and an Android app called [Car Scanner]
Got a [UO29A] code. That's the only code, at least with this app.

Googling that gets me some further confusing results.
-bad connection with the skid control unit
-lost communication with the hybrid battery pack
-lost communication with the hybrid battery pack sensor

Brand new to Prius and vehicles like this. Seems like there is some issue with a poor connection...maybe?
Any clues on what to check?

 

Thanks for the above replies. I have a bit more info.
12v battery seemed fine > 12.26v, and that's after screwing around for awhile with the system on trying to get DTC codes.

Pulled what I think is the HV 'fuse' (not really a fuse, more of a connector). It's a large orange plug thing in the back that looks to connect the HV battery. After I did that, when I fired the car up all the dash alerts were gone. Drove it around the block, maybe half mile. Completely normal behavior.
Puzzle, eh?

Car is 2nd hand. Previous owner seemed to be OCD about taking care of it. It is in impressively good shape with all previous work, both dealer and personal noted. This is a big part of the reason I bought the car. It's been functioning flawlessly for about a month+ and maybe 800 miles.
So....is a 2015 with those kind of miles, second owner, still under warranty....should this problem show it's ugly self again?

No evidence of vermin chewing and it's been garaged most of it's life. I think that is unlikely.

 

Help! Murphy has it in for me!
Drove Prius the next day. No dash lights, ran absolutely normal for ~ 5 miles. On parking the dash lit up with the [Master Warning] and [Check Engine] lights. It shut down with that weird extended shaking and clanking like the first time.


Went shopping, less than an hour. Tried starting > same dash warning + [Check Hybrid System......] added in.
Pulled the orange 'breaker' (cross fingers...) Tried again > Same behavior. Argh!

Drove it home. Hybrid system working this time. Except for the dash warning lights it seemed normal. Shut down normally, no weirdness.
Checked for DTC codes > same [UO29A].

Next day, fired it up. No dash lights at all, seems normal. Did not drive it.
Checked for DTC codes > residual? [UO29A] still there. Tried removing code with [Car Scanner] app > erased, no problem.

The scanner app will do a 'deep scan'. Ran it, took almost 20" > no codes at all.

I am baffled. I figure if I take it in, they'll find nothing. Then it'll light up like a Christmas tree on the drive home.

 

Check connections where?

I'm struggling with Techstream. I got a download that was 'supposed' to work on Win10x64. Directions were gawd awful. There are SO many different approaches, program versions, windows versions. etc., to getting the program to work it is frustrating.
Works on the laptop. USB connector is recognized (the XHorse test). Will not connect to car.

I have a BAFX OBD2. Works with The [Car Scanner]. Won't work with [Torque] or [Carista]. What's with that? I can understand an OBD2 not working at all, but if it's sending, why can't another app pick it up?

 

This is the definition of conflicted.

Took the Prius to the former owner that has a working copy of Techstream. About 15 miles one way, worked perfectly. Techstream shows nothing, no errors.
Note-I did erase the DTC codes with a phone app. That worked, apparently quite well......
Techstream found no history.

Drove back home, no problems. Uh, that's good?
Sure don't feel secure about this.

 

2 more days of driving around town. Works perfectly.
Unwilling to go for drives far from home + freeway right now.

 

I....don't.....think....so. OTOH, this whole hybrid thing is new to me. It doesn't sound particularly weird. The "hybrid system going off line" had nothing to do with braking, so I don't think that's the issue.

No, I have not gone the dealer yet. At this point I have a car that runs absolutely normally, with no dash alerts, and no DTC codes, according to the previous owner's Techstream.
What do I tell the dealer? I have 'my story', but at this point I have no PROOF, no problems, no DTC codes.

Murphy is looking after me....for sure.

 

3 short trips with the Prius > no problems, normal operation.
Decided to risk a longer trip with freeway; 45 miles, no issues.

Don't know what to think about that. One thing if it was a nuisance problem that went away, but the entire hybrid system simply quit working. Now it seems fine. Weird.