Red triangle of Doom

Typically, a dying 12v battery will give similar indications. A loss of 12v power will cause the fuel to show one blinking dot until the level sensor recalibrates itself. I would start by verifying the 12v battery and it's connections at the battery terminals and at the (-) connection on the car body. It would be prudent to read any codes that are present (should have something from the RTOD or CEL.)

 

check the neg to ground connection as well, if you haven't already.

a load test at the front jump point is a good indicator

 

The car does, have you asked it yet?

The master warning light (sometimes called the RTOD) comes on for any of around two hundred reasons. Those reasons are identified by trouble codes that can be read from the car. The light means to read the codes.

Some of the reasons are quite minor and easy/cheap to fix, some are bigger deals. There's a whole range. Trying to guess before having the codes might make sense if the possible reasons numbered two or three or five or six, but not so much when they're a couple hundred.

 

Your car has a "battery ECU" inside the battery, with detailed information about it, and an "HV ECU" under the dash, whose job is to be the orchestra conductor for the other ECUs in the car.

The P3000 code comes from the HV ECU, and essentially means "the battery ECU told me something is up back there".

The next level of detail you can get (which may require a better scan tool) would be the three-digit subcode for the P3000, which will be the HV ECU saying whether the battery ECU seemed to be talking about the battery itself, the fuse, the battery cooling system, battery being too far discharged, or overall voltage too low.

The best level of detail (which also may require a better scan tool) would be to get the codes and readings from the battery ECU itself, and not just the HV ECU's summary of what the battery ECU told it.

 

Look around for a mech with tech stream diagnostic software. If you can’t find one, you’ll have to drive the 50 miles

 

Maybe these guys?
https://www.aaaokeechobee.com/Okeechobee-electric-hybrid.html
Or
Hybrid Vehicle Service & Repairs by Experienced Technicians - Hi-Tek Auto | Okeechobee, FL

 

Also another quick check is with your car off for the night so it is cool. remove the cap of the hybrid coolant resivouir. the small one slightly right of center by the inverter. Turn the car on to the "READY" light is on. make sure the coolant in the resivour is circulating. the coolant level should be moving to where you can see it in the tank. If not your Hybrid Coolant pump is out and needs to be replaced. The error code for this is P0A93. but you will need to read the code withthe Dr Prius App or Techstream.

 

when my 12volt battery went bad the car went silly. Errors, lights, bells....bought a new one for $200. problems all solved. If you live where it is hot.....and you do. If the battery is more than 3 years old..........might be worth it. Most Auto parts stores will take it back if you don't need it. And make sure all connections are tight. Especially the negative from the battery to the chassis. That bolt sometimes can be loose.

 

My experience doesn't support the idea of cars often going "silly" because of a bad 12 volt battery. But there are lots of posts on that theme, and a big part of the reason is that people who gravitate to that picture of what's happening usually do so instead of finding out what trouble codes they have or what those codes mean, because it's an "easy" explanation.

In many cases, if you could have talked the same people into finding out what trouble codes were actually behind the errors, lights, and bells they had, they would have turned out to be either:

• codes explicitly reporting low supply voltages. Several of the car's ECUs can report those, and when you get those codes because of a low battery, of course nothing "went silly" at all, the ECUs did their jobs and reported what really happened. Or,
• codes all unrelated to the battery or supply voltage, and probably accurately reporting other issues in the car. But they didn't come back right away after battery replacement cleared them (and different codes have detection conditions that can take very different amounts of time to redetect), so the owner chalked it all up to "car went silly" and declared case closed.

Again, because people with this prior belief usually won't even have found out what trouble codes are being reported ("why bother to read those if the car's just going silly?"), there's generally no finding out what really did or didn't happen in those cases.