Help! Red Traingle on 2002 Prius

See 2002 Owner's Manual, p. 99: "Hybrid System Warning Light. This light comes on if there is a problem in the electric motor, inverter unit, hybrid vehicle battery, etc. If this light comes on, stop your vehicle in a safe place immediately and contact your Toyota dealer." Etc., etc. You have two options, as I see it: (1) take it to the Toyota dealer for a diagnostic check (i.e., code read-out); (2) take it to a mechanic who specializes in hybrid vehicles. As there seem to be a number of these on the west coast, you might have one in your area of Oregon. Note that most OBD diagnostic code readers cannot retrieve all of the specialized Gen. 1 codes; the Graham Mini-Scanner will, if you can find one, and of course the dealer's service dep't can, as also the independent hybrid shop. With such a low mileage car, I'd be inclined to take it to the dealer first and see what they say, then decide whether its worth fixing. Good luck, and let us know how it turns out.
Silver '02 Classic w/146K miles

 

I would to get the codes and battery checked out.

 

You can get a OBDII diagnostic code reader like CARISTA which can read codes with Dr Prius App for $30 . Your HV battery likely has a bad module or corrosion on the module contacts. Greenbean can replace the HV with a long warrantee which is ideal for a car so new-like.
Can you check the 12volt battery on the L side of the trunk with an voltmeter ? It can cause the light to go on too if it goes below 12v

 

You replaced the axle hub? On the Prius with only 32,000 miles on it? Which one? Let me guess, back right?

You could take the HV battery apart yourself and just clean the connectors. That always fixes mine. Are you mechanically inclined? If you can replace a wheel hub you should be able to do the work yourself.

 

With the hybrid battery being 18-19 years old, I would say it’s had a long good run, and I wouldn’t be surprised if it’s on its way out :/

 

Do note that in the OP's photo of the MFD screen, the icons for the power steering and the battery are both greyed out. Only the some-miscellaneous-other-problem icon on the right is red. I would take a moment to breathe, get the codes read, and find out what the miscellaneous other problem is.