09 Prius - Red triangle issue

I'm new here and hope this is an okay place to post this. My wife has an '09 Prius. The other day when she got in to drive the car, it would not start up. She called me and I came to check on it, there were a few lights on the dash including the red triangle. I noticed quickly that the lights were all very dim (it was dark outside so it was easily noticeable) my first thought was the 12v battery. A little more investigation confirmed this and we went the next day and bought a new battery and installed it. We then got in to drive it again for a test drive to make sure everything was running smoothly. For a few miles everything seemed good but when we stopped at a red light and turned on the AC the triangle came back up. We pulled off the road and checked it out again but I couldn't find any apparent issues. We also turned the car off but when we turned it back on the dash lit up again with several lights and the car wouldn't go into any gear except neutral. I called her dad who is much more knowledgeable about cars than I am and he came to check it out too. He opened the trunk and messed with the battery cords a bit and that got rid of the light and allowed the car to start. However, as soon as we pulled out of the parking lot the light came back on. It was a short distance to our house so we just kept going with the red light on until we got home. When we got there we checked it out again and tried what he did with the battery but this time to no avail. Now, the red light is on constantly if the car is on as well as several other dash lights. The shifter will not go anywhere except neutral and the "B" engine braking option is not even presented as an option on the screen to shift to. Any ideas on what this issue could be? Thanks!

 

Thanks for the replies! I checked the battery voltage via the settings menu on the radio - accessing it by holding options and turning the headlights on and off 3 times - sorry, not sure exactly what that menu is called. And it seemed to be good. I think it was reading at 11.7V. I ordered a code scanner from Amazon which should be here in a couple on Saturday. I'll update you all when I get the scanner in and check the codes.

 

about 170,000. Car has always ran pretty well. It's got some body damage from a couple accidents but the internals have always been pretty sound up till now.

 

Okay - sorry for the long wait, had a very busy week and didn't have much time to check on the car. First off - retested the battery tonight and it tested at a little over 14 volts which I understand is about standard. Red light was still on but no check engine. It let me put it in gear, I drove it about a mile or so and everything was well. Turned on A/C, radio, windshield wipers and headlights and still seemed good. Got back to the house and plugged in the code scanner, it brought up 2 codes but they were N/A 01 and N/A 02 which I understand to mean that it can't read the codes so not sure what that means. Anyway, I cleared the codes and the red light went away. Let it set for a few minutes and turned it off. Tried turning it back on, got red light and a slew of dash lights and it wouldn't allow me to pull it into any gear aside from neutral. Checked battery voltage and it was sitting at 10.8 that time. Turned it off again and let it set for several minutes, turned on again and everything came on fine, not even a red light and battery was back to reading at 14+. I have no earthly idea what it's problem is. Any ideas? I'm calling my mechanic tomorrow to see if I can bring it to him and let him see what he can find out.

 

Will check on that as well, thank you.

 

Started car up today and it came on but with red triangle and several dash lights. Took it on a drive and noticed the hybrid battery is not charging at all. Does this always entail an issue with the hybrid batteries or can it be something else causing that?

 

That's what I was afraid of. It's not worth investing in. It's got some extensive body damage on the front after a couple accidents. They never damaged the internal parts but the body on the front is held together essentially with zip ties and prayers. I'm gonna take it to my mechanic this week to give me a final verdict but I'm afraid we'll be in the market for a new car soon.