Master Warning, VSC, Check Engine, and Brake Warning Lights

I bought a 2006 Prius last October and it's been a great car so far. On Monday while I was driving home from work a bunch of warning lights came on. The car drove okay for the next couple miles and then the recharging system seemed to go a little haywire. The battery meter went down to one purple bar and then charged up to full green very quickly (within 1/2 mile or so). Once it hit full green it didn't want to use the battery power so the engine kept trying to charge the system. I tried putting the transmission in "B" while I was going downhill to avoid using regenerative braking but the car kept shuddering and charging the battery.

Got it home. Let it sit for a couple hours and jumped into Maintenance mode. The 12V battery was hovering between 11.8V and 11.9V with the car off. Turning the headlights on dropped it down to 11.2-11.3V. The battery level jumped to 14.0V with the car running. Not completely trusting the computer, I also used a multimeter and it read 12.4V with the car off.

After pulling the negative cable for 15 minutes the warning lights disappeared and I was able to drive to work this morning without issue. This afternoon however when I went to turn the car on after work, the same lights popped up and and the same odd behavior with the battery meter going to one bar, jumping up to full green, and then not charging/discharging correctly (shuddering when battery was fully charged and charging system was still trying to feed it power).

After searching around a little it sounds like the problem could be a bad 12V battery (although the multimeter indicated 12.4V with the engine off), a bad cell in the main battery pack, or possibly a bad inverter pump. Any thoughts?

 

I checked the inverter pump reservoir like you guys suggested and I can't see any fluid movement with the car in Ready mode (engine is running). I let it run for awhile and even took the cap off to look inside but the fluid never moved.

I also checked the 12V battery and it still showed 11.9V with all accessories off and 11.4V with the headlights on according to the computer. The multimeter showed 12.16V with no accessories and 11.5V with the headlights on. The voltage remained fairly steady at 11.5V while I checked it for 20 seconds.

Looks like I need to get the car towed to the nearest dealership and hopefully Toyota will replace the pump under the recall notice.

 

I got it towed to the dealership and they said the main battery pack needs to be replaced. They quoted me ~$3000 to replace the pack but I'm thinking there are better options out there. They also didn't think the inverter pump was bad but I didn't see any fluid flow when I looked in the reservoir. *shrugs*

Any opinions on getting a replacement battery pack through someone like PriusRebuilders.com? They have a replacement pack using Gen II cells for $1200 shipped or with Gen III cells for $1700 shipped.

 

I'm located just outside of Kansas City.

Seems funny to me too. The only problem is I'll have to figure out a way to get it to another dealership (~10-15 miles away) and pay another diagnostic fee. But in the face of paying $3000+ it's probably a good idea to get a second opinion.

 

Thanks for the help gents. The dealership gave me a good deal on a newer Prius and enough in trade-in to make it worth my while. With how hectic life is right now I decided I'd rather not try to fix the thing myself. Normally I enjoy doing my own wrenching but trying to get time off work and plus the $1200-1400 to replace both batteries made me rethink that route.

Hopefully the newer Prius will work well for many long years.