Multiple Warning Lights - Pictures Attached

My wife has a 2007 Prius with approx. 110k miles. We installed a new 12V battery approx. 1 1/2 year ago at 81k miles. A few months ago (Mar/Apr), her dash would randomly display the warning lights shown in the 1st image: Brake System, ABS, and VSC (the TPMS light is always on due to faulty tire pressure sensors and appears unrelated).

The car seemed to be driving normally with no abnormal behavior. Whenever this happened, my wife would pull over, turn off the car, and restart - at which points all the warning lights would disappear.

Even though our 12V battery is relatively new, I did check the voltage of that battery using the MFD's on-board diagnostic screens as explained by other posts on this board. Voltage was within the normal range with the HID lights both on and off.

The lights hadn't come back on for a while, but today we now have different warning lights as shown in the 2nd and 3rd images: Master Warning Light, Check Engine, and Hybrid System (red exclamation point set inside a car symbol). My wife says the engine seems to be working harder than normal when taking off from a stop, which I believed to mean that the hybrid system may not be engaging as normal. However, the hybrid battery seems to be going through normal cycles of charge/discharge as indicated by the multi-function display.

We are going to take the car into a dealership tomorrow but wanted to ask in advance of that if anyone on the board has ideas on what may be causing this - and whether the two sets of warning lights are connected? I tried searching other posts on various combinations of warning lights, but couldn't come up with anything conclusive.

Thanks in advance

 

Thanks to everyone for the help. The car unfortunately died at a stoplight on the way home before we could take it into the dealership. My wife confirmed that the hybrid battery charge level on the MFD was at zero, but was able to get the car to a nearby gas station under minimal battery power and then have it towed to a nearby repair shop. The car has the following codes:

P3000 - Hybrid battery malfunction
P3016 - Cell #6 voltage issue

After reading through some of the numerous threads on rebuilds vs. replacement, I wanted to get your input on the following:

1) If we rebuild and rebalance the battery with a replacement cell, how likely is it that we will run into a similar issue with another cell a few months from now?

2) How do I determine when the hybrid battery's cooling fan is operating? I know that it draws in air from the cabin, but have not been able to distinguish its noise from the cabin air fans.

3) Previous threads and blog posts by Luscious Garage suggest that this fan needs to be cleaned regularly. Is this easy enough to do when we have the battery rebuilt or replaced?

4) Is there anything else we can do to prevent heat stress? We live in Raleigh, NC where the temperatures have been 90 F+ for the past few weeks, and the car does sit in full sun for most of the time after being parked. Will leaving the windows down slightly help at all, or is this too minimal to make much difference?

Also; In terms of the inverter water pump, that was replaced under warranty / recall by the previous owner at approx. 60k miles - so I think that one is ruled out (I would normally check this in the way usnavystgc suggests, but but the car is currently out of commission)

 

Update on the repair work we did in 2014 at 111k miles: replacing the problem cell (#6) and rebalancing the battery pack cost us $500 and got us another 31k miles / 20 months of life before ending up with the P0A80 error code. The technician that did our work obviously didn't make any promises on how long this fix might last, but did indicate that our battery was at 23 milliohms when he repaired it - which is in between the typical 19 milliohm rating when new and the 30+ he typically sees when batteries fail for good.

If those resistance ratings are wrong or not in line with others' experience, I'd be glad to hear your thoughts...