All dash lights come on in 2006 Prius

I have a 2006 Prius and was just on vacation for two weeks and my Prius was stored in my garage. My wife just drove the Prius about 6 miles and all the dash lights came on. The car still drives, but the cruise control won't engage. A few months back I replaced the aux 12 V battery as it somehow died, so I don't think that is the problem. When the car is off, the aux battery voltage is 12.5 volts. When it is running the voltage is 13.9 volts. I disconnected the aux battery and then reconnected it and all the problems went away for a while. Cruise control worked again, too. I just drove it a few more miles and it happened again and just as I got home to go up my steep driveway it would only go about 3 mph. Is that the "limp mode" I have heard about? Anybody know what this might be? All the dash light are lit - red triangle, check engine, VSC, Brake System, etc. I am a newbie to this site, but I did a search and didn't find much that sounded like this problem. All the lights came on previously when my aux battery died, but the car wouldn't start, so this is somewhat different.