Got in the car two days ago and pushed the Power button... The alarm activated... at least that's what I think it was. The emergency lights blinked and the horn honked until I clicked the smart key unlock button. Thing is, I didn't opt in on the alarm. I've seen some other mystery alarm sounds in threads, but no real answers.
Is your 12v battery the original? If so, it probably needs to be replaced. A low 12v battery will present strange alarms shortly before it dies.
You can check it yourself without tools using the built-in test described here: http://priuschat.com/forums/newbie-forum/73400-weird-stuff-happening-mpgs-dropping-test-battery.html
In the event that I need to replace my 12v battery... how much and where? I called AutoZone and they didn't seem to have anything. Seems like there are some othe rbatteries out there, though.
I agree that it is likely your battery needs to be replaced if it is original equipment. I bought a battery last fall for my 2004 from Precision Toyota, Tucson, for $139 plus tax. Suggest you call the various Toyota dealer parts depts near you to determine their pricing.
You could buy an Optima battery, considered by many to be superior to the OEM. They're available from: 12 Volt (12v) Toyota Prius Auxilary Battery for 2004, 2005, 2006, 2007, 2008, 2009 and 2010 with installation kit I put one in my 05 last year, and it has been doing very well, just be sure to buy the installation kit as the terminals are different diameter than the OEM battery. Arnie
There is no after-market drop-in direct replacement. A new Toyota battery and the eLearnaid kit are the only easy options; everything else requires some adaptation.
