I have a 2005 Camry XLE 4 cyl. and I'd like to put in a new battery. I read somewhere that it's possible maintain the radio/garage door opener settings by connecting a small 9V battery to the PCM while the main battery is being switched out.
My question is, if this is so, how is it done and where is the Powertrain Control Module? Or is it just not worth the bother/risk?
Thanks, Rob