Lojack will drain the Prius 12V auxillary battery and is a bad idea. When I bought my 2006 Prius from the dealer, they would only sell the car with lojack installed (which of course they charged me an extra $750). It turns out lojack drains the battery and if the lojack internal battery is not replaced, the drain on the Prius 12V aux battery is higher. Since 2006 I have experienced several dozen times the dashboard warning lights come on with the right triangle and I would lose power braking and power steering. Stopping the car and starting the car fixed the problem. The dealer maintenance department could not diagnosis this problem to a root cause since so many error messages were generated. So I took off the lojack a year ago and have not experienced this problem since. I now believe root cause is the 12V aux battery voltage would drop below a critical voltage where the on board computer would malfunction and get wedged and report lots of error messages. Turning the car off and on again resets the computer. I hope this helps someone who might be experiencing the same problem and who has Lojack installed. Dave
Apparently the toyota DENSO battery is not resistant to a deep discharge, do it just once and the battery becomes toast. check out my thread on how to get the custom Johnston controls Optima battery for under $125 with an advance auto coupon, ebates 12% cash back and $25 optima mail in rebate. You're going to need one sooner or later and with this deal it becomes much cheaper than a toyota DENSO battery. I have recommended an optima for anyone using a subwoofer or auxillary amp, but it looks like it would be good for anyone using Lojack as well.
I'm not so sure about all that. I have a 2010 Prius w/LoJack for around 8 months and havent had any issues.
well OP claims to have a problem, perhaps people with gen II Prius complained about the Lojack battery being insufficient so they beefed it up for the gen III model, explaining why you don't have a problem. I think an Optima is a wise choice for any Prius owner, but if you are running extra non-Toyota accessories using an Optima goes from a wise decision to a necessary one.
