'09 - Won't start, with dramatic light display, 12V?
3rd Toyota and the only one that ever let me down.
A few nights ago, I drove my 2009 Prius (32k) to the grocery store, locked doors with the key fob, everything normal. Came out within 10 minutes. Pressed power and it wouldn't start. Then I noticed the odd symbol on the dashboard that looks like a random PVC joint. Checked the manual, which says something to the effect that there's something wrong with the hybrid system, and not to drive it.
I'd figured out the 'don't drive it' part, but kept mashing the power button - curiosity I suppose. I heard the sounds like the engine was running (the radio was on), and ALL the dashboard lights came on - the triangle, traction, gears, etc etc, ALL of them. New problem: I can't make it shut off. It's 11pm, phone is at home, the store came to for medicine is closing, I'm sick and want to go home, and it won't shut off. The engine is coming on and off, the interior lights work. Finally get it to turn off. Walked home, glad that I'd taken the dog to ride to the store, though the phone would have been better.
Had it towed to the Toyota dealership (free with Certified Used). Car said hybrid system was bad, plus I bought it as a former loaner car, so I have both new and certified used warranties, AND bought the 'bumper-to-bumper except what you need' additional warranty. Their diagnosis is that the 12V battery needs to be replaced. I got on this site because I thought $345 was an awful lot for a 12V battery - and it is - but thinking about it, this makes no sense. I've had dead batteries - after I didn't drive for a month, or left a radio on all night ... but not after parking for a few minutes, and definitely not with all the lights going crazy.
This probably is unrelated, but a few months ago, my MPG dropped by 20%. I drive like a little old lady and for 1.5 years have always gotten at least 45 mpg. In about August, it dropped - suddenly - to 36 tops. And it stayed bad. I checked alignment, even got new tires (after mpg dropped), tried some gas treatments. Tech at Toyota said it's because of 'winter formula" gas. In the South. Didn't happen last year - in fact, exactly never before in any car I've ever had, or in the '98 Tacoma I'm driving now. And as soon as the mileage dropped, I started buying only BP, which at least where I live has the lowest ethanol allowed. I don't think the gas engine is going off as much as it should; Tech says I'm wrong. Again, probably has nothing to do with what is rates as the big problem....
Has anyone else had something similar? I'd really appreciate any ideas.