Ok read a suggested thread and it says it's the 12v battery ( car has 70k miles aprox) could I get it at pepboys or Autozone? Still the symptoms are: HV Battery loses almost all charge over night. Sometimes it won't start HV battery loses charge fast while cruising in the city (I used to see it getting green at the highways with cruise control and now it doesn't happen) Red warning light goes on randomly. _________________ Don't have time to take it to the dealership for now. Will do though. Still everytime I go I have to discuss with the guy because they think Im stupid... (once they wanted to charge me $100 for gas cap "adjustment". Other was "bitten cables"... $500 and got it fixed at other dealer for $200)
Which warning light goes on? The 12V battery is a special size and you won't be able to buy the correct replacement at a discount auto parts store. The easiest solution would be to buy the correct battery at your local Toyota dealer. Alternatively, if you can replace the battery terminal connectors, then you could install an Optima yellow-top battery (search for that if you are interested.)
If you're still on the original 12 volt, you should replace it now. It's likely bad already or about to be. One way of finding out the condition of the 12 volt is via http://priuschat.com/forums/newbie-...g-mpgs-dropping-test-battery.html#post1020264. The Optima battery Patrick mentions w/new terminals of the proper size is at Toyota Prius 12 Volt Auxiliary Battery with install kit for 2004 - 10. I just changed mine to this myself yesterday.
i gues because your 12volt is failing the SOC on your MFD is dropping well its just visual not for real. because a low voltage maybe the cause of the HV battery ECU to reset and report a standard 60% soc even if you drove your car in last night with al green bars.
I'd recommend the elearnaid.com Optima battery as well, given your location and apparent dislike for your dealer. They ship Priority Mail. If you have a 12V battery charger, try putting that on overnight in the meantime at a 4 amp or less setting.
The 12V battery lists as $140 in the US and should cost about $200 installed at a dealer. The eLearnaid Optima kit is comparable but requires tools and hand strength to install.
Checked the mfd today... Yeap Its the battery. Ran the car through town came back turned it off checked the readings and it went down from 14 to 9.0 volts playing peek-a-boo (# went up and down not consistent) I then turned all the lights and pressed the brake pedal and the car went off. The car is not mine is my parents I own a 1992 240sx but the radiator fan went out and haven't taken time to fix it.
