Hello from Anita. I am a Newbie on this site. I have just read a discussion, comments and recommendations (THANKS!) on this site about reductions of MPG. I am at this moment sitting in the waiting room of my local Toyota dealer after being told there is nothing wrong with my my 2008 Prius; I have had a sudden reduction of my MPG from 44.5 to 33.5 after having the 12V battery jumped when I left an interior light on. (a coincidence, I don't know) I have done the suggestions here myself and the dealer also did them along with some other tests. When I pressed the "Vehicle Signal Check" while in Maintenance mode, I got a reading of 11.6 volts (the note here says it should be 12.4-12.8) The dealer said that when they did this it went up while sitting in this mode. They also did some test where there was a reading of 450 (I forgot what reading this is) and that meant that the battery was fine. They ran the car through a bunch of other tests and pronounced to me that "We cannot find anything wrong". My service rep said that he and the head tec were putting a "claim ticket" in to Toyota with the complaint so that if there enough complaints like this then maybe there will be some investigation. (my interpretation, not a quote) I am on the verge of tears. I have had my Prius for 2 1/2 years and feel very disappointed. Any more help or feedback is greatly appreciated. Anita
As I'm sure you will hear from others, the 12v battery is the most common source of otherwise unexplained low MPG. If you have followed the testing procedures and the battery failed, I would have it replaced regardless of what the dealer said. Hope you regain the faith in your Prius!
Anita, I'm afraid that the folks at your service department don't know their a$$ from a hole in the ground. These are classic symptoms of a bad 12V battery: FWIW, failling/failed 12V batteries are probably the most common problem with the Prius. The 12V batter has a service life of ~4 years... if all goes well. Fully discharging the puny 12V battery even once starts a rapid downhill slide. To compensate for the dying battery, the HSD has to divert more and more engine power to the High Voltage Battery which in turn is converted to 12 power for all the little things that are needed or used when you drive; computers and control units, lights, radio, windows, etc. I'll bet money that your 12V battery is very weak and if you don't do something quickly, it may leave you stranded soon. A new battery at the dealer should cost about $200 installed. There are other options available on the "Net, but by the symptoms you've given, you could be in a no-start situation tomorrow, vice the 4-5 days on delivery from these folks: 12 Volt (12v) Toyota Prius Auxilary Battery for Prius with installation kit Something to read: http://priuschat.com/forums/newbie-forum/73400-weird-stuff-happening-mpgs-dropping-test-battery.html Keep your chin up girl, this is most likely a very simple problem to fix. :cheer2: [ame="http://www.youtube.com/watch?v=ZBR2G-iI3-I"]YouTube- I Will Survive[/ame]
Anita, please relax & suck down some of the free tea in the waiting room. 1. Trickle charge your existing 12v battery & keep an eye on it. If it won't hold a charge then you'll have to buy a new 12v sooner rather than later. 2. If it holds a reasonable charge then you're looking at buying a 12v battery later. You can cut through some of the BS in the shop by either telling them to swap out the battery (skip the diagnosis) or buy the battery & DIY. You may find that quoting your voltages demonstrates that you have an idea of what's going on which will reduce the BS.
2 1/2 years is short. Maybe the car don't get driven often? Another thing to check is the battery connections in the trunk. Sometimes the problem is corrosion or loose connections. Good luck!
Hello all! Thank you so much for all of your responses. I am very appreciative! Getting new 12V battery today. I will report back...
Check the voltages before leaving the lot. Often enough, fully charged batteries are not installed. Your new battery will have a 1 year unlimited mileage warranty.
Yes, a lot of folks have said this. I have replaced the battery a couple of days ago and am going to report back soon! :mod:
