2006 Prius having sudden issues

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by hardtohateme, Feb 25, 2018.

  1. hardtohateme

    hardtohateme New Member

    Feb 25, 2018
    2006 Prius
    Hey guys! I’m new to Prius chat and I’ve only owned my Prius for about a year now so forgive me if what I say comes off as confusing. I bought the Prius from a seller on Craigslist. My 2006 Prius had right at 180k miles when I bought it last February and it is now at 222,687. It’s never been in a wreck and it’s had synthetic oil changes every 10k miles. The reason I got on here was because my Prius has recently in the last 2 weeks started doing some really weird things. The first thing I noticed before having any other problems was my hybrid battery draining quickly and my average MPG dropped suddenly.The morning I got up and went to work I noticed my hybrid battery wasn’t staying charged as much and my average MPG had dropped all the way to the upper 30’s. Usually I would average 46 and above and that’s with me being heavy footed. The hybrid battery would also always stay in the 3/4 range and it was wanting to stay around half and then sometimes dropping all the way down the one purple bar. I tried to ignore what I had noticed and thought maybe it had to do with the weather or something else and it would correct itself. About a week later, I had went to a friend’s house about 2 hours from where I live. When I started my Prius and had gotten not even a whole mile, the red triangle light and some other warning lights came on the dash and the hybrid battery had completely lost all of it’s charge and the ICE wouldn’t cut on. I had to pull off on the side of the road as quickly as I could and put the car in park and turn it off. My first thought was to unplug the 12v battery and see if that would reset anything and to my luck, it seemed to somewhat fix the issue. All of the warning lights were still on but the ICE kicked back in and started charging the hybrid battery so I was able to start getting down the road. I cut it off again to fill up with gas on the way home and when I turned it back on the lights were still on but everything seemed to be running fine. The next morning the red triangle appeared for just a second when I started my car and then disappeared. The check engine light was on but later in the day it eventually went off. Some other weird symptoms my Prius has had is the dashboard lights sometimes not coming on and also the A/C fan will sometimes not come on until I get going down the road a little ways. Another problem that just started today was when I would brake at a stop sign or make a sharp turn, the “red triangle of death” would come on for a split second and beep. I’m not sure if those are separate problems or if they’re somehow all related to the same issue. I’d really appreciate any advice I could get from you guys. I don’t have a ton of money to spend on trying to figure out the problem so I’d really appreciate it if someone could steer my in the right direction of where to start at.
  2. bisco

    bisco cookie crumbler

    May 11, 2005
    2012 Prius Plug-in
    Plug-in Base

    start by measuring the 12v health. but to be honest, it sounds like your hybrid battery is on the way out.

    the dash lights and fan are unrelated, and may be a bad combination display. (speedo etc.)

    best thing to do is get the trouble codes read on tech stream.
  3. exstudent

    exstudent Senior Member

    Jul 11, 2009
    Torrance, CA
    2007 Prius
    1) Get the codes read. Ideally a shop that has a Prius capable OBD2 reader.
    However, the main details you provide point to a failing HV Battery:
    • big swings in SOC (State Of Charge) of the HV Battery: green bars to purple
    • considerable drop in MPGs
    • age (2006) = 12/13 year old HV Battery, if it is still original
    Avoid module replacement from Craigslist hacks. You'll be in the same predicament: hours, days, weeks later.
    Avoid rebuilds, as these may last a little longer. But the price you pay, is only slightly less than a new OEM HV Battery.

    Internet search: oem Toyota parts [your city] [your state],
    to find Toyota dealers who sell on line at a considerable discount. Some dealers will sell an HV Battery to you, others won't. Maybe your local dealer will, and may even match or lower their asking price. The prices have come down considerably; as low as $1625. This is not a drop in replacement, as some components (various ECUs) have to be transferred from the old HV Battery case, into the new HV Battery case. Doable, but care must be taken due to high voltage.

    There is $1600 alternative, that shows promise, from member 2k1Toaster. Longevity is unknown, as it has not been around long enough.
    Prius Battery Replacement Kit (GenII/GenIII) with NEW custom cells | PriusChat
    His company's website selling his cylindicarl cells.

    2) Automotive engines can and do burn/leak oil. This means you need to check the engine oil level regularly: daily, weekly, every gas fill up, bi-weekly, etc. And top up to the top dimple of the dipstick.
    3) Dash board lights. Do you mean combo meter (speedometer, odometer) display? If yes, this is a known problem. Unfortunately, you are outside of the enhanced warranty period. You will have to repair out of pocket. Contact Matt at Texas Prius Battery Replacement Matt is a respected and knowledgeable member here. He has repaired combo meters. He also sells rebuilt and new OEM HV Batteries.
    #3 exstudent, Feb 25, 2018
    Last edited: Feb 25, 2018