1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Stuck fuel gauge

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Scott56, Jul 22, 2017.

  1. Scott56

    Scott56 Junior Member

    Joined:
    Jun 16, 2017
    40
    27
    1
    Location:
    Alabama
    Vehicle:
    2007 Prius
    Model:
    Two
    My fuel gauge has been showing full for 2 weeks straight and is just stuck there. I had disconnected the 12v battery to clean the throttle body a couple weeks ago and that is when the problem started. I don't think I was on a full tank either when that happened. Do I need to disconnect the battery after I fill up that way the electronic sensor marks that position as a full tank? This is just theory although taking all the trunk stuff and tools out at the gas station is a bit of a pain.
     
    #1 Scott56, Jul 22, 2017
  2. Kevin_Denver

    Kevin_Denver Active Member

    Joined:
    Mar 18, 2016
    581
    421
    1
    Location:
    Denver, CO
    Vehicle:
    2009 Prius
    Model:
    N/A
    The Prius' fuel gauge has very poor accuracy, and it can take as much as 250 miles in my Prius before the first bar disappears on the fuel gauge. When that happens, after that it drops much more rapidly with the miles, usually down to 2 bars with ~450-500miles. I always fill the car up at or before 2 bars, as the gauge is notoriously inaccurate due to the fuel bladder in the Prius (a couple of users have reported running out of fuel at 1 bar, before it starts to blink!). If you haven't put at least 200 miles on it since you filled it full, I wouldn't worry and just keep driving.

    If you know that you should be able to put at least 3 gallons in, you can fill up the tank to full, then just reset your odometer and mpg tracker on the screen and track how far you go before it changes. If it doesn't change by the time you should have used 7 gallons, there's a problem.

    The Prius' computer attempts to compensate for the weird readings caused by the fuel bladder sensors, so when you reset the 12V, it doesn't have a good idea how much fuel there is in there. It will recalibrate on your next tank when you fill to full, adding at least 3 gallons. No need to reset the battery each time.

    Summary: Most likely you're fine, just dealing with the Prius' "unique" (F'n weird) fuel bladder.
     
    #2 Kevin_Denver, Jul 22, 2017
    Scott56 likes this.
  3. Scott56

    Scott56 Junior Member

    Joined:
    Jun 16, 2017
    40
    27
    1
    Location:
    Alabama
    Vehicle:
    2007 Prius
    Model:
    Two
    Ok thanks Kevin I'll give it awhile then before resetting the 12v battery. There was a couple times where the fuel gauge didn't go to full after I topped it off, but that was only twice in the 10 months that I have had it. Last week I was at the pump and the fuel pump would not fill the tank except 2 seconds at a time. I was clicking the fuel pump for 4 minutes and went to a different pump at the same station and the same thing happened with that pump as well. It could have been a coincidence that they had 2 defective pumps butI go back to the station today and it is fueling like normal.

    I miss how simple cars used to be, but all cars are adopting modern design so may as well embrace the changes and headaches that go with it.
     
    #3 Scott56, Jul 22, 2017
  4. Kevin_Denver

    Kevin_Denver Active Member

    Joined:
    Mar 18, 2016
    581
    421
    1
    Location:
    Denver, CO
    Vehicle:
    2009 Prius
    Model:
    N/A
    Well this one you only have to embrace for the life of your 2nd gen Prius. The bladder is gone in the 3rd and 4th gen models. The 2nd gen Prius is the only car I know of with this "feature."
     
    #4 Kevin_Denver, Jul 22, 2017
    Scott56 likes this.
(You must log in or sign up to post here.)