Problem with gas tank/gauge

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by MennoPrius, Jul 1, 2012.

  1. MennoPrius

    MennoPrius New Member

    Jul 11, 2008
    2008 Prius
    About three months ago my GEN II 2008 Prius became cranky at the gas tank. Despite it having 1-2 bars as the balance in the tank, it would only let me add about 2.5 gallons of fuel. Used the same gas station, which had six-month-old pumps and level ground.

    Took it to shop, they kept it half a day, pronounced it taken care of, and that was that. Everything worked fine. Three days ago, just before I was to leave town on a a long-distance trip, she again would only take 2.5 gallons. Took her immediately to the shop where they worked on her and said they found nothing wrong. They were able to get her tank full.

    I drove her out of town and did fine. On the way home she showed 2 bars, so I pulled in and filled her. At 7 gallons there was no feeling like the pump thought the tank was full. I manually stopped it. Got back in the car and it showed all 10 bars. Fine, I thought. Unfortunately, even though I drove another 110 miles at 49 mpg it never budged off of 10 bars. Sitting in my garage it still shows the tank has 10 bars in it.

    Now what do I tell the garage when I take her back again besides, "Get it right this time!"?
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

    Mar 8, 2008
    Green Valley, AZ
    2015 Prius
    I think you should live with the fuel gauge as-is for a while.

    Reset the MFD trip odometer each time you buy gas. When you next stop for gas, if (for example) you have driven 400 miles since your last refueling and you get 50 mpg, then you know you must add 8 gallons before you are done. Even if the fuel pump shuts off before then, continue pumping until you've added the required quantity.

    With your most recent refueling, you may have filled the tank more than normal. You may find that the fuel gauge will start dropping down after you've driven 150 miles (or consumed 3 gallons).
  3. RobertK

    RobertK Member

    Sep 9, 2007
    Norfolk, VA
    2007 Prius
    It sounds like you need to calibrate the fuel gauge. I found the following instructions by doing a Google search for the terms fuel gauge calibration with the search limited to

    The first instructions I found were as follows:

    1. Park the vehicle so as it is level,front to back and side to side.
    2. IgOn and make sure that "Trip A " is showing on the odo ( this is where we made a mistake Embarassed ).
    3. Power down.
    4. Keep your foot off the brake.
    5. Push in and hold down the Odo/Trip button.
    6. Push the Power button twice to IgOn ( not Ready mode ).
    7. Turn the Odo/Trip off then On 3 times in 5 seconds.
    8. Continue holding the Odo/Trip button until a 6 digit code appears.
    9. Release,then push again the Odo/Trip button for another 5 seconds. The 6 digit code will change to a 5 digit code.
    10. After the middle digit,of the 5 digit code,changes to "1" release the Odo/Trip button and the odometer will return to normal reading.

    Hope this helps.

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