2017 V Trip MGP Error

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by Kenny94945, Nov 10, 2025 at 1:04 PM.

  1. Kenny94945

    Kenny94945 Active Member

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    2016 Prius v wagon
    Model:
    Four
    My per trip dash readout of mpg is not accurate.
    Before this issue it always read around 45 mpg.
    Now it is reading between 60-80 mpg.
    Driving style/ travel locations have not changed.
    Drivability and fuel level gauge are not affected.

    Searching indicates this is a sensor - in the gas tank?
    Might be covered under the emissions warranty, which, if 8 years, has expired.

    Anyone else experienced this issue?
    Is it a sensor?
    Any tricks, like 12 volt battery disconnect or a strong dose of Techron a cure?
    Accessing the tank can be a burdon, so.......

    All comments appreciated.
     
    #1 Kenny94945, Nov 10, 2025 at 1:04 PM
  2. rjparker

    rjparker Tu Humilde Sirviente

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    First I would make sure the dash was reporting avg mpg, not instantaneous.

    Hardware involved includes the wheel speed sensors which generate speed via the skid ecu inside the brake booster. Generally those inputs would generate codes if bad but anything is possible.

    I would certainly reset things with a 12v power cycle.
     
    #2 rjparker, Nov 10, 2025 at 1:37 PM
  3. fuzzy1

    fuzzy1 Senior Member

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    I'd need to know more detail before declaring it 'not accurate'. For certain trips under favorable conditions, it is real. Though these conditions generally don't repeat for multiple trips.
     
    #3 fuzzy1, Nov 10, 2025 at 2:42 PM
  4. Kenny94945

    Kenny94945 Active Member

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    1) Reporting the average per trip.
    Did not think necessary, yet I could take a photo of the screen I am refering to.
    2) More info?
    Trips remain the same.
    The screen used to report about 45 mpg at the end of my journey,
    now it is reporting 80 mpg.
    The issue has been occurring for a few months, so I decided to ask our forum.

    Seems 12V battery disconnect is called for as a first gamble.
    Will plug in my generic code reader.
    There are no warning lights lit.
    Will update with findings.
     
    #4 Kenny94945, Nov 10, 2025 at 3:48 PM
  5. Kenny94945

    Kenny94945 Active Member

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    Four
    Here's the screen photo... lower right corner : Ave MPG
     

    Attached Files:

    #5 Kenny94945, Nov 10, 2025 at 4:30 PM
  6. fuzzy1

    fuzzy1 Senior Member

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    I'm seeing 0.0, not 80?

    80 mpg is not unreasonable under some special conditions over short to moderate distances, such as warm starts, elevation loss, tailwinds, and low speeds. But they should be fully offset by below-normal mpg in unfavorable conditions, so that full tank refills should show mpgs much closer to normal.
     
    #6 fuzzy1, Nov 10, 2025 at 9:06 PM
  7. Kenny94945

    Kenny94945 Active Member

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    Okay, the 0.0 was with the car off after being parked...I started it, while remaining in park, to obtain the dash screen photo.

    If I was to start the car and travel, the 0.0 would change and report the average MPG experienced during the trip, reporting MPG at the end of the trip when I engage park.
    Then the engine would be turned off.
    Upon restart the dash would again read 0.0 which is normal.
    This is how the dash system has always worked :)

    But now, my question remains...

    At the end of a trip, my dash readout has become inaccurate, reading 80 mpg, instead of the 45 it has always read out.

    I have researched and the internet indicates this read out error is due to a sensor in the gas tank.

    My Questions...

    Have any co-members experienced this issue/ complaint?
    Is it a sensor and/ or what other co-members have found?

    Thanks again for reading and any replies :)

    PS I have yet to disconnect the 12v battery or plug in my OBD reader.
     
    #7 Kenny94945, Nov 11, 2025 at 5:23 AM
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