Disable automatic fuel door closing

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by onlynark, Jul 17, 2017 at 12:11 AM.

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  1. onlynark

    onlynark Member

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    my friend has a 2016 Prius IV and she says that she cannot keep the fuel door open for more than 10 minutes at a time. If it stays open for a longer period of time, she says it automatically closes. She uses a special refueling service that requires access to the fuel tank. Is there a way to disable this feature? She'd like to keep it open for more than 10 minutes.

    Thanks
     
  2. Elektroingenieur

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    The fuel lid and fuel tank cap do not close automatically, but as the Owner’s Manual (20.7 MB PDF) mentions on page 264, a fuel vapor-containment valve closes after 30 minutes:

    Finish refueling within 30 minutes. If more than 30 minutes passes, the internal valve closes. In this condition, fuel may overflow during the refueling process. Press the fuel filler door opener switch again.​

    This is a required part of the evaporative emissions control system (CARB technical information; simplified explanation). It cannot be disabled or modified without invalidating the vehicle’s emissions certification, and as a practical matter, I don’t know of any way to do so without cooperation from Toyota or the ability to reverse-engineer and modify the object code in the relevant electronic control module.

    If the car must be kept locked and the “special refueling service” can’t be trusted with keys, I imagine the connections for the opener switch could be extended outside the car or connected to a wireless remote control of some kind. The existing switch wiring is shown in the Fuel Lid Opener section of the Electrical Wiring Diagram, available by subscription to techinfo.toyota.com.
     
  3. Prodigyplace

    Prodigyplace Senior Member

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    If your friend is in the US, it should be 30 minutes by design to meet EPA regulations. Disabling it and driving it in the US would be illegal.
     
  4. onlynark

    onlynark Member

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    Thanks guys, that is exactly what it is! So there is no way to just leave the fuel door open? Bummer :(.
     
  5. Sam Spade

    Sam Spade Active Member

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    So, what exactly is this "special refueling service " ?
    And why would the fuel door need to be open for so long ??
     
  6. Prodigyplace

    Prodigyplace Senior Member

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    If you leave it open, you get a warning on the center dash screen to close the door.
     
  7. onlynark

    onlynark Member

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    At her place of work, there is this company that comes around between 10 AM and noon to refill cars with gas (it's essential a small mobile gas tanker). So she would need to leave the fuel door open for up to a couple hours until the car gets refilled. She is then gets billed automatically by the company. Many tech companies have this refueling service. My gf hasn't gone to a gas station in over a year.
     
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  8. Prodigyplace

    Prodigyplace Senior Member

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    If you leave it open there is still the 30 minute timer before the tank valve closes off the filler neck. Thank he EPA for that! The Prius in Europe do not have this feature/bug.
     
    #8 Prodigyplace, Jul 17, 2017 at 8:05 PM
    Last edited: Jul 18, 2017 at 5:40 AM
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  9. Mendel Leisk

    Mendel Leisk Lapsed Cargo Cultist

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    Is that true? Is it mandatory? All new US cars are thus? I wouldn't doubt it, just wondering.
     
  10. Prodigyplace

    Prodigyplace Senior Member

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    There is a mandate to control escaping fuel vapors Toyota's system appears to seal off the fuel neck controlled by the fuel door switch and a timer.
     
  11. FuelMiser

    FuelMiser Active Member

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    I'll bet this "feature" of the refueling system was discovered when this refueling service tried to fill her car, and since the internal valve had shut, the fuel spilled out the filler neck! So much for containing fuel vapors.
     
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  12. Sam Spade

    Sam Spade Active Member

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    Apparently you have never lived in an area where the air is BROWN.
    Maybe you should thank the EPA for that. :p
     
  13. Sam Spade

    Sam Spade Active Member

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    Don't see how that is any better than the little spring operated flap that is present in the filler neck of most cars these days.
     
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  14. onlynark

    onlynark Member

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    Not sure, how they found out. Just annoying as this refueling service seems to be gaining in popularity.
     
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  15. bisco

    bisco cookie crumbler

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    i wonder why other cars don't have this problem if it's an epa regulation.
     
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  16. Prodigyplace

    Prodigyplace Senior Member

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    The vapors must be controlled. I think Toyota's solution is a little unusual, but it apparently got approval. I know European Prius do not have this issue,
     
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  17. Mendel Leisk

    Mendel Leisk Lapsed Cargo Cultist

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    You've always got to love a solution, that compounds the problem. Aren't modern gas cans the same: lots of YouTube videos on how make them functional, defeat the child-proof caps and so on.
     
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  18. bisco

    bisco cookie crumbler

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    hard to believe toy is the only one, but not being able to fill up in 30 minutes is a new one on me.
     
  19. Sam Spade

    Sam Spade Active Member

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    See post #13.
     
  20. bisco

    bisco cookie crumbler

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    isn't that what all prius have had up to gen 4?
     
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