Disable automatic fuel door closing

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.

 

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.

 

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

 

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

 

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.

 

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

 

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.

 

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.

 

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

 

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.

 

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

 

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,

 

You've always gotta 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.

 

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

 

See post #13.

 

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