Hope I'm in the correct forum. Apologies if not. My 2018 Prius Prime gas gauge showed one dot remaining. After filling two gallons, the gas began spilling on my foot. Put in one more gallon before I could see it was going to overflow again. So stopped and went home to query this Forum. This is the second time I've tried to fill the tank since I received it in April, first fill-up was no problem. Am I doing something wrong? Any suggestions welcomed!
WAG:The anti-siphoning valve is malfunctioning. Get the dealer involved as this could be a safety issue on top of the inconvenience.
There have been several threads on PRIME or Gen4 Prius having problem accepting gas. It could be defective valve as schja01 suggested, but it may also be simple mechanical malfunction. In most case, if you close the gas cap and lid and go back to the car and push the gas lid open button under the dash again, it will reset the valve and should take full capacity of the gas. Read this thread describing this phenomenon. Fuel Filling Problem | PriusChat
The OP says several gallons was/were accepted before the overflow so whatever happened took a while so I'm withdrawing my antisiphon valve malfunction and am now going with the filler handle was up against the door switch and didn't initially trip the switch until after a few gallons flowed. (all one sentence my 5th grade English teacher would chastise me for that) Waiting for the OP to report back.
FWIW, 2020 model has modification on the fuel lid switch which prevent the accidental push to signal the lid being closed while fueling. I couldn't find the thread showing picture of the new switch with guard on it. OP's car is 2018 PRIME so it has no guard around the switch as shown in the pic on here: Fuel Filling Problem | PriusChat
I'll chime in too. It was almost certainly the door switch. The nozzle handle shield bumped the switch partway into the fill-up and closed the valve in the tank. Only way to finish filling is to hit the fuel door opening button on the dash again. I've read enough stories about it here that, so far, I haven't done that but I can see how easy it would be. Especially when I only get gas every 2-3 months.
I will be refueling soon for the first time in 3 months. Hope I can avoid bumping the switch. What does it look like?
Successfully filled my 2018 Prime this morning! Yay! Thank-you all for your comments. I panicked when the gas overflowed onto my feet. Got home and remembered PriusChat probably has the answer. And special thanks to Salamander_King's picture. My first reaction to someone mentioning a "switch" was, "What switch?"! Picture was worth a thousand words! Phew, I can relax today. Thanks again!
FYI, I found the thread showing new and improved fuel door switch with a guard. For the 2020 model, accidentally hitting the fuel door latch to activate door closed signal before fueling is less of problem. See the pic here: Problems refueling | PriusChat The 2019 and earlier model pic is on my comment before the linked one for comparison.
Would this be a "design fail" by Toyota, something so finicky and easy to mess up? Particularly being a serious safety and environmental concern.
Yes, it is. That's why Toyota fixed it for 2020 models. They should recall earlier models to install the "guard" as shown in the pic the pic here: Problems refueling | PriusChat The 2019 and earlier model pic is on my comment before the linked one for comparison.
This problem must not affect the vapor recovery nozzles used in CA, as I've not had the problem on my 2017.
