0 miles to empty, but only 7.4gal fill up?

it sounds like the carbon canister in the fuel system might be saturated from overfilling. anyway, it should take 9 or 10 gallons when the last pip flashes. i think theres 2+ gallons reserve after that.

 

i'm not sure. maybe something else is wrong. either way, you should be covered.

 

How many gas gauge bars were showing just before and just after your fillups?

It should have shown a single blinking bar when DTE showed 0 miles remaining (and it should have been blinking roughly 20-25 miles before that). If more, something may be scrambling the DTE display. Normally I'd suspect a 1-2 gallon addition not long before the full refill, but that doesn't fit your description.

It should have shown 10 bars after fillup, and continued to show that for 50+ miles afterwards. If less, the pump may be shutting off prematurely, before the normal 'fill' point.

 

Not for mine, a 2012 now and a 2010 before that. 3rd and 2nd bars went essentially the same distance as the others, then 1st bar was solid for about half the distance of the higher bars before it started blinking. Then it went another half until DTE fell to 0.

 

interesting. there is another recent thread of a quick drop from 3 to 2 to 1 bar. i don't recall a resolution.

 

agreed, it's an odd situation. my 2012 is almost completely linear. 8 pips, and whichever i fill up from, it's that many gallons. the plug in only has a 10 gallon tank.

 

Yeah that does seem odd. I refill any time the gas gauge falls below half, typically just below half, and in that situation put in around 25 liters, which converts to 6.6 US gallons. I would suspect if I ran it down to one or two pips remaining it would take 8~9 US gallons?

 

I can offer these comments....

Fuel Gauge sensor may be related to the fuel float in the fuel tank.
Could be possible a metal arm attaching to the float was bent upon assembly.
That would alter the fuel level in the tank reported by the gauge.
Need to remove fuel tank to inspect I imagine.

Sulfur from fuel build up on the fuel float assembly.
Not knowing the exact part construction, perhaps the float rides up and down on a stem, with the stem having electrical contacts.
These contacts have said sulfur buildup.
Chevron's Techron concentrate can help reduce or completely eliminate the buildup.

As others mention your gauge reading seems "broken" so it may be a mechanical issue.

Maybe you can adapt to the fuel reading as is?

It is a very bad thing to run a car out of fuel in my opinion, so having two gallons left when the gauge read zero is a good option.
It can also be a good thing to keep the tank near full to reduce rust and moisture.
Yet, with a Hyper-miler stereotype, less fuel equals less weight, less weight equals more miles per gallon.

All above FWIW...good luck.

 

the difficulty will be in proving it to them. you have to go out of state, show up with the blinking pip, get them to go to the gas station with you to see the fill up problem. maybe a video of the last 2 pips will help.

 

For DTE=0, your 7.4 gallons for refill is clearly short. I thinking I'm usually in the vicinity of 8.5 gallons when filling near the 2->1 bar transition, and 9.5 gallons when DTE has just gone to 0.

Read also through just the first post of this too-long thread. It will give you some guidelines for how much fuel should be left that these gauge points.
[WARNING] Running out of gas (Gen III) | PriusChat
If yours is malfunctioning, you might have additional fuel remaining. But don't test it in a way that would leave you stranded or seriously inconvenienced if the fuel isn't there.

 

check out the similar thread 'fuel gauge drops from 2 bars to blinking, very quickly' by new member @BillyGardiner in the gen 3 main forum.
member @kbeck has an interesting post there about a similar problem with a honda.