Just bought the 2021 20th Anniversary Edition!

My understanding that this sound comes from a speaker under the hood and it's as easy as unplugging it or snipping its wire...

 

It sounds like you've already checked every possible display option and not found it. I have not been able to find it on our 2017 either, and am convinced it doesn't exist. Possibly you could use the trip odometer to keep track of miles since last fill up, but I never bother. Distance to empty (even if it's only an estimation) would also be useful information, but I do not believe that exists on these cars either (I haven't been able to find it on either our Gen 2 or the Gen 4).

 

Au contraire, mon frere. Although I am not sure it is documented in the manual, the 2nd Info screen on our 2007 (those on the right of page 167 of the Owners Manual) always shows the number of miles since the last fill up, without any intervention on our part. I have not seen that feature on any other car, and find it to be quite useful, although perhaps not as useful as a Distance to Empty estimate.

 

Consumption screen on the MFD on Gen 2 showed the miles since last fill up. In a way, it was like having three trip meters. I miss that. Now I use trip A for daily miles (or an entire trip if it's more than a day) and trip B for the tank.

Edit to add: the distance reset automatically when you filled the tank. I don't recall how much it took to reset it, but I'd guess it's 3 gallons since that's what it takes to make the gas gauge register the change. At least I think the 2005s did. That was a while ago. I know the '07 did.

 

Sometimes on long road trips I can pull over for other reasons beyond getting gas and trick my 2007 into thinking I filled the tank and it will inadvertently reset when it's not suppose to. Also seems the reset can happen with any amount of gas, not just filling the tank all the way.

 

Does opening the fuel filler door reset it? I've never tested that, but I guess it would make sense.

 

From the 2007 OM referring to the picture in post #6:

No mention of the door. But I see that it's not 3 gallons as I was remembering. It's 2.6.

 

Hmm, I skipped over that apparently, and strangely enough, that's not the way it works on our car. If I'm reading that correctly, I would expect the MPG shown on that screen to only apply to the current tank. On our car, the number of miles shown on the bottom right resets with each fill up, but the MPG is life-to-date (or at least life-to-date since the reset button has been pressed or the 12V has been disconnected). Is our car unique?

 

I don't know what every model year did, but our 2005s and our 2007 reset the gas mileage on that screen whenever the miles reset.

 

That is interesting. So our car is unique. From what you are saying, when you fill your tank, before you pull out of the gas station, if the ICE on your cars starts up, that display will show 0 MPG, correct? Then when you get on the highway, you will see it slowly increasing until it gets to its approximate highway MPG? On our car that MPG stays the same for days on end. If we do a lot of highway driving, I will see it tick up a tenth or 2. Now that it's been driven around NYC for the last couple of months in the cold, mostly on local streets, we've lost probably a couple of MPG on what I'm seeing as the Life-to-Date average. The only customizations that I'm aware of on our car are a Coastaletech LockPick device between the factory Navigation DVD drive and the MFD to allow limited functionality of the Navigation system while the car is in motion and an additional antennae for satellite radio reception. I wouldn't expect that either of those would change the behavior of the Energy Monitoring system. Strange.

 

Not what I said. I refer you back to the quote from the owners manual on post #10. Hit the reset or add more than 2.6 gallons and the car resets the average fuel consumption at least on a 2007 MY Prius. I suppose if you just sat at the pump with the car in READY, waited for the number to rest (it took a few seconds, as I recall), and forced the ICE to run, it would say 0 MPG till you got moving. I never had time for that stuff or reason to force the engine to run after a fill up.

What year car are you talking about, btw?

 

Ours is a 2007. To further clarify, putting more than 2.6 gallons in your tank has the same effect as pressing the Reset button on the MFD, wiping out all the prior MPG history? I may never actually have pressed the Reset button, but I'm assuming that's what it would do, based on what I saw when I had disconnected the 12V on 2 occasions. If I remember correctly, I believe I saw the MPG on the display start at a very low number and gradually increase to a more reasonable value as the car warmed up and accumulated highway miles and it has stayed at what I consider the Life to Date value since.

It is hard to believe that our car acts differently than everyone else's, but I know of at least one other behavior that seems unique (unrelated I'm sure). After changing the HID headlight bulbs the first time after I bought the car, I found the factory fog lights stay on whenever the headlights are turned on, the fog light switch does nothing. I'm pretty sure the fog light switch could turn the fog lights on and off before I changed the headlight bulbs. Another head-scratcher.

 

Just curious if you've done any digging around to figure out what number yours is in the 2020 limited line of production. I'm trying to figure mine out but the ending of the VIN gives no clue (VIN ends in 129767).

We own two of only 2020 made. Just curious of production order. Would be cool to have number 4 or 5 or something low.