May have ran it out of gas today ?

[sas0611]

Today I ignored the first and maybe the second low fuel warning alert. I then was sitting in a parking lot with windows open and car in the 'ready' / on state. The only thing running was the radio. In the middle of enjoying the nice weather I see the Triangle Master Warning light, the VSC indicator light and probably some other lights thrown in for good measure. I didn't take time to note them all. I shut the car off.

I can say without a doubt that the minute or so leading up to the event was seemingly uneventful. The pack had discharged to a level requiring the ICE to kick on and it did. I watched it bring the pack level back up to about 3 blue bars when the dreaded triangle showed up on the dash. I was literally a half block from a gas station so after the panic subsided I restarted the car and using electric only made my way to the pump and filled it up. It took 10.8 gallons before the nozzle shut off.

When I started the car up after filling it the dash was clear of any warnings.

I am wondering if there could have been any damage. I doubt it since the light was only illuminated for no more than 30 seconds before refilling ? I have to believe that the gas tank didn't run dry since the ICE was running to recharge the pack when the triangle light came on. If the ICE was running there must have been gas in the car ? The specs say the tank capacity is 11.9 gallons. My fillup only required 10.8 gallons so there must have been another 1.1 gallons in the car still (assuming the bladder was not giving me weird levels).

Can any one suggest whether there should be cause for alarm or a need to visit the dealership to check fault codes ? I have to believe that the master warning came on prior to allowing the car to damage itself and this is part of the design as an attempt to actually grab the drivers attention. The car drives fine no warning lights remain on.

Thanks in advance. BTW ... I'll never even come close to 1 blinking pip again. I think I got of easy this time.

[ksstathead]

Fill at 2 pips seems to be the mantra of safety. You never know capacity or DTE with the bladder. I think you'd be ok. Running EV from 3 blue bars wouldn't last long, but it was only half a block. So I doubt you depleted the pack beyond normal range.

[richard schumacher]

Doing that repeatedly will reduce battery life, but your one short episode is negligible and not worth worrying about. And No, you did not have 1.1 gallons left in the tank. Thanks to the bladder the tank was empty (disregarding a possible few teaspoonfuls that were unavailable in any case).

[yardman 49]

The fuel pump should be in the gas tank. Possibly it has a sensor indicating that it had pumped the tank down enough to hit air? Maybe that was enough to trigger the MWL, even though there was enough pressure in the gas line to keep the ICE running?

[kimgh]

Originally Posted by sas0611

Today I ignored the first and maybe the second low fuel warning alert. I then was sitting in a parking lot with windows open and car in the 'ready' / on state. The only thing running was the radio. In the middle of enjoying the nice weather I see the Triangle Master Warning light, the VSC indicator light and probably some other lights thrown in for good measure. I didn't take time to note them all. I shut the car off.

I can say without a doubt that the minute or so leading up to the event was seemingly uneventful. The pack had discharged to a level requiring the ICE to kick on and it did. I watched it bring the pack level back up to about 3 blue bars when the dreaded triangle showed up on the dash. I was literally a half block from a gas station so after the panic subsided I restarted the car and using electric only made my way to the pump and filled it up. It took 10.8 gallons before the nozzle shut off.

When I started the car up after filling it the dash was clear of any warnings.

I am wondering if there could have been any damage. I doubt it since the light was only illuminated for no more than 30 seconds before refilling ? I have to believe that the gas tank didn't run dry since the ICE was running to recharge the pack when the triangle light came on. If the ICE was running there must have been gas in the car ? The specs say the tank capacity is 11.9 gallons. My fillup only required 10.8 gallons so there must have been another 1.1 gallons in the car still (assuming the bladder was not giving me weird levels).

Can any one suggest whether there should be cause for alarm or a need to visit the dealership to check fault codes ? I have to believe that the master warning came on prior to allowing the car to damage itself and this is part of the design as an attempt to actually grab the drivers attention. The car drives fine no warning lights remain on.

Thanks in advance. BTW ... I'll never even come close to 1 blinking pip again. I think I got of easy this time.

General aviation pilots have a concept called Maximum Usable Fuel (MUF). I have concluded from several threads on this forum that the MUF of a Prius is 10 gallons. I estimate remaining fuel not by looking at the number of pips, but by dividing the number of miles since the last tank by the currently displayed average MPG. I think that's fairly safe, and I've NEVER put 10 gallons back in (though I've come close a time or two).

Kim

[sas0611]

Thanks for all the replies. I gather from the posts that the primary concern on an out of gas situation is depleting the 'pack' to damaging levels. I am sure I came nowhere near that scenario. As always, I appreciate the intelligent and thoughtful replies. It's reassuring to know that when I do stupid things to my prius, I can always get quick and correct information on just about any prius topic.This group is remarkable.

Again ... to all that have responded in the past to my/our posts and all that will undoubtedly be there to help me/us all in the future... THANK YOU !

[DaveinOlyWA]

well if all the warning lights are off, monitor its mileage for a while to see if any change in performance occurs. if not, forget about it. if so, take it in.

more than a few have reported similar situations when some simply shut it down, waited a few minutes, started back up and were able to drive to a nearby station to fill up. sometimes i wonder if the tank is low and gas sloshing around caused the pump to suck a little air causing the idiot light show.

either way, i would not make a habit of it. putting in nearly 11 gallons most likely means you were empty

[toxicity]

At some point, when the gas gets low enough, the last pip on the gas gauge blinks; and a message comes up on the MFD saying "Add fuel", and I believe the big red triangle comes up too. When that happens, from what I have determined, you have half a gallon remaining; that should have been a good hint to go get gas. Don't let it run out!

[auricchio]

Originally Posted by kimgh

General aviation pilots have a concept called Maximum Usable Fuel (MUF).

And even then, we were taught that one only trusts the gauge when it says empty.

[qbee42]

No real worries, just don't make a habit out of it. Chalk this one up as a cheap lesson.

Tom