How do the Fuel Bars work

1 bar is safe, but don't go any lower. i'm not sure how linear the III gauge is, but once you get to know your average mpg's, you'll be able to work backwards as to how much gas you've used and how much is left. i also would like to know when the low fuel warning comes on. in the gen II, there was a quick beep and the last bar would blink.

 

Plenty of threads on this topic, so here we go again...

 

I had one of my scangaugeII programmed as xgauge Flv (fuel left in gas tank). Today while going home (on a slight uphill grade) my 2010 Prius III chirped and the last fuel bar started blinking when Flv=1.3. However, while I was driving home Flv fluctuated from 1.3 to 1.7 . The odometer range says 25 miles...

 

From my experience after 27K and 2.5 years is that one bar not flashing has at least 2 gallons left.

 

The fuel bars are just like the needle on an ordinary gas gauge. They may look more precise, being digital and all, but behind them lies the same crappy float gauge found in all cars. Don't expect a lot of accuracy from any automotive fuel gauge.

Tom

 

When the odeometer range drop to 0 miles my ScangaugeII xgauge Flv was .9 but after that the gauge oscillates back and forth between 1.5 and 0.8...

 

Recently while driving home through a rural area I forgot to gas up where I originally had planned. I noticed the last "bar" flashing in the middle of nowhere at midnight. I knew it was at least 20 miles or more to the next 24 hour gas station. I reduced speed to 55 on cruise. There were a couple of hills I had to get over on the route. I sweated the whole way but finally got to the station. I checked the amount of the fill with the stated capacity in the manual and according to that I had approximately 1 gallon remaining in the tank.

My bitch is there was no audible alarm when it got to one flashing bar. That might have saved me some anxiety.

John

 

I'm pretty sure there is an audio alarm, when there is about 25 miles left. I think it's one beep, maybe a few beeps, not sure. There are still about 2 gallons left.

 

Mine has one short beep that isn't very loud, it's easy to miss if your radio or passengers are loud.

 

If there is an audible alarm I sure missed it ! Is there any way to check this other than running the tank down to 1 flashing bar ?

 

There is, I heard it for the first time on my 2012 Saturday. It is the same as the 2010, a single beep warning when the last pip starts flashing, but some drivers miss it due to loud music or other audio interference. It will also repeat every time the car is restarted.

The most detailed thread, though very long, is Bob Wilson's [WARNING] Running out of gas (Gen III). Some important detail about what really happened is buried very deep in the thread, but basic range is in the base post.