Since I seem to be in a ranting mood, but at the risk of tarnishing my Prius-evangelism mindset, I must confess that there is one thing about the Prius that disappoints me. It has a wildly inaccurate digital gas gauge (notoriously so, since this is a common topic of discussion on Prius listservs and among Prius owners). What’s worse is that the direction and magnitude of the inaccuracy aren’t consistent, so there’s no really no way to use the gas gauge at all to determine when to fill up.
When the tank is full, the Prius shows ten lighted boxes along a continuum from empty to full. As the tank empties, the boxes theoretically begin to go dark. However, sometimes the entire set of ten remains lit for a while and then very quickly a number of them will darken in succession. Other times the entire set begins to darken quickly, getting all the way to a single remaining lit box even though there’s still gas–sometimes a considerable amount–in the tank.
Before my trip to visit my mother this weekend, for example, the boxes had darkened so that only a single one remained lit, so I went ahead and filled up, even though my mileage suggested that I had several gallons remaining. I was able to put something over 9 gallons in the tank, which allegedly holds between 11 and 12. This morning, however, after my trip there and back, the gauge still showed just short of half of the boxes lit; but on the mile-and-a-half commute to work, three of the four lit boxes darkened in a matter of minutes, leaving just one still lit. At the end of the day, when I got in the car, that single box began flashing, and the computer screen flashed an ominous–albeit politely so–“Please Add Fuel,” neither of which I’d yet seen. So, worried that I might run out of gas, even though again my mileage suggested I shouldn’t be anywhere near empty, I filled up on the way home. The tank only accepted about 7-1/2 gallons, meaning it still had 4, which would have taken me at least 160 miles.
I start to panic, though, when the gauge goes nearly dark–and especially today when the car started sending me messages about needing fuel–because the manual is very unequivocal about not driving the car without gas, even though it does have a battery-powered engine as well as a gas-powered one, promising dire consequences if this warning is unheeded. Even when I know I certainly have gas remaining, and probably a generous amount, I worry about running out of gas.
You’d think a car otherwise so technically sophisticated would have a gas gauge more reliable than casting bones or reading tea leaves.