2016 Gen4 Prius main odometer mpg jumped up about 4mpg in the last week. 75k miles on car, been tracking around 54mpg, suddenly car is lifetime 58mpg and it ebbs and flows with every trip +/- half gallon mpg. All the other mpg readouts look correct, for example Trip B (used for oil changes) reads steady at 54.2mpg @ 7559 miles. Any ideas why the big mpg monitor would suddenly be fluctuating? No change in driving style, commute, etc.
After digging I found the threads that cover this topic- searched for MPG. Seems the idea is it resets when History is reset. Pretty sure I haven’t done that and wife says same. Also today I had a weird thing where touchscreen was frozen, corrected only after turning off/on. And my AC seems weak. No work done, no change in driving habits. Gremlins? Menehune?
Check the good old 12 volt battery. It can cause all kinds of problems including your infotainment system having problems booting up. If it’s more than four years old I would just replace it.
I noticed something similar with mine and suspected that it is not a full history MPG but a rolling history going back some number of miles or days, etc - which would be weird I admit. But it can be reset just like A/B.
Did you accidentally reset the main odometer, which didn't reset miles, but did reset mpg, as mentioned in prior reply?
Bummer is this is the case. As others discussed in diff threads - Toyota should lock the main mpg. What’s the point of having this one (attached to lifetime odometer) if it’s variable?
The computer has multiple mileage calculators: current trip, trip a, trip b, lifetime. This knowledge is extremely useful. Just press the button on your steering wheel to toggle between the displays.
