Not necessarily true.Can you explain what "actual" is? It's my understanding that all mpg measurements are estimates, with the dash/trip display being the most accurate on a stock vehicle.
When It Comes to Mileage, Cars Tell the Truth | Final Inspection
The ECU calculates MASS of fuel injected. It then uses a density conversion to calculate VOLUME of fuel used for your dash display. Density will vary with temperature and brand, among other things. The actual volume of fuel used it how much you put into the tank via the gas pump.
Long term, using the pump volume and odometer mileage is the standard for vehicle fuel economy. Within a tank, I'd say the dash output is an excellent estimate for fuel used when comparing different routes or speeds. Comparing tanks back-to-back, both the dash and pump have errors. The dash can't compensate for the fuel density change and the pump won't always refill to the same level.
For the last 12 tanks on my Prius v (waifu drives the 4Runner), the dash mpg has averaged 6% higher than the pump mpg. Min of 3.2% higher, max of 9.5% higher.
Attachments
Last edited:
