Factory Tank Average Gas Mileage Calculation Question

Out of simple curiosity, does anyone know how the truck 'knows' that I have put fuel into the tank, so that it begins a new Tank Average MPG determination?

Does it register that I have removed the gas cap, and thus infer that I have refilled the tank?

Is there a gas tank scale that, if it sees the weight increase, infers that I have refilled the tank?

What prompted my question is that I recently added only one gallon of gas from a can, and the truck started recalculation my tank average MPG.

Anyone have any insight?

Thanks................... Frank

 

I have had it where I added just a gallon or two and it didn't reset (I was curious), so there has to be a sensor in the tank and I was just filling the fill tube.

 

Thank you. That's what I wanted to know.

Frankly, I'm surprised that this method can work, since gas is always sloshing back and forth, and the one gallon that I added has to be nearly perceivable by a float mechanism. But I guess that this is the simplest way to do it.

Thanks for your help.................... Frank

 

Its most likely a sensor placed in the tank. Its probably on a bobble style to know when it moves.

 

Float in tank connected to sending unit

 

There used to be a BMW mechanic on here, he had a car hooked up to a diagnostic unit and the car showed the date that gas was put in and also showed the grade, no idea if our Trucks go that deep.