I have noticed on my TCH 2009 that when I refuel, the tank average guage hasn't reset twice since I have owned it. Is there a secret to getting it work correctly?

 

try the trip reset... dunno no problems for me

 

I believe the question was about the automatic (and largely, inaccurate) mileage calculator on the dash.
The trip reset button is for miles driven, presumably for manual calculations.

 

Are you filling the tank or maybe just going to half? I have an '09 as well and have had no problems with the MPG display resetting to 0. I fill the tank until the pump shuts off, then give it one more for good measure. When I restart the car, after the gas gauge swings to F the tank MPG resets to 0.

 

Ditto!

 

One time the MPG didn't reset. I turned off the car, opened and closed the gas tank and reset the Nav display. The MPG reset after 30 seconds.

 

I fill the tank with the nozzle set to low auto. Once it shuts off I cap the tank and then pay. After I come back to the car I hold the Trip B in till it reads all zero's. Within seconds after I drive off, the mpg resets itself.

I use Trip A for the oil change, although the MFD alerts me before the 5000 mile oil change is due.