The electric door is part of the evaporative emissions control.

I believe the sensor involved for determining a fill up is the actual fuel gauge sender. My Sienna has a "range to empty" read out as well. It's smart enough to know if you only fill up the tank halfway (ie gas price is high). I don't know about the US, but here the price routinely swings as much as $0.15CAD a liter even over the same day.

For Americans, it would be like seeing gas at $2.80 in the morning, seeing it at $3.20 that evening, next morning it's $3.25, that evening it's $2.75 (unless you stop for milk, then it's up to $3.00), and so forth. It can be very frustrating trying not to feel burned because the day after you fill up it's on a low swing again. Probably one of the reasons I wanted to go TCH.

Two climate control systems, one inside and the other at the tailpipe.

2007 Camry Hybrid (in service June 2006)
FE: 6.67L/100km or 35.3 mpg (6.11L/100km or 38.5 mpg in summer)