[BYprodriver]

If the battery is disconnected with the fuel level below 1/4 full, the fuel level sensor calibration can be lost. It can be recalibrated with Porsche diagnostic equipment. I think the tank needs to be full to do this.

I learned this when my engine stopped on track at Streets of Willow.
When the engine stopped I looked at the dash & saw the oil warning light on & fuel level @ 1/4. I thought engine lost oil pressure & engine quit as a result. I coasted off track into the infield. after the run session ended I got towed to the parking lot (level ground) Oil level was fine on dipstick & fuel level was fine according to gauge. After a hour agonizing over what damage I had caused to my engine, I realized I wanted to build it anyway so I turned the key & it started & ran fine for about 5 minutes as I drove up & down the parking lot. It ran out of gas again & died.

Don't let the dealership sell you a fuel level sensor without trying to recalibrate what you have. If you do need a new level sensor, consider replaceing the fuelpump also as many are dieing from old age these days.