After reading the thread linked below about this issue I unplugged all the cables into my pedal, intending to open it and clean the pedal sensor. Before removing any screws I tried the calibration procedure 1 more time, and this time it succeeded, repeatedly going from 0 to 255. I will assume that the cables had something to do with the issue. Perhaps most likely the external pedal plugged into the Pedal 2 jack?
