What is this error? TCU 130 PID 60 FAIL 02?

I have to put my low fuel economy issues on hold while I track down another random problem.

While bobtailing to get my next load, the Eatob Ultrashift display flashed "F", the CEL came on and the trans wouldn't shift at all, even in manual mode.

While loading, I checked the codes and this one was new: TCU 130 PID 60 FAIL 02.

I checked the Eaton Manual and there is a PID 59 and 61 but no 60. Google showed that a Volvo had this error and it was a rail position sensor or rail position motor.

Does anyone know what this code means for a 2008 Cascadia?

It is easy to reset. I just disconnect the battery and turn the ignition key on and off a few times and the truck works again. Still, if it is a bad rail position sensor, how often do they fail?