I had exactly the same problem with my 2012 at about 85k miles. Reflashing the two modules corrected the problem and it has not returned in the last 10k miles.
It cost me about $220 to reflash these controllers. They did not replace the sensor or cable.
I asked why this was not covered under the Voltec drive train warranty and was told that Software is not a covered component. At some point GM will understand that software is a PRIMARY component in all of their control systems. $220 is very expensive to simply turn off a couple of latches in the firmware.
