They have ran several picoscopes to my understanding. They (GM) actually wrote a new calibration For the vehicle that did seem to help the shake problem. I’m thinking this Truck has a BCM issue. The other morning I came out to a dead vehicle. Had to jump it off. Drove it to the dealer. It had multiple codes in it. Steering shake came back on th trip to the dealer. Then after the codes were cleared it seemed to be fine. They replaced the battery per my request so at least something would be done. Weird thing too is that all of my engine hours got cleared out. Trip reset to the vehicle miles. Strange!! Anyway I’m done with it. Going to replace it.