I have an LV3/6L80E combo that has been working reasonably well up until today, when it all of a sudden says it has a "Transmission Range Malfunction" when trying to access DVT controls for the E92 ECM. It has also had the effect of limiting throttle control, even though there are no DTC's referring to the TCM. I can flash to this TCM, but when I try to Scan, none of the PIDS will validate because it doesn't detect the controller. I've checked for 12v at the trans connector and that is good. Anyone have any quick troubleshooting advice for this? I'm supposed to leave for Drag Week on Saturday, and all was good up until this happened.