I logged a friends 2008 GMC Sierra last night and after doing a PCM read (high speed checked) the truck started giving a U0101 "Lost comm with TCM" code. The truck will crank but will not shift when driving.
Can anyone give any insight how to correct this issue or if it is possible HPTuners did anything to the PCM and/or TCM? My EIO is not licensed to write to this PCM so I don't see how I could have written anything to the truck.
Please help.