Situation- Recently purchased a 2012 Sierra 3500 Denali. Truck was tuned with a PPEI autocal. The previous owner had swapped in 4.56 gears about 50k miles ago. This set off the ABS light and warning for obvious reasons. Previous owner didnt care about the light and drove it this way for 50k miles. I wanted to correct this issue. I had the "tuner" at the shop where I work use HP Tuners to try and change the gearing in the pcm. That failed and now the truck will not start or communicate with the autocal. Gives a U0100 no comm. code.
Can the pcm be recovered with a proper flash? Is there anyone out there who can do this? Should I buy a used/Ebay pcm and start over? Then I will.need a new VIN licence for the autocal. Truck is already deleted so no.one seems.to want to help me. Even with just a stock file to start with. Maybe I'm just not looking in the right places? Any guidance would be appreciated