bought a 2013 chevy impala ltz from the auction for a reasonable offer for my son. once i got home inspection was done, found out the battery was not properly installed (bad), blown fuseable link in between battery and alt (replaced). replaced all fuses and relays that i can see that was bad. connected obd2 scanner engine codes u0101 lost communication with transmission control module. replaced tcm, no change, did a little more research, ran a ground to the ground of the can bus of the tcm, it worked (just trouble shooting nothing perm). i found some papers from the previous owners, stating the car was from up north west (salt damage a lot).