TSB: SERVICE ACTION: TCU UPGRADE ? DRIVING PERFORMANCE IMPROVEMENT (SA246) - This bulletin provides information related to the Transmission Control Unit (TCU) software upgrade for some 2017MY Sorento (UMa) 3.3L GDI vehicles produced from April 6, 2016 to October 20, 2016 for a logic improvement. To apply the improved logic, the TCU should be reprogrammed using the GDS/KDS download, as described in this bulletin.