TSB: SERVICE ACTION: VOLTAGE REGULATOR PERFORMANCE ENHANCEMENT (SA278) - This bulletin has been revised to include additional information. This bulletin provides the procedure to increase the torque on the voltage regulator screws on some 2017MY Sorento (UMa), produced from October 3, 2016 to January 24, 2017, and 2017MY Optima (JFa) vehicles, produced from October 3, 2016 to January 26, 2017, which may experience low battery voltage or a no-start condition.