TSB: COMBINATION TSB/SERVICE ACTION: IDLE STABILITY & SHIFT QUALITY IMPROVEMENT (SA294) - This bulletin provides the procedure to improve the logic of the Electronic Control Unit (ECU) and the Transmission Control Unit (TCU) on some 2016MY Optima (JFa) vehicles, produced from September 3, 2015 through November 22, 2016, which may experience a vibration and/or hesitation when releasing the brake pedal after coming to stop, and/or a shift quality concern, such as a harsh downshift, upshift, and/or shift delay. To correct this concern, apply the improved logic to the ECU and TCU using KDS download as described in this bulletin.
