TSB: SERVICE ACTION: HCU/TCU LOGIC IMPROVEMENT FOR DTC P1744 (400 MESH EQUIPPED TRANS) (SA351) - This bulletin provides the procedure to improve the logic of the Hybrid Control Unit (HCU) and the Transmission Control Unit (TCU) on some 2013-2015MY Optima Hybrid (TF HEV) vehicles, produced from September 27, 2012 through September 5, 2014, which may experience a malfunction indicator lamp illumination with DTC P1744. To correct this concern, apply the improved logic to the HCU and TCU using the KDS ECU Upgrade function as described in this bulletin.
