TSB - HCU/TCU LOGIC IMPROVEMENT FOR DTC P1744 (400 MESH EQUIPPED TRANSMISSIONS ONLY) - This bulletin provides the procedure to improve the logic of the Hybrid Control Unit (HCU) on some 2011-2012MY Optima Hybrid (TF HEV), produced from February 15, 2011 through December 28, 2012, and both the Hybrid Control Unit (HCU) and the Transmission Control Unit (TCU) on some 2013-2015MY Optima Hybrid (TF HEV) vehicles, produced from January 15, 2013 through March 27, 2015, which may experience a malfunction indicator lamp illumination with DTC P1744. To correct this concern, apply the improved logic to the HCU only (11-12MY) or HCU and TCU (13-15MY) using the KDS ECU Upgrade function as described in this bulletin. For confirmation that the latest reflash has been applied to a vehicle you are working on, verify the ROM ID using the table on page 3 of this bulletin.
