TSB - HCU/TCU UPGRADE ? FOR 100MESH SOLENOID - EQUIPPED HYBRID TRANSMISSIONS - This bulletin has been revised to include additional information. This bulletin provides information related to a software upgrade of the Hybrid Control Unit (HCU) and the Transmission Control Unit (TCU) of some 2011-2016MY Optima Hybrid (TF HEV) after replacement of the transmission with improved 100 mesh solenoids has taken place.
