Service bulletin TSBTRA079

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
Type	Service bulletin
NHTSA id	10144237
Published by NHTSA	2018-09-10
Manufacturer's number	TSBTRA079
Manufacturer's date	2018-08-13
NHTSA component	POWER TRAIN

NHTSA's summary

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.

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Transmission and driveline

Trouble codes named

P1744

Vehicles listed
KIA OPTIMA HYBRID	2013, 2014, 2015 (the catalog's model; the bulletin names a series or trim of it)

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Other bulletins for the same vehicles and component
TSB_TRA046_R5	2025-04-23. Service bulletin. TECHNICAL SERVICE BULLETIN: TRANSMISSION FLUID APPLICATION GUIDE - This bulletin has been revised to include additional information. New/revised sections of this bulletin are indicated by a black bar in the margin area. This bulletin provides information relating to the correct transmission fluid type and fill quantity requirement for each Kia model. A flush is required ONLY when a transmission is replaced, and the transmission oil cooler is transferred to the new transmission.
TSB_TRA046_R4	2024-06-04. Service bulletin. This bulletin provides information relating to the correct transmission fluid type and fill quantity requirement for each Kia model. A flush is required ONLY when a transmission is replaced.
TSB_TRA046_R3	2022-12-06. Service bulletin. TECHNICAL SERVICE BULLETIN: TRANSMISSION FLUID APPLICATION GUIDE - This bulletin provides information relating to the correct transmission fluid type and fill quantity requirement for each Kia model. A flush is required ONLY when a transmission is replaced, refer to applicable vehicles in the chart starting on page 2.
TSB_TRA059	2020-12-04. Service bulletin. TECHNICAL SERVICE BULLETIN: HCU/TCU UPGRADE - FOR 100 MESH SOLENOID EQUIPPED HYBRID TRANSMISSIONS -This bulletin provides information related to a software upgrade of the Hybrid Control Unit (HCU) and the Transmission Control Unit (TCU) of some 2011-2016 MY Optima Hybrid (TF HEV) vehicles after replacement of the transmission with improved 100 mesh solonoid filters has taken place. To apply the improved logic, the HCU/TCU should be reprogrammed using the GDS/KDS download, as described in this bulletin.
TSB_TRA046_R1	2020-05-05. Service bulletin. TECHNICAL SERVICE BULLETIN: - TRANSMISSION FLUID APPLICATION GUIDE - This bulletin has been revised to include additional information. This bulletin provides information relating to the correct transmission fluid type and fill quantity requirement for each Kia model. A flush is required ONLY when a transmission is replaced, refer to applicable vehicles on page 2. Refer to the shop manual on KGIS for the specific Kia model for the correct transmission fluid check/fill procedures.
VPI1802_TSB_R2	2018-10-09. Service bulletin. PRODUCT IMPROVEMENT CAMPAIGN (PI1802) - TSB - KNOCK SENSOR DETECTION SYSTEM - ECU LOGIC IMPROVEMENT (PI1802) - This bulletin provides information related to a software update to the Engine Control Unit (ECU) to install the Knock Sensor Detection System (KSDS) in order to protect the engine from excessive connecting rod bearing damage.
TSBTRA068_CLOSED	2018-09-10. Service bulletin. TSB: HCU/TCU LOGIC IMPROVEMENT FOR DTC P1744 (400 MESH EQUIPPED TRANSMISSIONS ONLY) - TSB TRA068 CLOSED. REFER TO TSB TRA079/SA351
VPI1802_QA	2018-08-06. Service bulletin. Q & A - This document is the Q & A for the new Product Improvement Campaign to provide information regarding a software update to the Engine Control Unit (ECU) to protect the engine from excessive connecting rod bearing damage.
VPI1802_DSM	2018-08-06. Service bulletin. DEALER SERVICE MANAGER NOTICE - This notice advised the dealer service manager of the new Product Improvement Campaign to perform a software update to the Engine Control Unit (ECU) to protect the engine from excessive connecting rod bearing damage.
TSBTRA059_R4	2018-05-14. Service bulletin. 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.