Service bulletin TSBENG177B

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	10126427
Published by NHTSA	2017-12-22
Manufacturer's number	TSBENG177B
Manufacturer's date	2017-11-22
NHTSA component	POWER TRAIN

NHTSA's summary

TSB - SERVICE ACTION: 2.4L SHIFT QUALITY & WAKE-UP LOGIC IMPROVEMENT (SA316B) - This bulletin provides the procedure to improve the logic of the Electronic Control Unit (ECU) and Transmission Control Unit (TCU) on some 2018MY Optima (JFa) 2.4L, produced from April 18, 2017 through September 7, 2017, and some 2018MY Sorento (UMa) 2.4L vehicles, produced from March 31, 2017 through October 19, 2017, which may experience an extended crank and/or a shift quality concern, such as a hard downshift, upshift, and/or shift delay.

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

Vehicles listed
KIA OPTIMA	2018
KIA SORENTO	2018

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

Recalls for the same vehicles and component
2018132	2018-03-15. Powertrain

A recall listed here may apply to some of the same vehicles. Only the manufacturer can say whether it applies to one vehicle.

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.
PS750	2023-10-01. Service bulletin. PITSTOP: AWD SYSTEM CONCERN DUE TO TIRE CIRCUMFERENCE - This Pitstop provides information regarding potential concerns with the All-Wheel-Drive (AWD) system due to tire sizes of differing circumference. Some customers may complain of a chatter sensation felt in the drivetrain of the vehicle and/or the failure of drivetrain component(s). A difference in tire size (width, aspect ratio, construction, rim diameter etc.) may be the cause.
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_TRA098	2021-09-03. Service bulletin. TECHNICAL SERVICE BULLETIN: 7-SPEED DUAL CLUTCH TRANSMISSION (DCT) ANTI-JUDDER LOGIC IMPROVEMENT - This bulletin provides the procedure to update the software logic of the Dual Clutch Transmission (DCT) system on some 2016-2020MY Optima (JFa) vehicles produced from August 28, 2015 through June 1, 2020, equipped with Gamma 1.6L T-GDI engine and 7-speed DCT, which might exhibit clutch judder when accelerating from a stop.
TSB_TRA083_R1	2021-09-03. Service bulletin. TECHNICAL SERVICE BULLETIN: 7-SPEED DCT JUDDER INSPECTION AND DUAL CLUTCH ASSEMBLY REPLACEMENT - 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 the procedure to replace Dual Clutch Assembly and upgrade the TCU on some 2016-2020MY Kia vehicles listed in the table below, equipped with the 7 Speed Dual Clutch Transmission (DCT), which might exhibit clutch judder when accelerating from a stop.
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.
TSB_TRA088	2020-03-05. Service bulletin. TECHNICAL SERVICE BULLETIN: TRANSMISSION CONTROL UNIT (TCU) GEAR SHIFT LOGIC IMPROVEMENT - This bulletin provides the procedure to improve the gear shift logic of the Transmission Control Unit (TCU) on some 2018MY Optima (JF, JFa) vehicles produced from April 18, 2017 through July 11, 2018, equipped with 2.0L T-GDI and 2.4L GDI engines, which may harsh downshifts (including 2-1 gear change).
TSBTRA086	2019-12-09. Service bulletin. TECHNICAL SERVICE BULLETIN - PARTIAL REPAIR OF 4WD COUPLING - This bulletin provides the procedure information regarding the partial repair of the Four Wheel Drive (4WD) Coupling Assembly, Pressure Sensor, Actuator Motor or 4WD harness on some 2011-2020 Sportage (SL, QL) and 2013-2020MY Sorento (XMa, UMa) 4WD vehicles for a concern regarding: • Oil leakage from the 4WD coupling assembly • 4WD Malfunction and MIL lamp ON with DTCs • Abnormal noise or vibration while driving
TSBTRA078	2019-07-04. Service bulletin. TSB: TRANSMISSION LOGIC IMPROVEMENT - This bulletin provides the procedure to optimize the logic of the Transmission Control Unit (TCU) on 2017-2018MY Soul (PS) and Forte (YDm) and 2016-2018MY Optima (JFa) vehicles equipped with 1.6T GDI that have one of the following three components replaced: Dual Clutch Transmission (DCT) assembly; Transmission Control Unit (TCU), and Double Clutch Set.The friction material of the double clutch set has been changed and a TCU logic optimization must be performed in order to prevent initial shift shock.