Service bulletin 21-AT-014H

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	10201469
Published by NHTSA	2021-09-17
Manufacturer's number	21-AT-014H
Manufacturer's date	2021-08-19
NHTSA component	POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE:SOFTWARE; POWER TRAIN

NHTSA's summary

Certain vehicles (listed below) equipped with 7-speed Double Clutch Transmissions (DCT) may exhibit abnormal vibration at low speeds. This bulletin outlines the procedures for diagnosing clutch judder, updating the Transmission Control Unit (TCU) with revised logic, and/or replacing the Double Clutch.

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, Automatic transmission, Transmission control module

Vehicles listed
HYUNDAI SONATA	2015, 2016, 2017, 2018
HYUNDAI TUCSON	2016, 2017, 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
16V628000	2016-08-30. ELECTRICAL SYSTEM:SOFTWARE; POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM/PCM/TECM)

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
19-AT-018H	2019-09-30. Service bulletin. If you are servicing an applicable vehicle with a ?Check Engine? light on and one or more of the DTC listed below, follow the repair procedure and replace the related input/output speed sensor and oil pressure harness.
19-AT-015H	2019-09-30. Service bulletin. If you are servicing an applicable vehicle with a ?Check Engine? light on and one or more of the DTC listed below, follow the repair procedure and replace the related solenoid and oil pressure harness
5NP-P5L7D-05	2018-05-21. Service bulletin. If you are servicing a vehicle with a harsh and/or delayed shift, use the GDS as shown in the Service Procedure to measure shift engagement time.
5NP-L2K7X-05	2018-05-21. Service bulletin. If you are servicing a vehicle with a harsh and/or delayed shift, use the GDS as shown in the Service Procedure to measure shift engagement time.
5NP-R6Y5M-01	2018-01-16. Service bulletin. This bulletin provides information related to the Engine Control Module (ECM) and Transmission Control Module (TCM) software updates for certain 2018MY SONATA, equipped with 2.0L turbo engine and 8 speed automatic transmission. These vehicles may experience Malfunction Indication Light illumination with any of the following DTC(s) below: ? P219C: Cylinder #1 Imbalance Error ? P219D: Cylinder #2 Imbalance Error ? P219E: Cylinder #3 Imbalance Error ? P219F: Cylinder #4 Imbalance Error ? P0731: Gear 1 Incorrect Ratio
5NP-Z6F3A-11	2017-11-14. Service bulletin. Before installing an automatic transmission, check the depth of the torque converter in the case to confirm the torque converter is fully installed in the transmission. If this is not done, the oil pump may be damaged.
5NP-P9A3V-12	2017-10-15. Service bulletin. Eco, Sport, and Limited trim 2016 Hyundai Tucsons are equipped with a 7-speed EcoShift® Dual Clutch Transmission (DCT). In specific operating conditions, the transmission clutch application logic can result in a delayed engagement when accelerating from a stop. If the accelerator pedal is steadily depressed for approximately 1.5 to 2 seconds, the vehicle will begin to accelerate and normal driving is resumed. However, if the accelerator pedal is repeatedly cycled, the vehicle will not accelerate. The inability to move the vehicle in traffic may increase the risk of a crash. Also accompanying with the software are updates for the following: ? A slight hesitation at low speeds that can be experienced in certain driving conditions. This update improves the low speed engine and transmission response. ? Malfunction indicator light illuminated with DTC P0128 - Coolant Thermostat - Coolant Temp Below Thermostat Regulating Temperature.
5NP-B9K3N-10	2017-10-12. Service bulletin. Some Sonata Hybrid (LF HEV) vehicles may experience a small oil leak from the electric oil pump (EOP) seals. If so, follow the Service Procedure in this bulletin to inspect and repair the oil seals between the transmission and EOP. No drivability issues are associated with this condition.
5NP-B6Z4E-10	2017-10-12. Service bulletin. The 2018 Sonata (LFA) 2.0T is equipped with an 8-speed transmission. Do not replace the transmission for any of the solenoid DTC listed below. Instead, follow the Service Procedure on Page 2 and replace the related part.
5NP-B6N5A-04	2017-08-10. Service bulletin. This bulletin provides the procedure to update both the ECM (Engine Control Module) and the TCM (Transmission Control Module) on some 2016 and 2017 Hyundai Tucsons equipped with a 7-speed EcoShift® Dual Clutch Transmission (DCT). The update will address: ? A slight hesitation at low speeds that can be experienced in certain driving conditions. This update improves the low speed engine and transmission response. ? Malfunction indicator light illuminated with DTC P0128 - Coolant Thermostat - Coolant Temp Below Thermostat Regulating Temperature.