Service bulletin 21-AT-013H

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	10201468
Published by NHTSA	2021-09-17
Manufacturer's number	21-AT-013H
Manufacturer's date	2021-08-19
NHTSA component	POWER TRAIN; POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE:SOFTWARE; POWER TRAIN:AUTOMATIC TRANSMISSION

NHTSA's summary

Certain vehicles (listed below) equipped with 7-speed Dual Clutch Transmission (DCT) may exhibit abnormal vibration at low speeds. This bulletin outlines the procedures for diagnosing and replacing the Double Clutch, including a Transmission Control Unit (TCU) software update.

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 ELANTRA	2017, 2018
HYUNDAI ELANTRA GT	2017, 2018
HYUNDAI VELOSTER	2016, 2017

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
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
19-AT-010H	2019-07-01. Service bulletin. This bulletin provides a procedure to transfer pressure data to the ECU/TCU using GDS Mobile. This procedure is necessary to reduce the TCU learning time and improve the shift quality.
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-B7C4X-03	2018-03-12. Service bulletin. If you are servicing an applicable vehicle with a shift lever that is difficult to move, follow the Service Procedure in this bulletin.
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-H7S5M-07	2017-08-17. Service bulletin. Some vehicles with Neutral Control may experience a rough idle in Drive after decelerating to a stop when Neutral Control is enabled. This bulletin provides a diagnosis and repair procedure for this condition. Neutral Control is a fuel efficiency strategy that shifts the transmission into neutral at a stop. The transmission shifts into first gear when the brake pedal is released. Neutral Control is disabled when the shift lever is moved to the Manual Mode position or with the A/C on in some models.
5NP-G5N9M-01	2017-01-25. Service bulletin. IF YOU ARE SERVICING AN APPLICABLE VEHICLE WITH A COMPLAINT OF “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-S9D9P-10	2016-10-18. Service bulletin. THIS BULLETIN PROVIDES INFORMATION ON COMPONENTS, ATTRIBUTES, AND PRECAUTIONS OF THE 7-SPEED DRY-TYPE DUAL CLUTCH TRANSMISSION (DCT).
5NP-H8T3R-10	2016-10-14. Service bulletin. THIS BULLETIN PROVIDES A PROCEDURE TO TRANSFER PRESSURE DATA TO THE PCM USING GDS MOBILE. THIS PROCEDURE IS NECESSARY TO REDUCE THE TCM LEARNING TIME AND IMPROVE THE SHIFT QUALITY.
5NP-B6E2P-10	2016-10-14. Service bulletin. "THE PCM OR TCM CONTAINS LOGIC TO ADJUST SOLENOID DUTY AND LINE PRESSURE AS NEEDED TO COMPENSATE FOR NORMAL CLUTCH WEAR OVER THE LIFE OF THE TRANSAXLE. THIS BULLETIN PROVIDES THE PROCEDURES NECESSARY TO RESET (ERASE) AND RELEARN THE PCM/TCM ADAPTIVE VALUES. AFTER THE FOLLOWING REPAIRS HAVE BEEN COMPLETED, THE PCM/TCM ADAPTIVE VALUES MUST BE RESET IN ORDER TO PROVIDE OPTIMUM SHIFT QUALITY. IF THE PROCEDURE IS NOT PERFORMED, THE TRANSMISSION MAY EXPERIENCE A SHIFT FLARE OR HARSH SHIFT. H REPLACE AUTOMATIC TRANSAXLE OR PCM/TCM H REPROGRAM OR EXCHANGE A PCM/TCM FROM ANOTHER VEHICLE"