NHTSA ID Number: 11033839
Manufacturer Communication Number: 26-AT-004H TSB
TSB/Document Date: 2026-06-16
Summary
This bulletin provides information related to a Transmission Control Unit (TCU) software update for some vehicles equipped with an 8-speed wet dual clutch transmission (8WDCT). The software update revises the touch point learning variation, improving drivability and judder symptoms. Certain 8WDCTs (indicated by a new part number) received an updated clutch spring. The correct TCU software update must be matched with the correct corresponding 8WDCT hardware, otherwise, drivability concerns may occur. This service procedure should be performed prior to any 8WDCT replacements done for drivability/judder concerns.
GROUP
NUMBER
AUTOMATIC
TRANSMISSION
Technical Service Bulletin
SUBJECT:
DATE
26-AT-004H
MODEL(S)
JUNE 2026
SEE BELOW
DRIVABILITY & JUDDER IMPROVEMENT – 8WDCT TCU UPDATE
FOR VEHICLES WITH 2.0T ENGINES
This bulletin supersedes TSB 23-AT-013H to include an updated title and description, indicating
this service procedure should be performed prior to replacing the dual-clutch transmission for
a drivability concern.
Description: This bulletin provides information related to a Transmission Control Unit (TCU) software
update for some vehicles equipped with an 8-speed wet dual clutch transmission (8WDCT).
The software update revises the touch point learning variation, improving drivability and judder
symptoms. Certain 8WDCTs (indicated by a new part number) received an updated clutch spring. The
correct TCU software update must be matched with the correct corresponding 8WDCT hardware,
otherwise, drivability concerns may occur. This service procedure should be performed prior to any
8WDCT replacements done for drivability/judder concerns.
Applicable Vehicles:
Model Year
Model
2022 & Later
Elantra N (CN7 N)
2022 – 2023
Kona N (OS N)
2021 – 2022
Veloster N (JS N)
Theta 2.0T
Parts Information –
BEFORE Improvement 8WDCT:
Model
Event
No.
Elantra N
(CN7 N)
900
Kona N
(OS N)
899
Veloster N
(JS N)
898
Trans
Type
SBC,
2WD
+
ELSD
8WDCT Assembly Part Number
Remarks
T/M Assembly
Reman
430F0-2N071
N/A
w/ TCU
43000-2N070
43000-2N070RM
w/o TCU
430F0-2N061
N/A
w/ TCU
43000-2N060
43000-2N060RM
w/o TCU
430F0-2N031
N/A
w/ TCU
43000-2N002
43000-2N002RM
w/o TCU
TCU
Calibration ID
WCN7T20XXX900NS4
WOSNT20XXX900NS6
WJSNT20XXX900NS7
NOTE: SBC = Shift By Cable
Circulate To: General Manager, Service Manager, Parts Manager, Warranty Manager, Service
Advisors, Technicians, Body Shop Manager, Fleet Repair
DRIVABILITY & JUDDER IMPROVEMENT – 8WDCT TCU UPDATE
FOR VEHICLES WITH 2.0T ENGINES
SUBJECT:
SST Information:
Tool Name
Tool Number
VCI 3
G0VHNNN06
Figure
Ordering Information
Website:
https://hyundaiessentialtools.com/
Email:
[email protected]
VCI 2
Phone: 1-855-763-9199
Hours: 7 AM – 7 PM CST
G1XDDMN001
NOTE: VCI 2 can NO longer be ordered but can be used for the updates in this TSB.
GDS Information:
Model
System
Elantra N
(CN7 N)
Kona N
(OS N)
AT
Event Number*
Description
900
CN7 N THETA 2.0T SOL. VALVE OPERATING
FREQUENCY LOGIC IMPROVEMENT(TCU)
899
OS PE N THETA 2.0T SOL. VALVE OPERATING
FREQUENCY LOGIC IMPROVEMENT(TCU)
Veloster N
JS N THETA 2.0T SOL. VALVE OPERATING
898
(JS N)
FREQUENCY LOGIC IMPROVEMENT(TCU)
(*or use a later available event listed in the GDS DCT Update screen if one is available.)
Warranty Information:
Model
Op. Code
Elantra N
(CN7 N)
Kona N
(OS N)
Operation
Op.
Time
Causal Part
Nature
Code
Cause
Code
S21
ZZ3
954A1-2N510
954A0F02
TCU Software Update
(BEFORE improved
8WDCT) +
Vehicle Calibration
0.7
M/H
954A1-2N410
Veloster N
954A1-2N020
(JS N)
NOTE 1: Normal warranty applies.
NOTE 2: Submit claim on Claim Entry Screen as “Warranty” type.
NOTE 3: This TSB includes repair validation photo(s). Op times include VIN, mileage, and photo
capture of the ECU Update “Success” result screen as outlined in the Digital Documentation Policy.
NOTE 4: If any part(s) not subject to this TSB are found in need of replacement while performing the
repair procedure, and the affected part(s) are still under warranty, the dealer may submit a separate
claim using the same repair order. If the part(s) not subject to this TSB are out of warranty coverage,
the dealer has the option to submit a PA Request for goodwill consideration on a case-by-case basis.
TSB #: 26-AT-004H
Page 2 of 10
SUBJECT:
DRIVABILITY & JUDDER IMPROVEMENT – 8WDCT TCU UPDATE
FOR VEHICLES WITH 2.0T ENGINES
ROM ID Information:
Model
Elantra N
(CN7 N)
Kona N
(OS N)
Veloster N
(JS N)
Event
System
900
899
898
TSB #: 26-AT-004H
AT
TCU
Part Number
ROM ID
Current
Latest
954A1-2N510
WCN7T20XXX800NS0
WCN7T20XXX800NS1
WCN7T20XXX832NS2
WCN7T20XXX900NS3
WCN7T20XXX800NS0
WCN7T20XXX800NS1
WCN7T20XXX832NS2
WCN7T20XXX900NS4
954A1-2N410
WOSNT20XXX730NS0
WOSNT20XXX730NS1
WOSNT20XXX800NS2
WOSNT20XXX800NS3
WOSNT20XXX832NS4
WOSNT20XXX900NS5
WOSNT20XXX900NS6
954A1-2N020
WJSNT20XXX700NS0
WJSNT20XXX700NS1
WJSNT20XXX700NS2
WJSNT20XXX730NS3
WJSNT20XXX800NS4
WJSNT20XXX832NS5
WJSNT20XXX900NS6
WJSNT20XXX900NS7
Page 3 of 10
SUBJECT:
DRIVABILITY & JUDDER IMPROVEMENT – 8WDCT TCU UPDATE
FOR VEHICLES WITH 2.0T ENGINES
Service Procedure:
DIGITAL DOCUMENTATION
This TSB includes repair validation photos. Refer to the latest Warranty Digital Documentation
Policy for requirements.
NOTICE
Applying the recommended torque to all fasteners is essential to reduce potential issues from
occurring after the service procedure.
Table of Contents
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TSB/Document ID: 26-AT-004H TSB
Replacement Service Bulletin Number:
MFR Communication Date: 2026-06-05
MFR Internal Campaign ID/Software Version:
Communication Type: Service Bulletin/Repair Instructions
NHTSA Components: POWER TRAIN
MFR Component System:
MFR Component Subsystem:
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