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Service bulletin 21-01-064H

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)
TypeService bulletin
NHTSA id10204246
Published by NHTSA2021-12-09
Manufacturer's number21-01-064H
Manufacturer's date2021-11-16
NHTSA componentENGINE AND ENGINE COOLING

NHTSA's summary

This bulletin provides information related to an Electronic Control Module (ECM) software update to revise control logic for completion of OBD-II Fuel System Readiness Monitor diagnosis.

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

Engine

Vehicles listed
HYUNDAI ELANTRA2017, 2018, 2019

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

Recalls for the same vehicles and component
20212522021-04-28. Engine
21V3010002021-04-28. ENGINE

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
26-EM-016H TSB2026-10-14. Service bulletin. Some vehicles equipped with internal combustion engines may exhibit higher-than-expected engine oil consumption. This bulletin outlines the combustion chamber cleaning procedure for vehicles diagnosed with this condition. All internal combustion engines consume some engine oil during normal operation, depending on driving conditions and mileage, and this procedure should only be performed when deemed necessary based on inspection and diagnosis of the vehicle as outlined in TSB 26-EM-015H, Engine Oil Consumption – Inspection & Repair Guidelines, or the latest revision.
26-EM-015H TSB2026-10-13. Service bulletin. Certain vehicles equipped with internal combustion engines may exhibit higher-than-expected engine oil consumption. This bulletin provides the inspection and repair procedures for vehicles exhibiting this condition. All internal combustion engines consume engine oil as part of normal engine operation. Oil consumption rates may vary based on mileage, operating conditions, driving habits, and maintenance history. Hyundai recommends following the prescribed maintenance schedule and periodically checking the engine oil level using the dipstick to maintain proper engine oil level.
9D3 OL2026-09-11. Service campaign. Hyundai has become aware that your Hyundai Elantra equipped with a 2.0 ATK engine may have been incorrectly updated with Cylinder Noise Detection System (CNDS) software intended only for Korean-built Elantra vehicles and may not meet specifications.
26-01-039H DN2026-08-15. Service campaign. Certain Elantra (ADA) vehicles may have been incorrectly updated with Cylinder Noise Detection System (CNDS) software that can set DTC P132700; this software was intended only for Korean-built Elantra (AD) vehicles. In addition, the California Air Resources Board has determined that these vehicles may be releasing air pollutants which exceed Federal and California standards.
26-01-039H TSB2026-08-15. Service campaign. Certain Elantra (ADA) vehicles may have been incorrectly updated with Cylinder Noise Detection System (CNDS) software that can set DTC P132700; this software was intended only for Korean-built Elantra (AD) vehicles. This bulletin provides instructions to perform a software update for the Engine Control Module (ECM) to revert to the original ROM ID, apply the emissions label under the hood, and provide the vehicle owner with Proof of Correction.
23-EM-005H2023-12-15. Service bulletin. This bulletin provides important checkpoint guidelines when performing engine oil and filter change services.
22-EM-010H2022-08-05. Service bulletin. Follow the guidelines outlined in this bulletin to inspect and clean or replace certain components of the engine intake system accordingly during engine short block or sub-assembly replacement.
22-EM-008H2022-06-10. Service bulletin. Hyundai is conducting a service campaign 974 to enhance the knock sensor logic with the Cylinder Noise Diagnostic System (CNDS) software update. CNDS is to detect abnormal cylinder wall scuffing or noise of the engine block before potentially severe engine damage occurs. If abnormal noise is detected, the Malfunction Indicator Lamp (MIL) will blink continuously. In addition, DTC P1327 will be recorded in the ECM.
22-01-043H2022-06-10. Service bulletin. Hyundai is conducting a service campaign to enhance the knock sensor logic with the Cylinder Noise Diagnostic System (CNDS) software update. CNDS is to detect abnormal cylinder wall scuffing or noise of the engine block before potentially severe engine damage occurs. If abnormal noise is detected, the Malfunction Indicator Lamp (MIL) will blink continuously. In addition, DTC P1327 will be recorded in the ECM.
968DBP202111162021-12-09. Service bulletin. This update includes information related to Electronic Control Module (ECM) software to revise control logic for completion of OBD-II Fuel System Readiness Monitor diagnosis.