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Service bulletins for the 2021 Hyundai Sonata

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.

109 on file from NHTSA, as of 2026-10-19.

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Only bulletins with type: Service campaign are shown. Show all

Bulletins, newest first
25-01-010H-1 9B4 OL2025-08-22. Service campaign. ELECTRICAL SYSTEM. Certain Hyundai vehicles may exhibit a warning light with Diagnostic Trouble Code (“DTC”) P1BB20 due to a battery over voltage condition.
25-01-010H-1 DN2025-07-22. Service campaign. ELECTRICAL SYSTEM. Certain Elantra Hybrid (CN7 HEV), Sonata Hybrid (DN8 HEV), and Tucson Hybrid (NX4 HEV) vehicles may exhibit a warning light due to DTC Code P1BB20 (12V Lithium Battery Cell Voltage High). The California Air Resources Board has determined that these vehicles may be releasing air pollutants which exceed Federal and California standards.
25-01-010H-1 TSB2025-07-22. Service campaign. ELECTRICAL SYSTEM. This bulletin provides the procedure to update the software for the Battery Management System (BMS) on certain Elantra Hybrid (CN7 HEV), Sonata Hybrid (DN8 HEV), and Tucson Hybrid (NX4 HEV) vehicles that may exhibit a warning light with DTC P1BB200 and enter Limp Mode.
25-01-024H-1 TSB2025-05-27. Service campaign. ELECTRICAL SYSTEM. Some vehicles may exhibit a loss of connectivity or interruptions in the middle of using Bluelink Service functions. This may be due to an irregular disconnection on Verizon’s communication network. Follow the procedure in this TSB to reestablish the connection via the AVN pinhole reset method.
25-01-024H EM2025-04-18. Service campaign. ELECTRICAL SYSTEM. Some vehicles may exhibit a loss of connectivity or interruptions in the middle of using Bluelink Service functions. This may be due to an irregular disconnection on Verizon's communication network. If you are experiencing issues with remote commands, or other Bluelink services, please see the instructions below to reestablish the connection via the AVN pinhole reset method.
25-01-024H TSB2025-03-25. Service campaign. ELECTRICAL SYSTEM. Some vehicles may exhibit a loss of connectivity or interruptions in the middle of using Bluelink Service functions. This may be due to an irregular disconnection on Verizon’s communication network. Follow the procedure in this TSB to reestablish the connection via the AVN pinhole reset method.
25-01-010H TSB2025-02-17. Service campaign. FUEL/PROPULSION SYSTEM. This bulletin provides the procedure to update the software for the Battery Management System (BMS) on certain Elantra Hybrid (CN7 HEV), Sonata Hybrid (DN8 HEV), and Tucson Hybrid (NX4 HEV) vehicles that may exhibit a warning light with DTC P1BB20.
25-01-001H TSB2025-01-06. Service campaign. FUEL/PROPULSION SYSTEM. Certain 2021-2023MY Sonata (DN8) and 2020-2022MY Sonata (DN8A) vehicles may have DTC P0451 stored in the ECU. Follow this bulletin to inspect the check valve, fuel pump cover and fuel tank, and update the ECU. If necessary, replace the check valve and/or fuel tank based on inspection results. The ECU Upgrade contains a revised DTC P14EE00 which supersedes P0451.
25-01-001H DBP2025-01-06. Service campaign. FUEL/PROPULSION SYSTEM. Certain 2021-2023MY Sonata (DN8) and 2020-2022MY Sonata (DN8A) vehicles may have Diagnostic Trouble Code (DTC) P0451 (also known as DTC P14EE00) stored in the Electronic Control Unit (ECU). The California Air Resources Board has determined that these vehicles may be releasing air pollutants which exceed Federal and California standards.
9B1 OL2024-12-13. Service campaign. ELECTRICAL SYSTEM. The subject vehicles may have Diagnostic Trouble Code (DTC) P0451 stored in the ECU, which could cause the Check Engine Lamp to come on.
24-01-020H DBP2024-12-03. Service campaign. FUEL/PROPULSION SYSTEM. Certain 2021-2023MY Sonata (DN8) and 2020-2022MY Sonata (DN8A) vehicles may have Diagnostic Trouble Code (DTC) P0451 stored in the Electronic Control Unit (ECU). The California Air Resources Board has determined that these vehicles may be releasing air pollutants which exceed Federal and California standards.
24-01-020H TSB2024-12-03. Service campaign. FUEL/PROPULSION SYSTEM. Certain 2021-2023MY Sonata (DN8) and 2020-2022MY Sonata (DN8A) vehicles may have DTC P0451 stored in the ECU. Follow this bulletin to inspect the check valve, fuel pump cover and fuel tank, and update the ECU. If necessary, replace the check valve and/or fuel tank based on inspection results.
24-01-054H2024-08-07. Service campaign. ELECTRICAL SYSTEM. Certain Elantra hybrid (CN7 HEV), Sonata hybrid (DN8 HEV), and Tucson hybrid (NX4 HEV) vehicles may exhibit a warning light due to DTC Code P1BB20 (12V Lithium Battery Cell Voltage High). Follow the procedure in TSB 24-01-054H (or latest version) to perform the update the Battery management System (BMS) software.

The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.