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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 component: Electrical system are shown. Show all

Bulletins, newest first
26-EE-003H TSB2026-04-21. Service bulletin. ENGINE; ELECTRICAL SYSTEM. Some vehicles may exhibit difficulty starting in cold weather. This bulletin provides the procedure to perform an inspection on the starter magnetic switch for potential freezing and, if necessary, replace the starter magnetic switch (solenoid) assembly.
25-BE-020H TSB2025-10-03. Service bulletin. ELECTRICAL SYSTEM. This bulletin provides information related to the changes introduced in the 2025 1st Navigation Map and Software Update. The changes may vary depending on vehicle type, model, and navigation system as described in this TSB.
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-BE-002H TSB2025-06-03. Service bulletin. ELECTRICAL SYSTEM. This bulletin provides information related to the changes introduced in the 2024 2nd Navigation Map and Software Update. The changes may vary depending on vehicle type, model, and navigation system. Refer to the 2024 2nd Navigation Map and Software Update Improvements section in this TSB for a list of specific changes. The software can be downloaded via Navigation Updater (NAU) and updated by USB. The NAU website is https://update.hyundai.com/US/EN/navigationUpdate. For certain models equipped with a relevant Bluelink package, the software may be downloaded and applied via OTA update.
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-EE-002H2025-05-02. Service bulletin. ENGINE; ELECTRICAL SYSTEM. Certain Sonata (DN8) and Sonata (DN8A) vehicles may experience issues with the air conditioning due to damaged wiring in the engine room junction box. This bulletin provides instructions to replace the multi-fuse, reroute the damaged wiring using the blower wiring kit, and replace the fuse label.
25-EE-002H TSB2025-04-30. Service bulletin. ELECTRICAL SYSTEM. Certain Sonata (DN8) and Sonata (DN8A) vehicles may experience issues with the air conditioning due to damaged wiring in the engine room junction box. This bulletin provides instructions to replace the multi-fuse, reroute the damaged wiring using the blower wiring kit, and replace the fuse label.
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.
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-BE-001H-12024-08-07. Service bulletin. ELECTRICAL SYSTEM. Some vehicles equipped with the AVN 5th Gen Wide system may exhibit a condition where the radio app crashes frequently when entering radio mode and/or displays a message that reads “Uneven Road Ahead, Drive carefully” on the cluster along with a warning sound. Follow the procedure outlined in this bulletin to update the AVN software to resolve this condition.
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.
SERVICE CAMPAIGN 9B42024-08-07. Service bulletin. 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 P1BB20.
24-BE-001H2024-02-05. Service bulletin. ELECTRICAL SYSTEM. Some vehicles equipped with the AVN 5th Gen Wide system may exhibit a condition where the radio app crashes frequently when entering radio mode and/or displays a message that reads “Uneven Road Ahead, Drive carefully” on the cluster along with a warning sound. Follow the procedure outlined in this bulletin to update the AVN software to resolve this condition.
23-01-093H2023-12-22. Service bulletin. ELECTRICAL SYSTEM; POWER TRAIN. This bulletin provides the procedure to update the Hybrid Control Unit (HCU) and Dual Automatic Temperature Control (DATC) software to help improve coolant flow to the Exhaust Heat Recovery System (EHRS).
23-EE-010H2023-10-02. Service bulletin. ELECTRICAL SYSTEM; ENGINE AND ENGINE COOLING. This bulletin is issued to provide the extended battery diagnosis procedure using GDS-M. This battery diagnosis function displays the various battery-related faults such as: • Internal short circuit • Battery deterioration • Malfunction of electronic parts • Insufficient battery charge • Normal battery • Charging defect Battery diagnosis uses the battery sensor history saved for the last 30 days and ICU diagnostic communication to track battery state of charge (SOC) and current parasitic draw history.
23-AT-009H2023-08-02. Service bulletin. POWER TRAIN; POWER TRAIN:AUTOMATIC TRANSMISSION:GEAR POSITION INDICATION (PRNDL); ENGINE AND ENGINE COOLING:ENGINE:ENGINE CONTROL MODULE (ECU/ECM); POWER TRAIN:AUTOMATIC TRANSMISSION; ELECTRICAL SYSTEM:WIRING:POSITION/LIMIT SENSOR/SWITCH. If you are servicing an 8-speed DCT front-wheel-drive vehicle with the DTC or symptoms listed below, refer to the Service Procedure to diagnose the condition. • DIAGNOSTIC TROUBLE CODES: ➢ P070500 - Transmission range sensor circuit malfunction ➢ P070512 - Transmission range sensor circuit malfunction ➢ P070514 - Transmission range sensor circuit malfunction ➢ P07051C - Transmission range sensor circuit malfunction ➢ P070600 - Transmission range sensor circuit range/performance ➢ P070661 - Transmission range sensor circuit range/performance ➢ P070696 - Transmission range sensor circuit range/performance • SYMPTOMS: ➢ Malfunction Indicator Light (MIL) illuminated ➢ 5th gear fail-safe ➢ Intermittently won’t shift into D or R ➢ Intermittently won’t shift out of P ➢ Intermittent ly no engine crank in “P” or “
23-BE-007H2023-08-02. Service bulletin. EQUIPMENT:ELECTRICAL:INFOTAINMENT:SOFTWARE; ELECTRICAL SYSTEM. This Service Information bulletin provides information on how to update the Apple Carplay software from Hyundai’s Navigation Updates page. The current version of Google Maps has 10 times the data transmission compared to the previous version. As a countermeasure, an update with a frame skip logic has been added to resolve the data congestion with Google Maps.
21-BE-002H2021-03-05. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; ELECTRICAL SYSTEM. This bulletin describes the procedure to update the radio software to help reduce the disconnection occurrences.
21-01-007H2021-02-06. Service bulletin. ELECTRICAL SYSTEM. When using Wireless CarPlay, the system may intermittently auto disconnect. When Wireless CarPlay is disconnected, a pop up message “Phone Not Responding. Please reconnect it and try again” will appear on the radio screen. This bulletin describes the procedure to update the radio software to help reduce the disconnection occurrences.
21-GI-001H2021-02-06. Service bulletin. ELECTRICAL SYSTEM. This bulletin provides information on the Launch Quality Monitoring Process (LQMP) for the 2021MY Hyundai Sonata N Line. After a new vehicle launch, Hyundai uses the LQMP to monitor all customer and dealer activities at a minimum of 100 days. The Sonata N Line LQMP helps improve model vehicle quality, and allows Hyundai to proactively respond to the Voice of the Customer (VOC).
20-BE-014H2021-01-09. Service bulletin. ELECTRICAL SYSTEM. When using Wireless CarPlay, the system may intermittently auto disconnect. When Wireless CarPlay is disconnected, a pop up message “Phone Not Responding. Please reconnect it and try again” will appear on the radio screen.

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