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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 bulletin are shown. Show all

Bulletins, newest first
26-EM-016H TSB2026-10-14. Service bulletin. ENGINE. 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. ENGINE. 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.
26-AT-005H TSB2026-06-16. Service bulletin. POWER TRAIN. 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. Some 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.
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.
26-AT-001H TSB2026-03-11. Service bulletin. POWER TRAIN. Some Santa Cruz (NXT), Santa Fe (TMA, MX5A), and Sonata (DN8A) models may require replacement of the 8-speed wet dual clutch transmission (8WDCT) when the vehicle sets one of the high pressure electric oil pump (HP EOP) DTCs listed below. This bulletin provides instructions to replace the 8WDCT.
26-AD-001H TSB2026-03-07. Service bulletin. FORWARD COLLISION AVOIDANCE: WARNINGS; LANE DEPARTURE: ASSIST; EXTERIOR LIGHTING; FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL; LANE DEPARTURE: WARNING. Some 2019MY and newer vehicles equipped with a front view camera may illuminate certain warning lights and trigger DTC C272246 fault code for the front camera. In the following cases, the front camera auto-calibration range may be exceeded while driving: • If the front camera is not properly installed and is completely or partially detached. • In case of excessive changes affecting the vehicle's balance (e.g., loading excessively heavy cargo in a specific location of the vehicle, or significant under-inflation of the tires). • Specific road conditions affecting the vehicle's balance (e.g., excessive road crown) This TSB provides instructions on how to service the vehicle when the front camera related warning light(s) are triggered due to system out of calibration (DTC_C272246).
26-EM-003H TSB2026-02-10. Service bulletin. ENGINE. Some Sonata (DN8, DN8A) vehicles may have DTCs P218100, P2181F0, and/or P2181F1 (Cooling System Performance) set in the Engine Control Module, resulting in an illuminated Check Engine warning lamp. Follow the procedure in this TSB to replace the Integrated Thermal Management (ITM) module and update both the Engine Control Module (ECM) and Transmission Control Module (TCM) if applicable. Follow the flowchart in this TSB to update the appropriate modules.
26-FL-001H TSB2026-01-13. Service bulletin. FUEL/PROPULSION SYSTEM. Some vehicles equipped with a 2.5L GDI Theta III engine (non-Turbo) may exhibit one or more misfire DTCs due to the GDI fuel injectors leaking internally. This may be caused by internal filter breakage in the injector. Follow the procedure in this TSB to replace all 4 injectors on affected vehicles, using the kit in the Parts Information section.
25-EM-007H TSB2026-01-06. Service bulletin. ENGINE. Some Elantra (CN7, CN7A), Kona (OS, SX2), and Sonata Hybrid (DN8 HEV) vehicles equipped with 2.0L engines may illuminate a warning lamp for DTC P218100 (Cooling System Performance) related to the Integrated Thermal-Management Module (ITM). Follow the service procedure in this bulletin to install a spring onto the thermostat within the ITM, in order to prevent premature opening, and perform an ECU software update on affected vehicles.
25-BD-012H TSB2025-11-12. Service bulletin. EXTERIOR LIGHTING. This bulletin provides information regarding condensation related to the accumulated moisture in the headlamp, rear combination lamp, daytime running lamp (DRL), or fog lamp. This TSB illustrates the various causes of condensation inside the lamp assembly. Lamp assembly replacement is NOT necessary in most cases. This condition can be eliminated by turning on the lamps with the engine running for several minutes or during normal driving operation.
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-AT-001H TSB2025-06-03. Service bulletin. POWER TRAIN. Certain Santa Fe (TMA) and Sonata (DN8/DN8A) vehicles equipped with 8-speed dual clutch transmissions (8DCT) may exhibit one of the DTCs listed below, related to the high pressure electric oil pump (HP EOP). Follow the procedures in this TSB to update the Transmission Control Unit (TCU) to the latest sensorless logic on affected vehicles, and then perform air bleeding and transmission learning.
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-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.
25-01-010H DN2025-02-17. Service bulletin. FUEL/PROPULSION 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 25-01-010H (or latest version) to perform the update the Battery management System (BMS) software.
25-FL-001H2025-01-13. Service bulletin. FUEL/PROPULSION SYSTEM. Some vehicles equipped with a 2.5L GDI Theta III engine (non-Turbo) may exhibit one or more misfire DTCs due to the GDI injectors leaking internally. This may be caused by internal filter breakage in the injector. Follow the procedure in this TSB to replace all 4 injectors on affected vehicles, using the kit in the Parts Information section.
24-AT-001H-12024-12-21. Service bulletin. POWER TRAIN. This bulletin provides the procedure for updating the automatic transmission TCU (Transmission Control Unit) software to improve shift quality, judder and hesitation when accelerating.
24-EM-001H2024-08-07. Service bulletin. ENGINE. Certain 20-22MY Sonata (DN8a), 21-23MY Santa Fe (TMa), and 22-23MY Tucson (NX4a) vehicles may experience a warning lamp illumination for a diagnostic trouble code P2181 that is related to the Integrated Thermal Management Module (ITM). Follow the service procedure outlined in this bulletin to replace the ITM.
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.
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-AT-002H2024-04-16. Service bulletin. POWER TRAIN. This TSB provides a procedure to diagnose and replace, if necessary, an automatic transmission with Incorrect Ratio DTC (transmission clutch slip in gear above limit) listed on Page 2.
24-FL-002H2024-03-05. Service bulletin. POWER TRAIN; ENGINE AND ENGINE COOLING:ENGINE:ENGINE CONTROL MODULE (ECU/ECM); ENGINE AND ENGINE COOLING. This bulletin provides the procedure to update the Engine Control Module (ECM) and/or the Transmission Control Module (TCM) for 2020-2023MY Sonata (DN8/DN8a) vehicles to improve operation of the Idle Stop and Go (ISG) system. Under certain circumstances the vehicle may not restart after the ISG system has engaged and requires a manual restart due to the lack of intake manifold pressure recovery.
24-AT-001H2024-03-05. Service bulletin. POWER TRAIN. This bulletin provides the procedure for updating the automatic transmission TCU and ECU software (Santa Fe ONLY) to improve shift quality, judder with ISG enabled and hesitation when accelerating.
24-BD-001H2024-03-05. Service bulletin. VISIBILITY; VISIBILITY/WIPER. This bulletin contains information about the proper removal of the windshield wiper blade protective cover on all models. If the protective cover is not removed correctly, there is a possibility of the rubber insert and rail spring becoming partially separated on the inner side of the wiper blade, which could lead to poor wiping performance and/or possible scratching of the windshield glass. Follow the procedure in this bulletin to properly remove the windshield wiper blade protective cover on all new wiper blades.

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