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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: Engine 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-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-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.
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-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.
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-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.
23-01-093H2024-02-05. Service bulletin. ENGINE AND ENGINE COOLING. 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-EM-009H2023-12-22. Service bulletin. ENGINE AND ENGINE COOLING; POWER TRAIN. Certain 2020-2023MY Sonata Hybrid (DN8 HEV) vehicles may exhibit coolant leakage, engine overheating, and white smoke from the exhaust due to an internal leak at the Exhaust Heat Recovery System (EHRS) portion of the center muffler assembly. Follow the procedure outlined in this bulletin to repair this condition after confirming EHRS is leaking internally.
23-EM-005H2023-12-15. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin provides important checkpoint guidelines when performing engine oil and filter change services.
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-HC-002H2023-09-06. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:ENGINE CONTROL MODULE (ECU/ECM); POWER TRAIN. This bulletin provides information related to the Engine Control Module (ECM) software update and coolant replacement for 2020-2023MY Sonata Hybrid (DN8 HEV) vehicles to improve the coolant filling mode by discharging air bubbles.
23-EE-009H2023-09-06. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin provides warranty procedure for EGR Valve replacement related to DTC P0401 EGR Flow Insufficient on 2020 and 2021MY Sonata (DN8a) equipped with 2.5 GDI Vehicles.
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-FL-002H-12023-07-01. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin provides the diagnostic procedure for the GDI injector(s) in certain 21-23MY Sonata, 21-22MY Santa Fe, certain 22MY Santa Cruz, and certain 21-23MY Tucson equipped with 2.5L GDI engines with one or more misfire DTC(s) due to internally leaking GDI injector(s)
23-EE-005H2023-05-02. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin provides the procedure to repair poor pin tension at joint connector JE102 in certain Sonata (1.6 T-GDI engine) with one or more DTC.
23-EE-006H2023-05-02. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin provides the procedure to repair poor pin tension at joint connector JE202 in certain Sonata (2.5L GDI engine) with one or more DTC.
23-AT-003H2023-05-02. Service bulletin. ENGINE AND ENGINE COOLING. If you are servicing an 8-speed vehicle with a “Check Engine” light on and one or more of the DTC listed, follow the service procedure and replace the related solenoid and harness.
23-FL-002H2023-04-04. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin provides the diagnostic procedure for the GDI injector(s) in certain 21-23MY Sonata, 21-22MY Santa Fe, certain 22MY Santa Cruz, and certain MY21-23 Tucson equipped with 2.5L GDI engines with one or more misfire DTC(s) due to internally leaking GDI injector(s).
22-FL-002H2022-11-01. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin provides the diagnostic procedure for the GDI injector(s) in certain 21-22MY Sonata, Santa Fe, and certain 22MY Santa Cruz, and Tucson equipped with 2.5L GDI engines with one or more misfire DTC(s) due to internally leaking GDI injector(s).
22-AT-010H2022-08-24. Service bulletin. POWER TRAIN; ENGINE AND ENGINE COOLING. If you are servicing an applicable vehicle with a “Check Engine” light on and one or more of the DTC listed below, follow the Service Procedure and replace the valve body internal harness and the input/output speed sensor.
22-EM-010H2022-08-05. Service bulletin. ENGINE AND ENGINE COOLING. 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-AT-008H2022-07-09. Service bulletin. ENGINE AND ENGINE COOLING. If you are servicing an applicable vehicle with a “Check Engine” light on and one or more of the DTC listed below, follow the Service Procedure and replace the related solenoid and harness.
Certain vehicles2022-04-08. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; ENGINE. If you are servicing an applicable vehicle with a “Check Engine” light on and one or more of the DTC listed below, follow the Service Procedure and replace the harness with an integrated oil temperature sensor.

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