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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
22-01-018H2022-03-08. Service bulletin. EQUIPMENT:ELECTRICAL; ENGINE AND ENGINE COOLING. Certain 2020-22MY Sonata (DN8a) and 2021-22MY Santa Fe (TMa) vehicles equipped with 2.5L engine may exhibit a MIL with DTC(s): • P2074: Mass Airflow Sensor Plausibility • P2074F0: Manifold Absolute Pressure/Mass Air Flow - Throttle Position Correlation at Lower Load • P2074F1: Manifold Absolute Pressure/Mass Air Flow - Throttle Position Correlation at Medium or High Load Secondary DTC(s) below may also be stored: • C136081: ESP Irreversible Error • C161308: CAN Signal Error EMS • C161386: CAN Signal Error EMS • C169381: Blind-Spot Collision Warning – CAN signal failure - ESC • C174181: ESC Not Available VSM (Check ESC) • C183586: CAN Message Failure ESC/IEB Vehicles diagnosed with DTC(s) may also experience reduced engine performance and limited power reduction mode. The ECM software revises the logic to accurately detect the amount of air the engine is receiving.
21-EM-012H2022-01-08. Service bulletin. ENGINE AND ENGINE COOLING:COOLING SYSTEM:HOSES/LINES/PIPING/FITTINGS. Certain vehicles listed below equipped with 2.5T turbo engines may have a misassembled check valve for the PCV (Positive Crankcase Ventilation) system, resulting in engine oil entering the intake and contaminating the air cleaner. This bulletin describes the procedure to clean the air intake system and replace the PCV check valve and air cleaner.
21-01-075H2022-01-08. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:ENGINE CONTROL MODULE (ECU/ECM). Certain 2020-22MY Sonata (DN8a), 2021-22MY Santa Fe (TMa), and 2022MY Tucson (NX4/NX4a) vehicles equipped with 2.5L engine may exhibit a MIL with DTC(s): • P2074: Mass Airflow Sensor Plausibility • P2074F0: Manifold Absolute Pressure/Mass Air Flow - Throttle Position Correlation at Lower Load • P2074F1: Manifold Absolute Pressure/Mass Air Flow - Throttle Position Correlation at Medium or High Load Secondary DTC(s) below may also be stored: • C136081: ESP Irreversible Error • C161308: CAN Signal Error EMS • C161386: CAN Signal Error EMS • C169381: Blind-Spot Collision Warning – CAN signal failure - ESC • C174181: ESC Not Available VSM (Check ESC) • C183586: CAN Message Failure ESC/IEB Vehicles diagnosed with DTC(s) may also experience reduced engine performance and limited power reduction mode. The ECM software revises the logic to accurately detect the amount of air the engine is receiving.
21-EM-010H-12021-12-09. Service bulletin. ENGINE AND ENGINE COOLING. Certain 2020-2021 Sonata (DN8a) vehicles with 1.6T engines may exhibit a check engine light in conjunction with a popping noise, abnormal smell from the engine compartment, rough running, or reduced power due to a misfire.
21-EM-011H2021-11-06. Service bulletin. ENGINE AND ENGINE COOLING. Certain Sonata N-Line vehicles may have an uneven appearance between LH and RH exhaust tips due to slightly misaligned rear mufflers. This bulletin describes the procedure to adjust and realign the rear mufflers to correct the appearance.
21-EM-010H2021-10-08. Service bulletin. ENGINE AND ENGINE COOLING. Certain 2020-2021 Sonata (DN8a) vehicles with 1.6T engines may exhibit a check engine light in conjunction with a popping noise, abnormal smell from the engine compartment, rough running, or reduced power due to a misfire.
21-01-051H2021-07-09. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin provides information related to an Electronic Control Module (ECM) software update which revises the OBD Air Fuel Ratio Imbalance (AFRI) monitor function frequency and cylinder imbalance diagnosis logic.
21-EM-004H2021-04-07. Service bulletin. EQUIPMENT; ENGINE AND ENGINE COOLING. This bulletin provides the service procedure for engine connecting rod bearing clearance testing. Perform the procedure outlined in this bulletin to fulfill the Bearing Clearance Test inspection requirements to determine next required steps.
21-EM-003H2021-04-06. Service bulletin. EQUIPMENT; ENGINE AND ENGINE COOLING. This bulletin provides the inspection procedure and repair guidelines for certain vehicles listed below.

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