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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 control module are shown. Show all

Bulletins, newest first
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-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-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 “
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.

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