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Manufacturer communication · Service bulletin

Hyundai bulletin 24-FL-002H

What it saysThis 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)… NHTSA’s full summary ↓

Hyundai filed this with NHTSA as a service bulletin dated Feb 29, 2024, received Mar 5, 2024, about the engine. It names 4 model years (2020–2023). A service bulletin is not a safety recall: it is the manufacturer telling its dealers how to diagnose or repair a condition, and whether the work is paid for depends on the warranty in force. Quoting the number at a service desk can save a diagnosis.

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What the bulletin says

Source: NHTSA's summary of the manufacturer's communication
Built 3 Jun 2021 – 23 Oct 2023 “Produced 6/3/2021 – 10/23/2023”
Built 23 Oct 2019 – 14 Feb 2022 “Produced 10/23/2019 – 2/14/2022”

What it applies to, as the document itself states it — the build window in the manufacturer’s own words, read by machine from the PDF NHTSA serves. The build date is on the certification label in the driver’s door jamb; the dealer settles a borderline vehicle by its VIN.

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.

Kind Service bulletin Manufacturer date Feb 29, 2024 Received by NHTSA Mar 5, 2024 Components Engine, Power Train

Document filed under this number

DocumentKindDatedNHTSA idAt NHTSA
24-FL-002HService bulletinFeb 29, 202410251294PDF, 289 KB

What the document itself lists

The manufacturer titles it “ECU/TCU SOFTWARE UPDATE FOR ISG LOGIC IMPROVEMENT”.

Parts the bulletin names

Part numberDescriptionQtyFind it
39110-2S040——
39110-2S279——
39110-2S042Take a screenshot of the ECU update—eBay Motors →
39102-2SDB0——
39104-2SDF0——
39100-2SDH0——
39100-2SDK0——
39110-2S038Manual Mode Password: Event # 1076—eBay Motors →
39100-2SDM0Manual Mode Password: Event # 1077—eBay Motors →

Labour operation and the time the manufacturer allows

OperationDescriptionTime
39110FH4 ECU + TCU Software Update0.6 hrs

Read by machine from the document NHTSA serves (6 pages), read Sep 30, 2026. A part number is shown only where it matches Hyundai’s own catalogue shape, an operation only with its code and time, and a description only where the reader got it whole; anything it could not settle is left out, and the PDF is the record. Times are the manufacturer’s warranty allowances, not a quote. Listings and prices on eBay Motors are the seller’s.

Affiliate disclosure: some links on this page are affiliate links. If you request a quote or buy through them we may earn a commission at no extra cost to you. Nothing on this page changes because of it.

The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5. One communication is usually filed as several documents — the bulletin, a dealer notice, an owner letter — and the number on any of them finds this page. A PDF link is shown only once NHTSA’s own server has been seen to serve that document; the rest are checked over the following nights. Quote the number at a service desk; it is what the dealer’s system is keyed on.

Doing the repair yourself, or pricing it before the shop does? Search the part by fitment on eBay Motors — the listing and the price are the seller’s.

Find the engine control module (ecu/ecm) for the 2023 Sonata →

Affiliate disclosure: some links on this page are affiliate links. If you request a quote or buy through them we may earn a commission at no extra cost to you. Nothing on this page changes because of it.

Model years it names

Source: as the manufacturer filed them

A vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.

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What owners reported

Source: NHTSA complaint database

Owners of the 4 model years this bulletin names have filed 605 complaints with NHTSA since 2015. 262 of them name Engine, Power Train — the same broad component group this bulletin is filed under. NHTSA groups complaints coarsely, so that means the same area of the vehicle, not necessarily the same fault.

Occasionally there is a serious delay when trying to accelerate. Car tends to jerk/buck when accelerating, usually in the lower gears. I have no idea if this is a transmission issue or a fuel injection issue, but my dealership has not been able to detect an issue and keeps telling me everything is normal when it clearly isn't.

2020 Hyundai Sonata · Power Train · filed with NHTSA Jan 4, 2021 · ODI 11386446

Initially had loss of cabin heat. Later, vehicle randomly overheated. Repair shop replaced EGR due to finding confidant buildup of water/coolant mix. Within one week, problem returned. Dealer notified me that while replacing another part they found a TSB for coolant leakage into exhaust that was consistent with my issue.

2021 Hyundai Sonata · Engine · filed with NHTSA Feb 13, 2024 · ODI 11571605

The contact owns a 2022 Hyundai Sonata. The contact stated while driving 30 MPH, there was a delay while shifting into another gear. The contact stated that the chassis warning light was illuminated. The contact also stated that the front driver’s side door failed to latch and close properly.

2022 Hyundai Sonata · Power Train · filed with NHTSA Jul 24, 2023 · ODI 11534058

In depth: 2021 Hyundai Sonata engine problems →

A complaint is one owner’s account, not a defect finding, and a bulletin is not a recall. Nothing here says this bulletin was issued because of these complaints, or that the repair it describes fixed them. Complaint files on this site begin in 2015.

More bulletins about the engine

Source: same model, same component group

18 other manufacturer communications filed against the Hyundai Sonata under the same component group (engine), newest first. The eight newest are listed; the rest are on the Hyundai list.

NumberKindDatedNHTSA’s summary
26-EM-016HService bulletinOct 8, 2026Some vehicles equipped with internal combustion engines may exhibit higher-than-expected engine oil consumption. This bulletin outlines the…
26-EM-015HService bulletinOct 7, 2026Certain vehicles equipped with internal combustion engines may exhibit higher-than-expected engine oil consumption. This bulletin provides t…
9C2Service campaignMay 21, 2026Certain 2019 – 2020 model year Santa Fe, 2017 – 2018 model year Santa Fe Sport, 2015 – 2019 model year Sonata, and 2018 – 2021 model year Tu…
26-EE-003HService bulletinApr 18, 2026Some vehicles may exhibit difficulty starting in cold weather. This bulletin provides the procedure to perform an inspection on the starter…
T6GWarranty extensionMar 26, 2026This TSB references the Op codes to use for claim submission and the Parts required based on the vehicle’s inspection results from TSB 22-01…
T6G TXXMWarranty extensionMar 26, 2026This TSB references the Op codes to use for claim submission and the Parts required based on the vehicle’s inspection results from TSB 22-01…
26-EM-003HService bulletinFeb 5, 2026Some Sonata (DN8, DN8A) vehicles may have DTCs P218100, P2181F0, and/or P2181F1 (Cooling System Performance) set in the Engine Control Modul…
25-EM-007HService bulletinDec 18, 2025Some Elantra (CN7, CN7A), Kona (OS, SX2), and Sonata Hybrid (DN8 HEV) vehicles equipped with 2.0L engines may illuminate a warning lamp for…

Quote the number at the service desk. It is what the dealer’s system is keyed on.

Every manufacturer communication NHTSA holds for Hyundai, by the number printed on the letter.

Photo: Christian Buehner / Unsplash

Common questions

Source: NHTSA, 49 CFR 579.5

Is Hyundai 24-FL-002H a recall?

No. A service bulletin is a manufacturer communication filed with NHTSA under 49 CFR 579.5; a safety recall carries an NHTSA campaign number (two digits, a letter, six digits) and a federal duty to repair for free. Check the vehicle’s recalls by VIN at nhtsa.gov/recalls, or on its page here.

Is the 24-FL-002H repair free?

Not automatically. A service bulletin describes how to diagnose or repair a condition; who pays depends on the warranty in force, any extension, and the dealer. Quoting the number can save a diagnosis either way. Every Hyundai warranty extension on file lists the ones Hyundai has filed.

Which vehicles does 24-FL-002H cover?

The manufacturer filed it against 4 model years: 2023 Hyundai Sonata, 2022 Hyundai Sonata, 2021 Hyundai Sonata, 2020 Hyundai Sonata. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone. The document itself sets the build window: built 3 Jun 2021 – 23 Oct 2023; built 23 Oct 2019 – 14 Feb 2022 — the build date is on the certification label in the driver’s door jamb.