Hyundai service campaign 9B1
What it saysCertain 2021-2023MY Sonata (DN8) and 2020-2022MY Sonata (DN8A) vehicles may have Diagnostic Trouble Code (DTC) P0451 stored in the Electronic Control Unit (ECU). NHTSA’s full summary ↓
Hyundai filed this with NHTSA as a service campaign dated Dec 10, 2024, received Dec 3, 2024, about the fuel/propulsion system — 3 documents under this number: 9B1 OL, 24-01-020H DBP, 24-01-020H TSB. It names 4 model years (2020–2023). A service campaign is not a safety recall — there is no NHTSA campaign number and no federal requirement — but it is usually work the manufacturer pays for on the vehicles it names; the dealer checks the VIN against the manufacturer’s list.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationCertain 2021-2023MY Sonata (DN8) and 2020-2022MY Sonata (DN8A) vehicles may have Diagnostic Trouble Code (DTC) P0451 stored in the Electronic Control Unit (ECU). The California Air Resources Board has determined that these vehicles may be releasing air pollutants which exceed Federal and California standards.
Trouble codes it names: P0451
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 9B1 OL | Service campaign | Dec 10, 2024 | 11011830 | PDF, 230 KB |
| 24-01-020H DBP | Service campaign | Nov 14, 2024 | 11010975 | PDF, 364 KB |
| 24-01-020H TSB | Service campaign | Nov 14, 2024 | 11010974 | PDF, 1,983 KB |
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.
Model years it names
Source: as the manufacturer filed themA 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 databaseOwners of the 4 model years this bulletin names have filed 605 complaints with NHTSA since 2015. 310 of them name Fuel/Propulsion System, Electrical System — 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.
On the 2020 Hyundai Sonata, the 12 owners who gave an odometer reading for Fuel/Propulsion System reported it at a median of 80,000 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.
Over the last 3 months at least a dozen times the 12v auxiliary battery is completely dead after parking the car outdoors for an hour or so. This poses a safety issue, especially at night because you cannot easily access the car. You have to fumble around trying to get the key hole cover off in order to use the key supplied in the fob.
2020 Hyundai Sonata · Electrical System · filed with NHTSA Oct 1, 2024 · ODI 11617570
Fuel injector failed. The vehicle stall and accelerate poorly due to misfires. It is leaching gasoline into the oil which can result in total engine failure. Dealership verified the injector was bad. There was a warning light at one time after refueling, presumed it was my fuel cap, tightened it, and the light went away
2022 Hyundai Sonata · Fuel/Propulsion System · filed with NHTSA Sep 5, 2025 · ODI 11685272
Had been traveling for approximately 2.5 hours in a winter storm, pushed on brake to slow down and park and the car started to chug. Turned car off and then back on again. Car would not start and had to be towed to nearest Hyundai dealership. There were no warning signs at all, car just suddenly quit.
2023 Hyundai Sonata · Fuel/Propulsion System · filed with NHTSA Feb 13, 2024 · ODI 11571570
In depth: 2020 Hyundai Sonata fuel system 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 fuel/propulsion system
Source: same model, same component group4 other manufacturer communications filed against the Hyundai Sonata under the same component group (fuel/propulsion system), newest first.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| 26-FL-002H | Service bulletin | Jun 3, 2026 | Some Sonata Hybrid (DN8 HEV) vehicles may display a Check Engine light and store one or more of the DTCs listed below due to an abnormal air… |
| 26-FL-001H | Service bulletin | Jan 7, 2026 | 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 leaki… |
| 25-FL-001H | Service bulletin | Jan 9, 2025 | 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 in… |
| 25-01-001H | Service campaign | Jan 3, 2025 | Certain 2021-2023MY Sonata (DN8) and 2020-2022MY Sonata (DN8A) vehicles may have DTC P0451 stored in the ECU. Follow this bulletin to inspec… |
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.
Common questions
Source: NHTSA, 49 CFR 579.5Is Hyundai 9B1 a recall?
No. A service campaign 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 9B1 repair free?
A service campaign is usually paid by the manufacturer on the vehicles it names, within the terms and time limit the document sets; the dealer checks the VIN against the manufacturer’s list.
Which vehicles does 9B1 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.