Hyundai service campaign SERVICE CAMPAIGN 9B4
What it saysCertain Elantra hybrid (CN7 HEV), Sonata hybrid (DN8 HEV), and Tucson hybrid (NX4 HEV) vehicles may exhibit a warning light due to DTC Code P1BB20 (12V Lithium Battery Cell Voltage High). NHTSA’s full summary ↓
Hyundai filed this with NHTSA as a service campaign dated Jul 9, 2024, received Aug 7, 2024, about the electrical system — 1 document under this number: 24-01-054H. It names 6 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 communicationWhat 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.
Certain Elantra hybrid (CN7 HEV), Sonata hybrid (DN8 HEV), and Tucson hybrid (NX4 HEV) vehicles may exhibit a warning light due to DTC Code P1BB20 (12V Lithium Battery Cell Voltage High). Follow the procedure in TSB 24-01-054H (or latest version) to perform the update the Battery management System (BMS) software.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 24-01-054H | Service campaign | Jul 9, 2024 | 11006056 | PDF, 302 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 6 model years this bulletin names have filed 993 complaints with NHTSA since 2015. 245 of them name 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.
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
My car will power off randomly, or will seem as though there is no power. I have to revert back to the manual key to enter the vehicle and hit the 12vlt reset to power it back on. This happened at least 3 times. Once while operating the vehicle, and twice while the vehicle was left parked.
2021 Hyundai Sonata · Electrical System · filed with NHTSA Jun 4, 2024 · ODI 11592346
My hyundai elantra 2022 hybrid abruptly told me to pull over after driving on the highway for 30 minutes. The Hybrid Warning System light came up on dash and told me to pull over. After pulling over the car lost power and had to be jumped with the 12V battery reset button.
2022 Hyundai Elantra · Electrical System · filed with NHTSA Sep 24, 2024 · ODI 11616178
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 electrical system
Source: same model, same component group42 other manufacturer communications filed against these Hyundai models under the same component group (electrical system), newest first. The eight newest are listed; the rest are on the Hyundai list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| 26-GI-003H | Service bulletin | Oct 27, 2026 | This bulletin provides information related to the navigation and head unit software changes introduced in the 2026 2nd Navigation Map and So… |
| LA29 / LA30 | Warranty extension | Jul 14, 2026 | Certain 2024-2026MY Sonata (DN8) and 2024-2026MY Sonata Hybrid (DN8 HEV) vehicles may exhibit intermittent battery discharge condition due t… |
| LA30 | Warranty extension | Jul 13, 2026 | Certain Sonata Hybrid (DN8 HEV) vehicles may exhibit intermittent battery discharge conditions due to the air conditioning controller not fu… |
| LA29 | Warranty extension | Jul 13, 2026 | Certain Sonata (DN8) vehicles may exhibit intermittent battery discharge condition due to the air conditioning controller not fully powering… |
| 26-GI-002H | Service bulletin | May 27, 2026 | This bulletin provides information related to the navigation and head unit software changes introduced in the 2026 1st Navigation Map and So… |
| 9C0 | Service campaign | Apr 8, 2026 | Some vehicles may exhibit a loss of connectivity or interruptions in the middle of using Bluelink functions. This may be due to an occasiona… |
| 26-EM-009H | Service bulletin | Mar 24, 2026 | Some Sonata (DN8) and Tucson (NX4/NX4A/NX4M) vehicles equipped with the 2.5L Theta III GDI engine may display a warning lamp and store Diagn… |
| P33 | Other | Dec 19, 2025 | In response to this trend, we engineered a software upgrade that addresses the social media theft method and made it available to owners of… |
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 SERVICE CAMPAIGN 9B4 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 SERVICE CAMPAIGN 9B4 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 SERVICE CAMPAIGN 9B4 cover?
The manufacturer filed it against 6 model years: 2023 Hyundai Elantra, 2022 Hyundai Elantra, 2021 Hyundai Elantra, 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 15 Dec 2020 – 13 Feb 2023; built 29 Jan 2020 – 8 Mar 2023; built 20 Jan 2021 – 18 Dec 2023 — the build date is on the certification label in the driver’s door jamb.