Mercedes-Benz bulletin NCU-2023040017
What it saysMercedes-Benz AG (“MBAG”), the manufacturer of Mercedes-Benz vehicles, has determined that on certain MY 2022-2023 C-Class, EQS and S-Class (206, 297 and 223 platform) vehicles, the driving assistance system control… NHTSA’s full summary ↓
Mercedes-Benz filed this with NHTSA as a service bulletin dated May 19, 2023, received Jun 5, 2023, about the service brakes. It names 7 model years (2021–2023). 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 communicationPicked out of NHTSA’s summary below, word for word. The document itself is the record, and the dealer checks the VIN.
Mercedes-Benz AG (“MBAG”), the manufacturer of Mercedes-Benz vehicles, has determined that on certain MY 2022-2023 C-Class, EQS and S-Class (206, 297 and 223 platform) vehicles, the driving assistance system control unit software does not meet current specifications. In the presence of uniquely shaped civil superstructures that parallel the roadway at a height of~26-33 feet (e.g. large overhanging bridge abutments, etc.), the vehicle may initiate brake applications during operation. In such cases, the driver remains in control of the vehicle and can override the system at any time. What We’re Doing An authorized Mercedes-Benz dealer will update the driving assistance system control unit software.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| NCU-2023040017 | Service bulletin | May 19, 2023 | 10237265 | PDF, 732 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 7 model years this bulletin names have filed 258 complaints with NHTSA since 2015. 235 of them name Forward Collision Avoidance, Electrical System, Service Brakes — 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.
I am filing a safety complaint regarding my 2023 Mercedes-Benz AMG C43 4MATIC. The vehicle has approximately 23,000 miles. On multiple occasions, the vehicle has abruptly and violently applied the brakes and/or come to a near stop while I was driving on highways and side roads, even though there was nothing in front of me that should…
2023 Mercedes-Benz C-Class · Service Brakes · filed with NHTSA May 5, 2026 · ODI 11735812
I am formally reporting a serious and potentially life-threatening safety issue with this vehicle and requesting an immediate investigation and recall consideration. On 09/21/2026 at approximately 5:05 PM, I was driving along with my wife on westbound Tennyson Road in Hayward during heavy traffic, the vehicle suddenly stopped without…
2022 Mercedes-Benz EQS · Forward Collision Avoidance · filed with NHTSA Oct 2, 2026 · ODI 11768567
Every Mercedes Benz manufactured in 2021 has a defective hood lens which prevents the adaptive driver assistance system from working properly. You can have it on and it will work intermittently which can easily cause a major crash. Mercedes Benz says the part is not available in USA or Germany. Every Mercedes is affected.
2021 Mercedes-Benz S-Class · Forward Collision Avoidance · filed with NHTSA Jun 1, 2024 · ODI 11591956
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 service brakes
Source: same model, same component group5 other manufacturer communications filed against these Mercedes-Benz models under the same component group (service brakes), newest first.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| LI42.10-P-078779 | Service bulletin | Sep 22, 2026 | Complaint Repeat workshop visit for vehicle vibration while braking from 60MPH. NOTE: Although the symptom is similar to a tire or wheel vib… |
| LI42.10-P-063502 | Service bulletin | Sep 1, 2026 | Complaint Noises/ squealing from the service brake in various driving situations and ambient conditions. Cause Frictional vibrations Remedy… |
| PSL-NCU Return Parts 5/29 | Other | May 30, 2026 | Dear Mercedes-Benz USA Dealers, The part numbers listed in the chart below should no longer be installed, and any existing stock must be ret… |
| EW - Pressure Trans M157 | Warranty extension | Mar 13, 2026 | In our continuing efforts to ensure the proper performance of Mercedes-Benz products and to enhance the satisfaction of our customers, Merce… |
| LI42.10-P-079904 | Service bulletin | Oct 20, 2025 | Complaint At low speeds and light brake pressure, brakes will make a groaning or honking noise. Cause Frictional vibrations with very light… |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Mercedes-Benz, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is Mercedes-Benz NCU-2023040017 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 NCU-2023040017 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 Mercedes-Benz warranty extension on file lists the ones Mercedes-Benz has filed.
Which vehicles does NCU-2023040017 cover?
The manufacturer filed it against 7 model years: 2023 Mercedes-Benz C-Class, 2022 Mercedes-Benz C-Class, 2023 Mercedes-Benz EQS, 2022 Mercedes-Benz EQS, 2023 Mercedes-Benz S-Class, 2022 Mercedes-Benz S-Class and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.