Mercedes-Benz bulletin NCU - 2025040001
What it saysMercedes-Benz AG, the manufacturer of Mercedes-Benz vehicles, has determined that on certain subject vehicles, the engine control software might not meet current specifications. NHTSA’s full summary ↓
Mercedes-Benz filed this with NHTSA as an emissions communication dated Feb 7, 2026, about the engine. It names 3 model years (2023). An emissions communication 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 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, the manufacturer of Mercedes-Benz vehicles, has determined that on certain subject vehicles, the engine control software might not meet current specifications. As a result, the diagnosis routine for monitoring the air-fuel ratio might not be activated as intended and a malfunction in the oxygen sensor could be erroneously detected causing the “check engine” Malfunction Indicator Lamp (‘MIL’) to illuminate. MBUSA will conduct a voluntary emissions recall. An authorized Mercedes-Benz dealer will update the engine control unit software.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| NCU - 2025040001 | Emissions | Feb 7, 2026 | 11028648 | PDF, 505 KB |
What the document itself lists
Parts the bulletin names
| Part number | Description | Qty |
|---|---|---|
| A 000 584 54 13 | — | — |
| A 000 584 42 14 | Proof of Correction Certificate (CA Dealers Only) | — |
Read by machine from the document NHTSA serves (4 pages), read Sep 30, 2026. A part number is shown only where it matches Mercedes-Benz’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.
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 3 model years this bulletin names have filed 33 complaints with NHTSA since 2015. 11 of them name Electrical System, Engine — 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.
My mom and I were in her car brand new Mercedes adaptive cruise was on the car started to act up with all the warning lights again, which shut all safety systems down air back seatbelts, adaptive cruise, Tronics and the engine wall between 18 wheeler and the freeway wall slammed the vehicle into the freeway hall causing about $5000 worth…
2023 Mercedes-Benz SL-Class · Electrical System · filed with NHTSA Jan 21, 2025 · ODI 11637467
Was driving the vehicle on the street when it turned off without notice. I pressed the gas pedal and noticed the vehicle did not accelerate. The cluster showed “see manual” , a red exclamation ❗️and all the warning lights were illuminated.
2023 Mercedes-Benz G-Class · Engine · filed with NHTSA Jul 9, 2024 · ODI 11600650
My vehicle developed a coolant warning during normal road use. I had not experienced any known collision, crash, or unusual impact. I brought the vehicle to an authorized Mercedes-Benz dealer for inspection.
2023 Mercedes-Benz C-Class · Engine · filed with NHTSA Sep 24, 2026 · ODI 11766731
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 group56 other manufacturer communications filed against these Mercedes-Benz models under the same component group (engine), newest first. The eight newest are listed; the rest are on the Mercedes-Benz list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| PSL-NCU Return Parts 8/14 | Other | Aug 15, 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… |
| LI01.20-P-080884 | Service bulletin | Aug 12, 2026 | Complaint Oil leaks found on M176 or M177 engines diagnosed to be from the cylinder head cover area Cause Unknown (under investigation) Reme… |
| LI07.10-P-080384 | Service bulletin | Aug 7, 2026 | Complaint Customer reports Check Engine Light with possible loss of power concern. The Following DTC's are present • P210185 - The throttle… |
| LI20.10-P-072886 | Service bulletin | Jul 24, 2026 | Complaint Check Engine Light ON with DTC P012800 "The Coolant Temperature is Below the Specified Temperature" active and/or stored in the ME… |
| Emissions - 2024100016 | Emissions | Jul 24, 2026 | Mercedes-Benz AG (“MBAG”), the manufacturer of Mercedes-Benz, has determined that on certain MY 2019-2021 C-Class, G-Class, GLC, GT, S-Class… |
| NCU - 2026050002 | Service campaign | May 15, 2026 | Mercedes-Benz AG (“MBAG”), the manufacturer of Mercedes-Benz vehicles, has determined that on certain Model Year (“MY”) 2026 G-Class… |
| LI07.70-P-078293 | Service bulletin | Apr 9, 2026 | Complaint Customer states CEL ON with no drivability complaints Cause The following DTC is active and/or stored in the ME (N3/10) due to sig… |
| LI01.30-P-072328 | Service bulletin | Mar 27, 2026 | Complaint -Check engine light illuminated. -Engine runs rough. -Poor shifting or jerking when accelerating. -Fault codes stored related to m… |
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 - 2025040001 a recall?
No. A emissions communication 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 - 2025040001 repair free?
A emissions communication 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 NCU - 2025040001 cover?
The manufacturer filed it against 3 model years: 2023 Mercedes-Benz C-Class, 2023 Mercedes-Benz G-Class, 2023 Mercedes-Benz SL-Class. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.