Mercedes-Benz bulletin LI54.21-P-079255
What it saysComplaint Combustion engine does not start, MIL (Malfunction Indication Light) may light up in instrument cluster, only electric driving possible. NHTSA’s full summary ↓
Mercedes-Benz filed this with NHTSA as a service bulletin dated Jan 31, 2026, about the engine. It names 3 model years (2023–2025). 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 communicationComplaint Combustion engine does not start, MIL (Malfunction Indication Light) may light up in instrument cluster, only electric driving possible. Fault code P0E2F00 logged in control unit BMS N82/10. Cause Auxiliary consumer fuse in the HV battery has an open circuit, caused by a short circuit in the auxiliary consumer line. Remedy Requirement: Before carrying out test work, it must be ensured that the person performing the work has successfully completed the required qualification for work on the high-voltage system. Qualification according to WIS is required to replace the auxiliary consumer fuse including eLearning T3057D-US. TTB. Note: If the fault "P0E2F00 The electrical fuse B for the high voltage has a malfunction" is stored in the N82/10 BMS control unit, the HV protocol must also be checked to see whether the fuse for the auxiliary consumers is ok. Check: To determine the causing HV component in the auxiliary consumer line, please follow and process the guided troubleshooting of the fault "P0E2F00 The electrical fuse B for the high voltage has a malfunction" saved in the N82/10 BMS control unit.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| LI54.21-P-079255 | Service bulletin | Jan 31, 2026 | 11027903 | PDF, 38 KB |
What the document itself lists
Part the bulletin names
| Part number | Description | Qty | Find it |
|---|---|---|---|
| A7899800200 | Auxiliary consumer fuse parts | — | eBay Motors → |
Read by machine from the document NHTSA serves (2 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. Listings and prices on eBay Motors are the seller’s.
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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 themAlso filed against model years this site has no page for: 2023 Mercedes-Benz AMG S 63 E 4MATIC+; 2024 Mercedes-Benz AMG S 63 E 4MATIC+.
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 databaseOwners of the 1 model year this bulletin names have filed 2 complaints with NHTSA since 2015.
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 group26 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 |
|---|---|---|---|
| LI18.00-P-073137 | Service bulletin | Sep 26, 2026 | Complaint Sporadic warning message in instrument cluster "Engine oil pressure stop switch off vehicle" (or similar) is shown in red on vehi… |
| LI20.10-P-075374 | Service bulletin | Sep 17, 2026 | Complaint Red coolant warning in instrument cluster. Fault codes U019F00 or U019F87 current/stored in MRG1 control unit. Cause Various cause… |
| 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… |
| LI07.61-P-080241 | Service bulletin | Jun 11, 2026 | Complaint CEL ON with DTC P061197 "the control unit fuel injector has a malfunction output stage fault of control unit is restricted" active… |
| PSL-NCU Return Parts 6/05 | Other | Jun 5, 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… |
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 LI54.21-P-079255 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 LI54.21-P-079255 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 LI54.21-P-079255 cover?
The manufacturer filed it against 3 model years: 2025 Mercedes-Benz S-Class, 2023 Mercedes-Benz AMG S 63 E 4MATIC+, 2024 Mercedes-Benz AMG S 63 E 4MATIC+. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.