Mercedes-Benz bulletin LI15.40-P-077947
What it saysComplaint Combustion engine can no longer be started, only electric driving possible Cause High-voltage belt-driven starter-alternator has a failure Remedy Requirement: Prior to the implementation of the test work, it… NHTSA’s full summary ↓
Mercedes-Benz filed this with NHTSA as a service bulletin dated Aug 9, 2025, received Aug 28, 2024, about the engine — 4 documents under this number. It names 26 model years (2019–2025). 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 can no longer be started, only electric driving possible Cause High-voltage belt-driven starter-alternator has a failure Remedy Requirement: Prior to the implementation of the test work, it must be ensured that the person carrying out this work has successfully completed the qualification "T1716F Diagnosis at high voltage level 4" and the vehicle-specific training. Note: In order to check whether the high-voltage belt-driven starter-alternator has a failure, please carry out the test below. 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 be checked to see whether the fuse for the auxiliary consumers has a failure. In this case, the high-voltage battery must be replaced after the short circuit has been eliminated. (See attachment) The faulty component high-voltage belt-driven starter-alternator must always be sent back via the existing return delivery process for analysis. Check: Please disconnect the high-voltage plug at the high-voltage belt-driven starter-alternator and connect test adapter 000 589 94 63 00. Measure resistance HV+ to HV-. If the final measurement result is between 0–1 ohm, the high-voltage belt-driven starter-alternator with the short circuit must be replaced. If either one of or both the fault codes P0C0B16 and P0C0B17 are saved in the high-voltage belt-driven starter-alternator control unit G2/3, please replace the high-voltage belt-driven starter-alternator, since no short circuit can be measured here and this therefore concerns a hardware failure. Please check the serial number on the silver adhesive label below the SW number on the front of the high-voltage belt-driven starter-alternator. Example: 2314300044 (the first 10 digits, see attachment) Important note: If the number is small or greater than 2329100027, a TIPS case must be created. In this instance, please attach the following documents to the TIPS case: • Quick test • High-voltage event log • Picture of the silver adhesive label on the front of the high-voltage belt-driven starter-alternator (serial number) • Attach the measurement results with pictures approved tools and equipment. It informs service technicians about conditions that could occur in certain vehicles and provides information that could assist in proper vehicle diagnosis, service, or re
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| LI15.40-P-077947 | Service bulletin | Aug 9, 2025 | 11021892 | PDF, 15,042 KB |
| LI15.40-P-077947 | Service bulletin | Oct 16, 2024 | 11008977 | PDF, 15,042 KB |
| LI15.40-P-077947 | Service bulletin | Sep 18, 2024 | 11008035 | PDF, 15,016 KB |
| LI15.40-P-077947 | Service bulletin | Aug 23, 2024 | 11006636 | PDF, 15,040 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 themAlso filed against model years this site has no page for: 2024 Mercedes-Benz AMG C63 S E; 2020 Mercedes-Benz AMG GT43; 2024 Mercedes-Benz AMG GT53E; 2022 Mercedes-Benz AMG GT63; 2022 Mercedes-Benz AMG GT63 S; 2024 Mercedes-Benz AMG S 63 E 4MATIC+; 2024 Mercedes-Benz AMG SL53E.
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 19 model years this bulletin names have filed 331 complaints with NHTSA since 2015. 171 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.
On Sunday, XXX at approximately 5:30 PM, I entered the parking lot of a Staples store at , in my 2025 Mercedes Benz AMG GLC 43 SUV. It was daylight and the weather was clear. There was no wind and the temperature was in the low 80s. I drove down a parking aisle and slowed down to make a right turn into an open parking space.
2025 Mercedes-Benz GLC-Class · Electrical System · filed with NHTSA Sep 21, 2026 · ODI 11765946
The contact owns a 2025 Mercedes-Benz GLC 300. The contact stated that while her husband was driving at 5 to 10 MPH attempting to park the vehilce lunged forward traveling 20 feet and crashed into the house. The air bags deployed. No warning lights were illuminated , There was no injuries or fire. A police report was filed.
2025 Mercedes-Benz GLC-Class · Engine · filed with NHTSA Jun 4, 2026 · ODI 11741988
Vehicle: 2022 Mercedes-Benz S580 The vehicle is experiencing a severe and violent drivetrain "jolt" or "push" during gear transitions, specifically when shifting from 5th to 6th gear at cruising speeds. On multiple occasions, the jolt was so forceful that passengers believed the vehicle had been rear-ended by another car.
2022 Mercedes-Benz S-Class · Engine · filed with NHTSA Apr 19, 2026 · ODI 11732269
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 group65 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… |
| 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… |
| NCU - 2026010004 | Service campaign | Jul 27, 2026 | • Always use the latest XENTRY Diagnosis software release with all available add-ons. • Make sure to follow the operation steps exactly as d… |
| 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… |
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 LI15.40-P-077947 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 LI15.40-P-077947 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 LI15.40-P-077947 cover?
The manufacturer filed it against 26 model years: 2025 Mercedes-Benz AMG GT, 2024 Mercedes-Benz AMG GT, 2023 Mercedes-Benz AMG GT, 2022 Mercedes-Benz AMG GT, 2021 Mercedes-Benz AMG GT, 2020 Mercedes-Benz AMG GT and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.