Mercedes-Benz bulletin LI77.21-P-074971
What it saysComplaint Sliding sunroof panel of panoramic sliding sunroof reversed (temporarily, once, multiple times) during closing process without entrapment event. NHTSA’s full summary ↓
Mercedes-Benz filed this with NHTSA as a service bulletin dated Oct 3, 2024, received Jul 5, 2022, about the structure — 4 documents under this number. It names 8 model years (2022–2023). 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 communicationComplaint Sliding sunroof panel of panoramic sliding sunroof reversed (temporarily, once, multiple times) during closing process without entrapment event. Cause It is not possible to save the relearning process for force progression after each actuation. A, e.g. mechanical sluggishness caused by aging cannot be compensated for here. Remedy Perform commissioning of panoramic roof control unit (PSD, A98, TSSR223). Reference to escalation closing during reversing processes (also described in Operator’s Manual), if vehicle in customer possession (see Video_1): If the panoramic roof blocks up when closing and then opens again slightly (reversing process): Immediately after automatic reversing, wipe forwards on the control panel of the overhead control panel and hold until the panoramic roof is closed. The panoramic roof is closed with greater closing force. If the panoramic roof blocks up again and then opens again slightly (reversing process): repeat previous step. The panoramic roof is closed again with greater closing force.
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| LI77.21-P-074971 | Service bulletin | Oct 3, 2024 | 11008875 | PDF, 39 KB |
| LI77.21-P-074971 | Service bulletin | Jul 25, 2023 | 10240164 | PDF, 41 KB |
| LI77.21-P-074971 | Service bulletin | Jan 4, 2023 | 10231033 | PDF, 37 KB |
| LI77.21-P-074971 | Service bulletin | Jun 16, 2022 | 10215000 | PDF, 36 KB |
What the document itself lists
Part the bulletin names
| Part number | Description | Qty | Find it |
|---|---|---|---|
| A2149028501 | — | — |
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.
Doing the repair yourself, or pricing it before the shop does? Search the part by fitment on eBay Motors — the listing and the price are the seller’s.
Find the sun/moon roof assembly for the 2023 C-Class →Affiliate disclosure: some links on this page are affiliate links. If you request a quote or buy through them we may earn a commission at no extra cost to you. Nothing on this page changes because of it.
Model years it names
Source: as the manufacturer filed themAlso filed against model years this site has no page for: 2022 Mercedes-Benz AMG C63 S; 2023 Mercedes-Benz Redundant EQE 350 4MATIC; 2023 Mercedes-Benz Redundant EQS 450.
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 5 model years this bulletin names have filed 202 complaints with NHTSA since 2015. 6 of them name Structure — 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.
The center console display (MBUX) on this 2023 EQS 450 4MATIC fails while the vehicle is in use. There is no warning lamp, chime or message first. Sometimes it flickers on and off; other times it goes fully blank and stays blank, unresponsive to touch. Owner video shows the display working and then completely blank 0.4 seconds later.
2023 Mercedes-Benz EQS · Visibility/Wiper · filed with NHTSA Sep 5, 2026 · ODI 11762332
While driving at 60mph my panoramic sunroof completely shattered. Nothing at all hit the sunroof to cause it to shatter. If my sunshade cover had not been on, the glass would have fallen on me while operating my vehicle. This is not only dangerous but unacceptable. It was also a distraction that could have caused an accident.
2023 Mercedes-Benz C-Class · Structure · filed with NHTSA May 23, 2025 · ODI 11662742
When going into Reverse the passenger side mirror angles down to see curbs. When putting back into Drive it should be going back up to normal angle, but 20% of the time it does not go back up. If you're driving in the dark you may not know it's reverted back up and get into a car accident.
2023 Mercedes-Benz C-Class · Visibility/Wiper · filed with NHTSA Nov 15, 2025 · ODI 11699593
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 structure
Source: same model, same component group23 other manufacturer communications filed against these Mercedes-Benz models under the same component group (structure), newest first. The eight newest are listed; the rest are on the Mercedes-Benz list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| LI82.62-P-078631 | Service bulletin | Sep 14, 2026 | Complaint Clanking noise from the area of the speakers in the doors. Cause Under analysis. Remedy To narrow down the cause, first of all rem… |
| LI72.20-P-075746 | Service bulletin | Aug 24, 2026 | Complaint Tailgate opens unintentionally. Cause Accidental or unnoticed activation of the button to open the tailgate on the vehicle key. EX… |
| LI72.00-P-080885 | Service bulletin | Aug 14, 2026 | Complaint The Dark Chrome finish on the retractable door handle appears discolored, stained, or faded. The discoloration is typically visibl… |
| PSL-NCU Return Parts 7/3 | Other | Jul 3, 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… |
| LI77.30-P-070145 | Service bulletin | Apr 28, 2026 | Complaint Damaged cords/tensioning cables at the soft top interior trim with the following characteristics: - Cord/tensioning cable torn - C… |
| LI80.20-P-078308 | Service bulletin | Mar 23, 2026 | Complaint Depending on the identified problem (items 1-4), please implement the corresponding Remedy below (items 1-4): 1. KeylessGo sensor… |
| NCU - 2025120008 | Service campaign | Jan 10, 2026 | Additional loose or jammed fasteners may be present in the area between the front axle torsion bar and integral carrier, which might result… |
| LI72.12-P-076175 | Service bulletin | Sep 15, 2025 | Complaint Seal secured to B-pillar trim on rear doors cracked in upper area, see picture 1. Cause Production deviation at supplier of B-pill… |
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 LI77.21-P-074971 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 LI77.21-P-074971 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 LI77.21-P-074971 cover?
The manufacturer filed it against 8 model years: 2023 Mercedes-Benz C-Class, 2022 Mercedes-Benz C-Class, 2023 Mercedes-Benz EQE, 2023 Mercedes-Benz EQS, 2022 Mercedes-Benz EQS, 2022 Mercedes-Benz AMG C63 S and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.