Mercedes-Benz bulletin LI77.20-P-073486
What it saysComplaint Water ingress at the sliding sunroof can lead to moisture in the interior. NHTSA’s full summary ↓
Mercedes-Benz filed this with NHTSA as a service bulletin dated Feb 24, 2026, received Feb 25, 2026, about the structure. It names 7 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 Water ingress at the sliding sunroof can lead to moisture in the interior. In some cases, the leakage may also be visible to the customer in the area of the overhead control panel. Cause The following causes can lead to water ingress in the area of the sliding sunroof and thus to moisture in the vehicle interior: 1. Incorrectly routed drain hoses: Water may accumulate in the rear area of the sliding sunroof frame (see picture #1). For example, the rear drain hoses may have been routed without sufficient slope, which consequently leads to the drains overflowing. Water can enter the vehicle interior through the headliner. 2. Sliding sunroof adjustment: An improper positioning of the tilting/sliding roof within the roof frame may, under certain circumstances, lead to increased water ingress through the seal between the sliding sunroof frame and the roof. However, one drop is permissible here. 3. Material degradation: Over time, the seal of the tilting/sliding roof may experience age-related changes in its elasticity, which could potentially affect its watertightness. Remedy Test procedure for suspected water ingress via the sliding sunroof: • In all three possible cases, the headliner must be removed. • First, the complaint must be reviewed. A rain test should be performed for this purpose. If water enters through the sliding/tilting roof, compare the amount of water entering with the reference video in the appendix. Please note that due to its design, the sliding sunroof is not completely watertight. (see Video 3) • If the amount of water does not correspond to the expected normal condition, the three potential causes should be checked, insofar as they apply to the specific case. (see Video 2) Re. cause 1: • Route the left rear and right rear drain hoses of the sliding sunroof frame from the upper clip-on point to the lower clip-on point. • This must be carried out for both fastening points at the C-pillar and D-pillar. Carry out this step on both the left and right side of the vehicle. • Then move the water drain hoses of the roof luggage rack mounts from the lower clip-on point to the upper clipon point (see Pictures 2 and 3, Video 1). • Reinstall the roof lining. Re. cause 2: • Adjust the sliding sunroof frame position relative to the roof (height) in accordance with WIS document AR77.20- P-1100XG. Re. cause 3: • Replace the seal on the tilting/sl
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| LI77.20-P-073486 | Service bulletin | Feb 24, 2026 | 11029024 | PDF, 528 KB |
What the document itself lists
Part the bulletin names
| Part number | Description | Qty | Find it |
|---|---|---|---|
| A2057800098 | — | — |
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. 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.
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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 32 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 structure
Source: same model, same component group8 other manufacturer communications filed against the Mercedes-Benz G-Class under the same component group (structure), newest first.
| 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… |
| LI88.80-P-080031 | Service bulletin | May 7, 2026 | Complaint Water ingress in the load compartment between the C and D pillars. Cause In the area of the rounding at the D-pillar, a leakage ma… |
| LI72.10-P-078836 | Service bulletin | Feb 25, 2026 | Complaint Wind noises from the area of the A-pillars on driver's and/or front passenger side. Cause Depending on the clamping force of the d… |
| LI98.00-P-078306 | Service bulletin | Feb 24, 2026 | Complaint After removing the transport protection from new vehicles, localized cloudy spots or streaks may appear on the paint surface. Thes… |
| LI72.10-P-079446 | Service bulletin | Aug 5, 2025 | Complaint: Customer complaint concerns wind/clattering noises upwards of 20mph in the area of the A-pillar, the outside mirror or at the fro… |
| LI88.60-P-079224 | Service bulletin | Apr 21, 2025 | Complaint The surface of the fuel filler flap may have visual reflections of light or waviness depending on the light and angle of viewing.… |
| LI98.00-P-078106 | Service bulletin | Sep 10, 2024 | Complaint Damage or discoloration to paint protection films on vehicle. Cause Chip protection films are a wear item that may need to be repl… |
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 LI77.20-P-073486 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 LI77.20-P-073486 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 LI77.20-P-073486 cover?
The manufacturer filed it against 7 model years: 2025 Mercedes-Benz G-Class, 2024 Mercedes-Benz G-Class, 2023 Mercedes-Benz G-Class, 2022 Mercedes-Benz G-Class, 2021 Mercedes-Benz G-Class, 2020 Mercedes-Benz G-Class and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.