Mercedes-Benz bulletin LI91.29-P-079178
What it saysComplaint After opening the driver's door, the seat can no longer be moved using the Memory button. NHTSA’s full summary ↓
Mercedes-Benz filed this with NHTSA as a service bulletin dated Apr 8, 2026, received Apr 22, 2025, about the seats — 2 documents under this number. It names 4 model years (2023–2026). 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 After opening the driver's door, the seat can no longer be moved using the Memory button. Adjustment via the seat adjustment switch is still possible. Example: Driver 1 parks the vehicle in the evening and the seat position is right to the front with Memory button 1. Driver 2 opens the driver's door and presses Memory button 2, as seat position 1 is too far forward to get in. The seat does not move to the saved rear seat position 2. Once the ignition is turned "on", the function is available again. Cause The cause is currently being investigated. Remedy Please create a TIPS case with a quick test and video of the complaint. Send the cases to the Body/Chassis/Entertainment inbox.
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| LI91.29-P-079178 | Service bulletin | Apr 8, 2026 | 11031205 | PDF, 35 KB |
| LI91.29-P-079178 | Service bulletin | Apr 21, 2025 | 11017128 | PDF, 35 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 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 4 model years this bulletin names have filed 155 complaints with NHTSA since 2015. 72 of them name Electrical System — 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
This vehicle has now had three episodes where warning lights came on for no apparent reason. There have been two episodes of "Check Engine Light" coming on, the first with less than 1000 miles on the vehicle. It was driven to the dealer and they checked finding no problems and said not to worry about it.
2023 Mercedes-Benz GLC-Class · Electrical System · filed with NHTSA Jan 3, 2024 · ODI 11563288
The MBUX/center display has malfunctioned repeatedly. The enter display suddenly went to completely black on the three separate occasions, and on one additional occasion three times. MBUX system froze and became completely unresponsive. These are four separate incidents, not a one-time occurrence.
2026 Mercedes-Benz GLC-Class · Electrical System · filed with NHTSA Oct 1, 2026 · ODI 11768366
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 seats
Source: same model, same component group6 other manufacturer communications filed against the Mercedes-Benz GLC-Class under the same component group (seats), newest first.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| LI91.10-P-076097 | Service bulletin | May 19, 2026 | Complaint Play/noise at height adjuster or in seat guide rail on front seats Cause Tolerances and variations in the manufacturing process Re… |
| LI91.29-P-080554 | Service bulletin | May 15, 2026 | Complaint One or more seat functions are restricted or inoperative. This may include: • Seat memory • Automatic seat adjustment • Easy Entry… |
| LI91.10-P-078305 | Service bulletin | Mar 26, 2026 | Complaint The "easy entry and exit feature" function deactivates itself after a brief period. (see attachment) Cause The cause is currently… |
| LI91.10-P-079346 | Service bulletin | Jul 31, 2025 | Complaint The customer complains about squeaking/creaking noises on uneven roadways, on bends or when moving in their seat. Cause Noise in t… |
| LI91.18-P-077075 | Service bulletin | Dec 4, 2023 | Crease formation on genuine leather seat covers in vehicles with low mileage ⢠Objects left on the seats for extended periods of time… |
| LI91.10-P-076798 | Service bulletin | Aug 18, 2023 | Noise at front seats between seat-back lining and function carrier. Noise is caused by friction of the two component parts. Remove the… |
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 LI91.29-P-079178 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 LI91.29-P-079178 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 LI91.29-P-079178 cover?
The manufacturer filed it against 4 model years: 2026 Mercedes-Benz GLC-Class, 2025 Mercedes-Benz GLC-Class, 2024 Mercedes-Benz GLC-Class, 2023 Mercedes-Benz GLC-Class. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.