Mercedes-Benz bulletin LI27.19-P-080155
What it saysComplaint Oil residue in connector of transmission control unit in dual-clutch transmission models 724.0 and 724.1. NHTSA’s full summary ↓
Mercedes-Benz filed this with NHTSA as a service bulletin dated Dec 19, 2025, received Dec 24, 2025, about the power train. It names 33 model years (2016–2026). 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 communicationWhat it applies to, as NHTSA’s summary states it — build dates and equipment as the manufacturer filed them. The dealer checks the VIN and the build date on the door jamb; a vehicle outside the window is not covered by this bulletin.
Complaint Oil residue in connector of transmission control unit in dual-clutch transmission models 724.0 and 724.1. Cause As part of the production process, the electrohydraulic controller units are subjected to a function test in an oil bath. Any oil residue remaining in the connector area can be regarded as production process-related. Since the oil used is a non-conducting, non-corrosive medium, the oil residue does not cause any technical impairment and does not result in any consequential damage. Remedy No action or replacement of parts is required! If necessary, clean the connector using compressed air only. Do not use any cleaning agents such as brake cleaner, as this could potentially cause consequential damage!
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| LI27.19-P-080155 | Service bulletin | Dec 19, 2025 | 11026832 | PDF, 10,453 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 33 model years this bulletin names have filed 665 complaints with NHTSA since 2015. 53 of them name Power Train — 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.
Extended warrenty information mercedez benz has issued warrenty to that applie to condistions as listed above (exhaust valve, cyliner head ) back 08/04/2023 the car has in mercedez benz and have failed to pick on the extended warrrenty repairs and we now find out this cased more damage to the engine and needs to replace camshat and…
2020 Mercedes-Benz GLB-Class · Power Train · filed with NHTSA Jun 15, 2026 · ODI 11744345
My 2018 Mercedes-Benz CLA250 4MATIC is experiencing a knocking noise from the rear differential at low speeds. The issue poses potential driving hazards, including possible loss of control and increased wear on drivetrain components. The noise may indicate a failing differential, which could suddenly fail while driving.
2018 Mercedes-Benz CLA-Class · Power Train · filed with NHTSA Sep 5, 2024 · ODI 11612753
Check engine light received a diagnosis from Mercedes dealership that the crankcase ventilator line is malfunctioning and it’s a very common issue with this model. The transmission stalls during driving, the gears do not jump properly and the car cannot reverse, extremely dangerous at intersections and on the highway.
2017 Mercedes-Benz GLA-Class · Power Train · filed with NHTSA Jan 6, 2025 · ODI 11634299
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 power train
Source: same model, same component group11 other manufacturer communications filed against these Mercedes-Benz models under the same component group (power train), newest first. The eight newest are listed; the rest are on the Mercedes-Benz list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| LI 27.10-P-080851 | Service bulletin | Aug 29, 2026 | Complaint Intermittent shift feel or thud/clunk noise perceived, such as a brief jerk or transmission reaction during certain driving situat… |
| LI27.19-P-080823 | Service bulletin | Aug 25, 2026 | Complaint Customers may report one or more of the following: • Transmission malfunction message • Check engine light illuminated • Shifts in… |
| PSL-NCU Return Parts 8/21 | Other | Aug 21, 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… |
| LI35.30-P-058566 | Service bulletin | Jul 14, 2026 | Complaint Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end). The noise is heard once… |
| LI35.31-P-074854 | Service bulletin | Jan 23, 2026 | Complaint Noises from the rear axle differential, particularly when cornering slowly Cause Small quantity of water entering into oil of mult… |
| LI33.30-P-056665 | Service bulletin | Nov 15, 2025 | Complaint Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end). The clunk is heard once… |
| LI35.31-P-077429 | Service bulletin | Oct 29, 2025 | Instrument cluster message "4MATIC inoperative". The following fault code may be present in all-wheel drive control unit N15/17: P147354 - E… |
| LI27.19-P-072588 | Service bulletin | Sep 17, 2025 | Complaint Transmission control unit Y3/8n4 (fully integrated transmission control unit (VGS)) not listed in quick test and/or no communicati… |
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 LI27.19-P-080155 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 LI27.19-P-080155 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 LI27.19-P-080155 cover?
The manufacturer filed it against 33 model years: 2022 Mercedes-Benz A-Class, 2021 Mercedes-Benz A-Class, 2020 Mercedes-Benz A-Class, 2019 Mercedes-Benz A-Class, 2026 Mercedes-Benz CLA-Class, 2025 Mercedes-Benz CLA-Class and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.