Mercedes-Benz bulletin LI27.19-P-080823
What it saysComplaint Customers may report one or more of the following: Transmission malfunction message Check engine light illuminated Shifts into N Concern disappears after ignition cycle When performing a quick test… NHTSA’s full summary ↓
Mercedes-Benz filed this with NHTSA as a service bulletin dated Aug 25, 2026, received Aug 5, 2026, about the power train — 2 documents under this number. It names 11 model years (2021–2023). 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 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 Customers may report one or more of the following: • Transmission malfunction message • Check engine light illuminated • Shifts into N • Concern disappears after ignition cycle When performing a quick test, the following fault code is stored in Y3/14 - Transmission control for 8-speed dual-clutch transmission (DKG): P056300 The on-board power supply voltage is too high. Cause An overvoltage condition is detected exclusively within the transmission control unit, storing fault P056300 once the measured voltage exceeds 16V. Remedy This LI applies if the freeze frame data for P056300 show a supply voltage between 15.75 to 16.50 volts, and no other control units report overvoltage. (figure 1) Long Term Resolution: Software resolutions are being rolled out for various models. Check validity and ensure your Xentry is updated with latest Addons before continuing: 1. Perform software update for Y3/14 - Transmission control for 8-speed dual-clutch transmission (DKG) - available software listed in Parts 2. Clear fault memory and perform final test drive Short Term Resolution: Please clear faults and perform an extended test drive. The vehicle may be released to the customer until software is available. If the customer complaint matches this LI and the software currently installed on the vehicle is not listed, please submit a TIPS case to the Powertrain inbox with the following information: - Initial Quick Test w/ Freeze Frame Data - DKG Control Unit Log - Latest EEPROM data - Screenshot of software availability
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| LI27.19-P-080823 | Service bulletin | Aug 25, 2026 | 11036514 | PDF, 40 KB |
| LI27.19-P-080823 | Service bulletin | Aug 4, 2026 | 11035713 | PDF, 71 KB |
What the document itself lists
Parts the bulletin names
| Part number | Description | Qty | Find it |
|---|---|---|---|
| A7249020705 | SW Available in Xentry for | — | eBay Motors → |
| A7249024001 | — | — | |
| A7249028400 | — | — | |
| A7249022205 | SW Available in Xentry for | — | eBay Motors → |
| A7249025901 | — | — | |
| A7249023705 | SW Available in Xentry for | — | eBay Motors → |
Read by machine from the document NHTSA serves (5 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.
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 11 model years this bulletin names have filed 137 complaints with NHTSA since 2015. 12 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.
The contact owns a 2021 Mercedes-Benz AMG GLB35. The contact stated that while reversing down the driveway at approximately 4 MPH, the contact turned the steering wheel to the left and the vehicle started losing motive power. The contact stated that the RPMs were extremely high and the vehicle almost stalled.
2021 Mercedes-Benz GLB-Class · Power Train · filed with NHTSA Jun 18, 2025 · ODI 11667631
The contact owns a 2023 Mercedes-Benz GLB250. The contact stated that while driving at an undisclosed speed, the vehicle lost motive power with the transmission warning light illuminated. The vehicle was towed to the dealer but was not diagnosed or repaired.
2023 Mercedes-Benz GLB-Class · Power Train · filed with NHTSA Apr 22, 2025 · ODI 11656155
this is a formal notification regarding my vehicle that I purchased at House Of Imports on February 27, 2021. Shortly after purchase I experienced several safety concerns about the vehicle.
2021 Mercedes-Benz A-Class · Power Train · filed with NHTSA Jan 28, 2026 · ODI 11714047
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… |
| 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… |
| LI27.19-P-080155 | Service bulletin | Dec 19, 2025 | Complaint Oil residue in connector of transmission control unit in dual-clutch transmission models 724.0 and 724.1. Cause As part of the pro… |
| 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-080823 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-080823 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-080823 cover?
The manufacturer filed it against 11 model years: 2022 Mercedes-Benz A-Class, 2021 Mercedes-Benz A-Class, 2023 Mercedes-Benz CLA-Class, 2022 Mercedes-Benz CLA-Class, 2021 Mercedes-Benz CLA-Class, 2023 Mercedes-Benz GLA-Class and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.