Mercedes-Benz bulletin LI27.00-P-078372
What it saysComplaint Reverse unavailable message, Possible Limp home and Check Engine Light. NHTSA’s full summary ↓
Mercedes-Benz filed this with NHTSA as a service bulletin dated Sep 25, 2024, received Sep 14, 2024, about the power train — 2 documents under this number. It names 3 model years (2024). 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 Reverse unavailable message, Possible Limp home and Check Engine Light. Resolved after Key-Cycle Cause Fault code P092100 on control unit variant TCM8FDCT_PT4 with the fault environment data starting with the HEX blocks: 01 01 00 08 02 00 40 08 02. Additionally fault code P07FF00 can be present Remedy Software has been released and available for update through Xentry.
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| LI27.00-P-078372 | Service bulletin | Sep 25, 2024 | 11008066 | PDF, 141 KB |
| LI27.00-P-078372 | Service bulletin | Sep 11, 2024 | 11007793 | 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 3 model years this bulletin names have filed 10 complaints with NHTSA since 2015. 5 of them name Electrical System, 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 engine light comes on constantly. The 1st incident happened 05/2024. I have reported this to the dealership and was told it was ok to drive. Then it kept happening, on 11/05/24 I took the vehicle in for repair. It was returned 11/08/24 and ilthe engine light turned on again.
2024 Mercedes-Benz GLA-Class · Electrical System · filed with NHTSA Dec 11, 2024 · ODI 11630121
Rear Camera malfunction The flap of the reversing camera opens and closes by itself during forward travel, making a loud thumb noise every time the car slows down to an intersection. No camera image is displayed in the head unit.
2024 Mercedes-Benz GLB-Class · Electrical System · filed with NHTSA Jul 28, 2025 · ODI 11676547
This vehicle has suffered from persistent, substantial, and uncorrected defects, including but not limited to failures in the 48V mild-hybrid electrical system, lithium-ion battery system, DC/DC converter and coolant system.
2024 Mercedes-Benz CLA-Class · Electrical System · filed with NHTSA Apr 27, 2026 · ODI 11734113
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… |
| 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… |
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 LI27.00-P-078372 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 LI27.00-P-078372 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 LI27.00-P-078372 cover?
The manufacturer filed it against 3 model years: 2024 Mercedes-Benz CLA-Class, 2024 Mercedes-Benz GLA-Class, 2024 Mercedes-Benz GLB-Class. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.