Mercedes-Benz bulletin LI54.30-P-078529
What it saysComplaint During cold starting, a tortoise symbol may be displayed in the event of reduced engine output. NHTSA’s full summary ↓
Mercedes-Benz filed this with NHTSA as a service bulletin dated Aug 10, 2026, received Oct 25, 2024, about the electrical system — 2 documents under this number. It names 6 model years (2022–2026). 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 During cold starting, a tortoise symbol may be displayed in the event of reduced engine output. (see attachment) For "non-hybrid vehicles", the thermostat symbol must be displayed. (see attachment) Cause SCN Coding of the N133/1 IC-Instrument-Cluster Remedy Perform N133/1 IC-Instrument-Cluster manual SCN coding.
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| LI54.30-P-078529 | Service bulletin | Aug 10, 2026 | 11036105 | PDF, 55 KB |
| LI54.30-P-078529 | Service bulletin | Oct 23, 2024 | 11009125 | PDF, 55 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 themAlso filed against model years this site has no page for: 2024 Mercedes-Benz AMG C63 S E.
A 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 5 model years this bulletin names have filed 75 complaints with NHTSA since 2015. 20 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.
I acquired a Mercedes-Benz C300 from Mercedes-Benz of White Plains at on the last day of XXX Within 2 days of the car sitting in my driveway, I took it out for a drive; the electronic systems failed while I was driving on the highway. The speedometer and odometer went dark, and the turn signals stopped working.
2026 Mercedes-Benz C-Class · Electrical System · filed with NHTSA Aug 26, 2026 · ODI 11759811
The electronic system, specifically the battery, failed and it is available for inspection upon request. The persistent battery drain caused the vehicle to become inoperable multiple times, including an incident where I was stranded 200 miles from home with my wife and dog, posing significant safety risks.
2022 Mercedes-Benz C-Class · Electrical System · filed with NHTSA Jun 3, 2024 · ODI 11592228
CEL followed by no crank / no start. Codes u3017 and u0168. Software flashed and no crank / no start returned. SAM & EIS modules replaced and no crank/no start returned with new codes. U103F00 + P143400 + P051300. Now Mercedes is directing the replacement of the ethernet harness between the SAM and EIS.
2026 Mercedes-Benz C-Class · Electrical System · filed with NHTSA Aug 30, 2026 · ODI 11760695
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 electrical system
Source: same model, same component group123 other manufacturer communications filed against these Mercedes-Benz models under the same component group (electrical system), newest first. The eight newest are listed; the rest are on the Mercedes-Benz list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| LI54.30-P-080963 | Service bulletin | Sep 17, 2026 | Complaint Issue after OTA Update IC Odometer Reading blank("_ _ _ _") IC Maintanence data unavailable Cause OTA Update E61.0 Remedy In the I… |
| LI82.60-P-080383 | Service bulletin | Sep 15, 2026 | Complaint Radio station cover art does not refresh when switching stations. The UI continues to show the old station’s artwork instead of up… |
| LI54.71-P-079104 | Service bulletin | Sep 11, 2026 | Complaint Traffic sign symbol for "Traffic Sign Assist" is blinking in instrument cluster without obvious cause usually with one of the foll… |
| LI82.60-P-079747 | Service bulletin | Sep 4, 2026 | Complaint The Apple Music app is no longer available in the head unit apps menu after updating the software of the… |
| LI82.85-P-079088 | Service bulletin | Aug 14, 2026 | Complaint The following most common complaints may be observed: • Brief connectivity interruptions when using Apple CarPlay over Wi-Fi • Aud… |
| LI54.65-P-080132 | Service bulletin | Aug 12, 2026 | Complaint 1. General Diagnostic Tips 2. One or More PARK Sensor Activations 3. Red Ring Around Vehicle 4. "Active Parking and Parking Assist… |
| LI54.10-P-080880 | Service bulletin | Aug 12, 2026 | Complaint Customer Complaint: - AC charging is not possible. - The departure time, charging pause, location-based charging or target SOC lim… |
| LI54.10-P-080881 | Service bulletin | Aug 11, 2026 | Complaint AC and DC charging are not possible. The white LED on the charging inlet completely goes OFF after plugging in the charging cable.… |
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 LI54.30-P-078529 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 LI54.30-P-078529 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 LI54.30-P-078529 cover?
The manufacturer filed it against 6 model years: 2026 Mercedes-Benz C-Class, 2025 Mercedes-Benz C-Class, 2024 Mercedes-Benz C-Class, 2023 Mercedes-Benz C-Class, 2022 Mercedes-Benz C-Class, 2024 Mercedes-Benz AMG C63 S E. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.