Mercedes-Benz bulletin LI82.70-P-079903
What it saysComplaint Noise interference when using the hands-free system (phone call). NHTSA’s full summary ↓
Mercedes-Benz filed this with NHTSA as a service bulletin dated Mar 7, 2026, received Oct 21, 2025, about the electrical system — 4 documents under this number. It names 6 model years (2020–2025). 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.
Get the next Mercedes-Benz G-Class bulletin by email Weekly, only when something new is filed. Nothing else; one-click unsubscribe.
What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationComplaint Noise interference when using the hands-free system (phone call). Cause The noise is caused by electromagnetic interference (EMC fault) affecting the microphone lines and thus impacting voice quality. The severity of these faults may vary depending on the vehicle. Remedy To avoid EMC-related interference noise, the SOS microphone line is no longer routed through the rear-installed head unit (A26/17) but is instead routed directly from the new double microphone to the telematics control unit (N112/9). The work instruction for implementation is attached to this document and must be completed in full. Operation steps from the attachment: • Slide 6: De-pin pins 19 and 6 from plug A at the head unit (A26/17), insulate and strap down. These lines are no longer needed. • Slide 7: Replace the front left microphone with the double microphone (A213 820 2801) (AR82.70-P-8969XG). Info: The installation location of the double microphone is always at the front left. There is no difference here between the right-hand drive or left-hand drive versions. • Slide 9: Pin the double microphone wiring harness at connector X58/3X1 at pin 1 (white) and pin 14 (shield). • Slide 10: De-pin the Hermes wiring harness at connector X58/3X1 pin 1 (black line) and pin the white line in its place. Connect to pin 14 (brown line). Insulate the black line and tie it back. • Slide 15: De-pin and strap down the existing lines at connector 1 on the HERMES (N112/9) from pin 29 (brown), pin 30 (white), and pin 31 (black). • Slide 16: Insert the brown line of the new wiring harness at pin 29 and the white wire at pin 30. Connect the shield (black line) to pin 31. After completion, please document the following FO text in Vehicle Documentation System: "Conversion to double microphone (A213 820 28 01) performed as per LI82.70-P-079903."
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| LI82.70-P-079903 | Service bulletin | Mar 7, 2026 | 11029928 | PDF, 43 KB |
| LI82.70-P-079903 | Service bulletin | Feb 13, 2026 | 11028817 | PDF, 42 KB |
| LI82.70-P-079903 | Service bulletin | Jan 2, 2026 | 11026968 | PDF, 42 KB |
| LI82.70-P-079903 | Service bulletin | Oct 20, 2025 | 11024406 | PDF, 35 KB |
What the document itself lists
Parts the bulletin names
| Part number | Description | Qty | Find it |
|---|---|---|---|
| A2138202801 | Double microphone 1 Required only for vehicles with a pro | — | eBay Motors → |
| A4658205807 | Repair wiring harness 1 Double microphone-OCP X | — | eBay Motors → |
| A4658205907 | Repair wiring harness 1 OCP-Hermes X | — | eBay Motors → |
Read by machine from the document NHTSA serves (3 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.
Affiliate disclosure: some links on this page are affiliate links. If you request a quote or buy through them we may earn a commission at no extra cost to you. Nothing on this page changes because of it.
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.
Email me new Mercedes-Benz bulletins for the G-Class
A weekly email, sent only in a week when Mercedes-Benz files something new with NHTSA for the model you pick — service bulletins, campaigns, warranty extensions, over-the-air notices, every model year. Nothing else is sent; one-click unsubscribe in every message. Separate from recall alerts.
What owners reported
Source: NHTSA complaint databaseOwners of the 6 model years this bulletin names have filed 26 complaints with NHTSA since 2015. 5 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.
Shortly after purchasing a new Mercedes Benz 2021 G550 on , the SUV started having electrical problems. During early 2022 the vehicle shut off while at a red light and would not restart until a few minutes later. No warning light or error message was seen and when taken to the dealership they could not find anything wrong.
2021 Mercedes-Benz G-Class · Electrical System · filed with NHTSA Jun 5, 2024 · ODI 11592609
Driving 2021 Mercedes-Benz G-550 for approximately 8min. Preceding East on a 3 lane South Florida Highway no more than 40 mph. Gas tank 75% full with V-Power From Shell. (filled-3 days prior).
2021 Mercedes-Benz G-Class · Electrical System · filed with NHTSA Sep 21, 2022 · ODI 11485579
Front Door harness rubs and frays causing the wires to short out. The front windows and door locks work intermittently. SRS failure lights up on dash
2021 Mercedes-Benz G-Class · Electrical System · filed with NHTSA Oct 1, 2026 · ODI 11768237
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 group39 other manufacturer communications filed against the Mercedes-Benz G-Class 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 |
|---|---|---|---|
| ANN - Tech. Aware. G580e | Other | Sep 21, 2026 | Tech. Awareness: G580e 465.600/465.601 - ISU For Model G580e 465.600/465.601 - Please be aware that initial start up of N147/10n1, N147/10n2… |
| LI54.10-P-080684 | Service bulletin | Sep 17, 2026 | Complaint When disconnecting or connecting the charging connector, the charging socket flashes red and red warning messages are displayed in… |
| LI54.21-P-080326 | Service bulletin | Sep 9, 2026 | Complaint CEL light on with no drivability concerns. Cause Signal timing error. Remedy 167, 465: SW has been released. Update the FSAM to th… |
| 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… |
| LI82.85-P-079087 | Service bulletin | Aug 6, 2026 | Complaint A popup is seen on the HU with the message "data connection temporarily not available". Potentially affected functionalities in NT… |
| PSL-NCU Return Parts 7/17 | Other | Jul 17, 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… |
| LI00.20-P-077615 | Service bulletin | Jul 1, 2026 | The following symptoms may be present in the instrument cluster: 1. "Perform vehicle handover" in the workshop menu to start the maintenanc… |
| LI00.20-P-080703 | Service bulletin | Jun 12, 2026 | Complaint Service code B1 displayed in the customer menu does not match the workshop code displayed in the workshop menu, e.g., 505 or 550A… |
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 LI82.70-P-079903 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 LI82.70-P-079903 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 LI82.70-P-079903 cover?
The manufacturer filed it against 6 model years: 2025 Mercedes-Benz G-Class, 2024 Mercedes-Benz G-Class, 2023 Mercedes-Benz G-Class, 2022 Mercedes-Benz G-Class, 2021 Mercedes-Benz G-Class, 2020 Mercedes-Benz G-Class. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.