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Service bulletin LI54.21-P-079369

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id11018707
Published by NHTSA2025-05-30
Manufacturer's numberLI54.21-P-079369
Manufacturer's date2025-05-30
NHTSA componentENGINE; ELECTRICAL SYSTEM

NHTSA's summary

Complaint The customer complains that there is a humming/droning/throbbing/ear pressure in the interior at low engine speeds (up to 2400 rpm). Cause In the current software state, the EOC system (Active Noise Cancellation), which reduces the humming in the interior, fails permanently, without a DTC (Diagnostic Trouble Code) being stored. Remedy Remedy software available in Xentry: • Vehicles with code 810: SW update ASX (N156/1) and SND (N40/3) control unit • Vehicles with code 811: SW update ASX (N156/1) and SND (N40/3) control unit After the ASX & SND software update, initial start up of the control units must be performed.

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Electrical system, Engine

Vehicles listed
MERCEDES-BENZ AMG GT 63 S E COUPE2023 (the catalog's model; the bulletin names a series or trim of it)
MERCEDES-BENZ AMG GT632019, 2020, 2021, 2022, 2023, 2024 (the catalog's model; the bulletin names a series or trim of it)
MERCEDES-BENZ AMG GT63 S2022, 2023 (the catalog's model; the bulletin names a series or trim of it)
MERCEDES-BENZ AMG GT63 S E2024, 2025 (the catalog's model; the bulletin names a series or trim of it)
MERCEDES-BENZ AMG GT63S2019, 2020, 2021 (the catalog's model; the bulletin names a series or trim of it)

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Recalls for the same vehicles and component
25V1290002025-02-28. ELECTRICAL SYSTEM:PROPULSION SYSTEM
20246152024-10-18. Electrical
24V4450002024-06-14. ELECTRICAL SYSTEM:WIRING
20241052024-02-16. Electrical
20240812024-02-09. Electrical
24V1000002024-02-09. ELECTRICAL SYSTEM:WIRING
23V5740002023-08-11. ELECTRICAL SYSTEM:ADAS:BLINDSPOT:SENSORS
20223972022-07-22. Electrical
22V5330002022-07-22. ELECTRICAL SYSTEM:WIRING
22V3650002022-05-20. COMMUNICATION: AUTO CRASH NOTIFICATION; ELECTRICAL SYSTEM:SOFTWARE

A recall listed here may apply to some of the same vehicles. Only the manufacturer can say whether it applies to one vehicle.

Other bulletins for the same vehicles and component
OTA-Comm. Mod. SW. Update2026-10-06. Over-the-air update. A software update will be performed that provides enhancements to the robustness and system stability of the communication module. The update is free of charge and runs in the background, which takes about 8 minutes to install. During this time, the vehicle can be driven without any restrictions, and the new software will be active with the next ignition cycle. Remedy MBUSA will conduct an OTA service campaign. Remote software updates are automatically downloaded and installed in the customer’s vehicle free of charge and do not require a dealer visit.
LI18.00-P-0731372026-10-06. Service bulletin. Complaint Sporadic warning message in instrument cluster "Engine oil pressure, stop switch off vehicle" (or similar) is shown in red on vehicles with low mileage. Cause Directional control valve may stick. Remedy 1‑ Read off oil level in instrument cluster and correct if necessary. 2‑ Perform approx. 10‑15 engine starts, then clear fault codes. 3‑ Perform road test with vehicle. If fault code reoccurs during road test: Install new directional control valve.
LI20.10-P-0753742026-10-06. Service bulletin. Complaint Red coolant warning in instrument cluster. Fault codes U019F00 or U019F87 current/stored in MRG1 control unit. Cause Various causes Remedy Perform guided test for fault code U019F with XENTRY diagnosis. Verify the following connections are clean and tight. Correct any problems and retest pump actuation: ‑12V plug at M75/11 ‑48V plug at M75/11 ‑48V connector X192/4 ‑Connections at 48V fuse box F153/2 ‑Sockets 1,2, and 5 at connector 2 of MRG1 control unit ‑M75/11 circuit 41 ground If actuation and above connections are OK, but resistance between M75/11 and engine block is less than 2 ohms or heat shield touching coolant pump, proceed with below steps. 1‑Modify engine insulation per attached instructions. 2‑Remove engine control module and measure continuity within control unit between connector 2 pin 1 and connector 6 pin 2. 2a‑If open circuit is found, replace engine control unit (MRG1) and perform initial startup. Refer to XENTRY parts information group 54/054 item 300. 3‑Clear faults and verify M75/11 operating normally.
LI54.71-P-0791042026-10-02. Service bulletin. Complaint Traffic sign symbol for "Traffic Sign Assist" is blinking in instrument cluster without obvious cause usually with one of the following scenarios: • Flashing without a speed limit ("‑ ‑"). • Flashing when current vehicle speed is under speed limit. • Flashing between US speed limit symbol and European speed limit symbol. NOTE: • Verify that the concern falls under one of the attachment videos. If not, then it is outside of the scope of this LI. • This also does not cover "Traffic Sign Inoperative" messages on the instrument cluster. Cause There are two identified reasons for this concern: 1. Country code information stored incorrectly at a particular geographic latitude range. 2. Incorrect reference data when the vehicle is started and a GPS signal is not immediately available. Remedy Update head unit software to latest version and the re‑check function in the same location. NOTE: Updated head unit software for AMG's has NOT been released yet. ETA 12/2026. If vehicle is still exhibiting one of the symptoms as described exactly as in the complaint section or as shown in the video attachments, open a TIPS case to the Body/Chassis/Entertainment inbox with the following: • Video of the concern. • Exact location (latitude and longitude is best)
LI54.21-P-0803262026-10-02. Service bulletin. Complaint CEL light on with no drivability concerns. Cause Signal timing error. Remedy 167, 465: SW has been released. Update the FSAM to the latest SW version. 290, 118, 243, 247: Software is still in development. This fault code does not cause a drivability concern and will clear itself within 2‑ 3 key cycles. The vehicle can be released back to the customer.
LI54.71-P-0791042026-09-02. Service bulletin. Complaint Traffic sign symbol for "Traffic Sign Assist" is blinking in instrument cluster without obvious cause usually with one of the following scenarios: • Flashing without a speed limit ("‑ ‑"). • Flashing when current vehicle speed is under speed limit. • Flashing between US speed limit symbol and European speed limit symbol. NOTE: • Verify that the concern falls under one of the attachment videos. If not, then it is outside of the scope of this LI. • This also does not cover "Traffic Sign Inoperative" messages on the instrument cluster. Cause There are two identified reasons for this concern: 1. Country code information stored incorrectly at a particular geographic latitude range. 2. Incorrect reference data when the vehicle is started and a GPS signal is not immediately available. Remedy Update head unit software to latest version and the re‑check function in the same location. If vehicle is still exhibiting one of the symptoms as described exactly as in the complaint section or as shown in the video attachments, open a TIPS case to the Body/Chassis/Entertainment inbox with the following: • Video of the concern. • Exact location (latitude and longitude is best)
LI01.20-P-0808842026-08-18. Service bulletin. Complaint Oil leaks found on M176 or M177 engines diagnosed to be from the cylinder head cover area Cause Unknown (under investigation) Remedy If oil leaks are found at left or right cylinder head cover area please collect the following information and open TIPS case. 1. Collect photos of the leak 2. Include close up and wide view photos to accurately represent the location 3. Include if the vehicle has a "check oil level" Light on in the cluster or fault codes 4. Check oil level as per WIS to verify level and calculate possible oil loss from the leak 5. Identify and communicate the severity of the leak and provide supporting documentation 6. Open a TIPS case with the above information and submit to the Powertrain team for processing
LI54.10-P-0808802026-08-14. Service bulletin. Complaint Customer Complaint: - AC charging is not possible. - The departure time, charging pause, location-based charging or target SOC limit is automatically set to 50% or to a random value in the Mercedes me application or in the charging settings on the head unit display. (Picture 1 & 3) - Incorrect notifications appear in the Mercedes me application for charging-related functions. (Picture 2) Related DTCs in quick test: No related fault codes (DTCs) are stored in the relevant control units. CPC3 - N127 (Drivetrain control unit) OBL223_GEN4 - N83/11 (Alternating current charger for high-voltage battery) DCB223 - N116/5 - Direct current charge connection unit (DCCU) Picture1 The target SOC limit is automatically set to 50% or any random values during charging. Picture 2 Incorrect notification Example “Unable to unlock charging cable. Picture 3 Incorrect settings of charge interruption or pause. (If applicable) Cause - The Customer shares their Mercedes me credentials (password) with a third-party application, for example, a wall box application. This causes the Mercedes Benz backend server to receive random requests to reset the maximum SOC, departure time, charging pause, etc. - Charging settings are set incorrectly, for example, incorrect departure time, charging program, charging interruption/ pause, etc. Remedy The remedies below may vary depending on the customer complaint. Refer to the remedy that best matches the customer complaint. Remedy 1: The target SOC limit is automatically set to 50% or to random values during charging. - Change the Mercedes me login password on the Mercedes me homepage. (My Account > Login and Security > Reset). (Refer to Annex 1). Previously granted authorizations should then be revoked so that the charging settings can no longer be changed by external applications. Advise customers not to share the new password again. - Are there any sub-users? If yes, revoke their rights and reassess the function. -If differences between the vehicle and the Mercedes me app are visible, a new synchronization is recommended. Turn off Digital Extras through the Mercedes me app or the MMCR portal, and then turn the services on again. Remedy 2: Incorrect notifications in the Mercedes me app for charging-related functions. - Restart synchronization between the app and backend. Turn off Digital Extras through the Mercedes me app or the MMCR portal, and then turn the services on again. (Refer to Annex 2) Remedy 3: Incorrect charge interruption or pause setting. - Perform a factory reset of the head unit (A26/17). (Home > Functions > System > Reset), or turn off/correct all charging settings. (Refer to Annex 3) Additional Information: (Good to know) The LED on the charging inlet or socket indicates whether charging is completed or paused. 1) If the target SOC is reached, the charging inlet LED lights up Blue/Green without flashing. 2) If charging is paused, the charging inlet LED lights up orange without flashing. Additionally, the head unit charging settings display a charging pause. Note: Do not replace any hardware components for these complaints. If the complaint cannot be solved, please contact via TIPS or CAC.
LI54.65-P-0801322026-08-12. Service bulletin. Complaint 1. General Diagnostic Tips 2. One or More PARK Sensor Activations 3. Red Ring Around Vehicle 4. "Active Parking and Parking Assist Inoperative" on Instrument Cluster 5. Cameras 6. Other Park Topics. Cause Various root causes Remedy See attached diagnostic guide.
LI82.60-P-0808062026-08-11. Service bulletin. Complaint DAB, FM, or SDARS radio reception is limited, only a few stations are found. Cause The firmware installation was incomplete. Remedy In the A26/17 control unit "MBUX multimedia system" (head unit), use XENTRY to carry out the special process "All Modules"; this will reinstall the firmware completely.