April 2026 Mercedes-Benz AMG GT Service Bulletin Roundup

April 2026 brought no new recalls, owner complaints, or federal investigations for the Mercedes-Benz AMG GT across all model years. Instead, the month was marked by a significant number of Mercedes-Benz AMG GT service bulletins, predominantly for the 2021 model year. These technical documents from Mercedes-Benz provide crucial guidance for diagnosing and resolving various issues, with a notable pattern emerging around electrical system components. Specifically, multiple bulletins addressed parking assist system malfunctions, including messages like 'Active Parking and Parking Assist Inoperative' as detailed in TSB LI54.65-P-080132.

Recalls

No new recalls were filed for the Mercedes-Benz AMG GT in April 2026.

Owner Complaints

No new owner complaints were reported for the Mercedes-Benz AMG GT in April 2026.

Investigations

No new NHTSA investigations were opened, upgraded, or closed for the Mercedes-Benz AMG GT in April 2026.

Service Bulletins

This month's roundup of Mercedes-Benz AMG GT service bulletins highlights several key areas of concern and resolution for owners and technicians. The 2021 model year was particularly active, with multiple technical service bulletins (TSBs) issued to address various operational and electrical system issues.

Parking Assist System Malfunctions

Several bulletins focused on issues with the parking assist system in the 2021 Mercedes-Benz AMG GT. Owners reported various symptoms, including unexpected sensor activations, a 'Red Ring Around Vehicle' warning, and the critical message 'Active Parking and Parking Assist Inoperative'. Mercedes-Benz TSB LI54.65-P-080132 provides comprehensive diagnostic guidance for these complex parking system malfunctions, helping technicians pinpoint the root cause of the PARK sensor-related issues.

Digital Extras Not Activated

For 2021 Mercedes-Benz AMG GT vehicles, a common issue after a communication module replacement is the display of messages such as 'Digital Extras not activated' or 'SOS - service not activated'. This condition is frequently accompanied by diagnostic trouble code (DTC) B15CE00. Technical Service Bulletin LI82.85-P-078473 explains the underlying cause and outlines the necessary remedy to reactivate these digital services.

Engine Control Unit Software Update

An important service campaign, NCU - 2024100016, was issued to update the Engine Control Unit (ECU) software on certain 2021 Mercedes-Benz AMG GT vehicles. This update ensures the ECU software adheres to current production specifications, which is vital for preventing potential issues related to on-board diagnostics and exhaust gas emissions. Owners of affected vehicles should ensure this software update is performed.

Technical Reference Guide

Mercedes-Benz also released a comprehensive technical reference guide, LI00.01-P-078887, for the 2021 Mercedes-Benz AMG GT. This bulletin serves as a valuable resource for workshops, detailing common acronyms, methods for identifying control units, network/wiring architecture groups, and mappings between platforms and baumuster numbers. This type of reference material is crucial for accurate diagnosis and repair procedures.

What Mercedes-Benz AMG GT Owners Should Do

If you own a 2021 Mercedes-Benz AMG GT and experience any of the issues described in these service bulletins, here are some recommended steps:

• Monitor Warning Messages: Pay close attention to any dashboard warnings, especially those related to parking assist systems like 'Red Ring Around Vehicle' or 'Active Parking and Parking Assist Inoperative', or messages about 'Digital Extras not activated'.
• Check for Software Updates: If you notice any unusual engine behavior or receive a Check Engine Light (CEL), particularly with DTC P012800 (coolant temperature below specification), contact your dealer to inquire about available software updates, including the ECU software update campaign NCU - 2024100016.
• Address Call Quality Issues: If you experience poor voice quality or excessive background noise during phone calls, mention this to your service center, as it could be related to improperly seated microphones as outlined in TSB LI82.70-P-077433.
• Consult Your Dealer: For any persistent electrical system issues or warning messages, schedule an appointment with an authorized Mercedes-Benz service center. Provide them with details of the symptoms and any specific messages or diagnostic trouble codes you've observed. They can access the latest Mercedes-Benz AMG GT service bulletins and apply the appropriate diagnostic and repair procedures.