2021 Mercedes-Benz AMG GT Digital Extras Not Activating

Owners of the 2021 Mercedes-Benz AMG GT, and other Mercedes-Benz model series equipped with the N112/9 (HERMES) or N112/2 (RAMSES) telematics control units, may encounter issues with their AMG GT Digital Extras (previously known as Mercedes me) failing to activate after a control unit replacement. This technical service bulletin (TSB L182.85-P-078473, Version 2, dated 11/20/24) addresses the problem where Digital Extras cannot be activated following the replacement of these specific telematics control units.

Symptoms

If your AMG GT Digital Extras are not activating, you might observe several indicators in your vehicle's instrument cluster or diagnostic system:

• The message "SOS - service not activated" may permanently illuminate in the instrument cluster. This indicates a problem with the telematics service activation, though the emergency call function itself remains operational.
• During diagnostic checks, the actual value "Error when replacing certificate (CEP.36)" is displayed under the "Registration status" for the telematics system.
• For vehicles with the N112/9 (HERMES) control unit, the control unit log may display the registration error "CEP Invalid VIN/UniqueID combination".
• For vehicles with the N112/2 (RAMSES) control unit, the control unit log may show the registration error "CEP_VIN_UNIQUEID_INVALID".
• General symptoms related to telematics services include the system reporting that the control unit cannot be activated/deactivated, the telematics service cannot be activated/deactivated, or displaying a "No connection possible" message.

Fault Codes / DTCs

This issue is typically accompanied by a specific diagnostic trouble code, which will be active or active+saved in the vehicle's system:

| Code | Description