LEMON Manuals: Even more car manuals for everyone
Home >> Mercedes Benz >> 2020 >> SLC43 AMG Base >> Repair and Diagnosis >> Electrical >> Motors, Switches, Relays >> Electrical System - Body - 172 Chassis - 2 Of 5 >> Basic Knowledge >> Telematics Services Function >> Telematics Services Function - GF82.85-P-2060RDM

Telematics Services Function - GF82.85-P-2060RDM

Model 172.4 

as of model year 2017 up to model year 2019 

with code 360 (HERMES UMTS) 

except code 362 (HERMES communications module LTE) 

Model 172.4 

as of model year 2019 

with code 362 (HERMES communications module LTE) 

except code 494 (US version) 

G13848181Courtesy of MERCEDES-BENZ USA

Shown on model 172.4 

General telematics services function requirements 

General telematics services 

At the vehicle side, the telematics services are realized by the HERMES control unit via a cellular telephone system connection to the Service Center. The HERMES control unit transmits and receives the cellular telephone system signals via the emergency call system antenna.

For some services, the status of circuit 15 is taken into consideration.

The electronic ignition lock control unit transmits the signal via the following route:

Interior CAN →

Front SAM control unit →

Diagnostic CAN →

HERMES control unit

The telematics services function encompasses the following subfunctions:

IMPORTANT The emergency call, Internet connection and the transfer of real-time traffic data are described elsewhere.

Overview of basic services 

The following services are possible:

Overview of telematics services with code 11U (Remote Online) 

These app services allow the customer to use his terminals (e.g. Smartphone, tablet or PC) to transmit information and operating requests to the vehicle via the Service Center and receive up-to-date vehicle data that has been prepared by the app. For example, the following app service are available:

Additional function requirements for voice connection between vehicle and Service Center 

Voice connection between vehicle and Service Center 

The HERMES control unit sets up a voice connection with the Mercedes-Benz Service Center via the emergency call system antenna by selecting the reserved telephone book entry "MB-Contact".

IMPORTANT The setup of a voice connection to the Mercedes-Benz Service Center is aborted after several unsuccessful dialing attempts, and a corresponding message is shown on the Audio/COMAND display.

IMPORTANT Telematics services, e.g. the breakdown service, can also be triggered by the Service Center following an emergency call with the customer's consent. In this case, the voice connection that was set up for the emergency call is used again by means of transferring within the Service Center. The emergency call is then converted into a service with lower priority.

The voice connection function between the vehicle and the Service Center is split up into the following subfunctions:

Selection of telephone book entry "MB Contact" 

The permanently reserved telephone book entry "MB-Contact" can be selected using one of the following components:

The Audio/COMAND control panel control signals are forwarded via telematics CAN to the audio equipment.

The control signals of the multifunction steering wheel button groups are forwarded via the following route:

Steering wheel electronics →

Steering LIN →

Steering column tube module control unit →

Chassis CAN 1 →

Front SAM control unit →

Chassis CAN 2 →

Instrument cluster →

Interior CAN →

Audio equipment

The voice control system is activated on the left multifunction steering wheel button group. The voice control system is automatically switched off when the call is set up.

When the voice control system is active, the voice commands are picked up by the inside rearview mirror microphone and forwarded via a direct line to the COMAND controller unit.

IMPORTANT The individual voice commands are listed in the "Linguatronic operator's manual".

Connecting 

If the telephone book entry "MB Contact" has been selected, the audio equipment sends the request for establishing a voice connection via the following route:

Interior CAN →

Front SAM control unit →

Diagnostic CAN →

HERMES control unit

The HERMES control unit establishes a voice connection with the Service Center via the emergency call system antenna or the multifunction antenna (with code 362 HERMES LTE) and transmits vehicle data.

IMPORTANT The emergency call system antenna and the multifunction antenna are used to achieve a transmission and reception diversity.

Mute function 

When a voice connection is set up, the HERMES control unit sends a signal over a direct line for muting the audio sources to the following component, which then actuates the speaker system:

Hands-free 

The hands-free system is not available for telephone calls for the duration of the voice connection.

After a data telegram has been transmitted to the Mercedes-Benz Service Center, the user can speak to a service receptionist via the voice connection. The Mercedes-Benz Service Center carries out the call, where possible, in the language that was selected in the system settings of the audio equipment and transmitted in the data telegram.

The HERMES control unit receives the outgoing voice signals over the audio equipment from the inside rearview mirror microphone.

The HERMES control unit emits the incoming voice signals over the center instrument panel speaker (with code 810 (Sound system)) or over the emergency call speaker (except code 810 (Sound system)). The voice output volume can be adjusted using the + and - button, setting of specific functions and the volume control of the right multifunction steering wheel button group. The right multifunction steering wheel button group sends the control signals via the following route:

Steering wheel electronics →

Steering LIN →

Steering column tube module control unit →

Chassis CAN 1 →

Front SAM control unit →

Chassis CAN 2 →

Instrument cluster →

Interior CAN →

Front SAM control unit →

Diagnostic CAN →

HERMES control unit

Termination of the voice connection 

The voice connection can be terminated via the accept/terminate phone call button of the right multifunction steering wheel button group, if this is not carried out by the Mercedes-Benz Service Center.

The right multifunction steering wheel button group sends the control signals via the following route:

Steering wheel electronics →

Steering LIN →

Steering column tube module control unit →

Chassis CAN 1 →

Front SAM control unit →

Chassis CAN 2 →

Instrument cluster →

Interior CAN →

Front SAM control unit →

Diagnostic CAN →

HERMES control unit

Prioritization 

For the services that require a voice connection between the vehicle and the Service Center, the prioritization shown below is valid.

IMPORTANT Telematics services, e.g. accident management, can also be triggered by the Service Center after an emergency call with the customer's consent. In this case, the voice connection that was set up for the emergency call is used again by means of transferring within the Service Center. The emergency call is then converted into a service with lower priority.

Priority Service
1 Automatic emergency call
2 Manual emergency call
3 Breakdown Management
4 MB Info

Position finding 

A determination of the current vehicle position is essential for many telematics services. In vehicles with code 522 (Audio 20 radio) or with code 531 (COMAND APS) the HERMES control unit takes over the position finding signals from the audio equipment. The audio equipment sends the signals over the following path:

Interior CAN →

Front SAM control unit →

Diagnostic CAN →

HERMES control unit

In vehicles with code 505 (Radio 20 NTG5 non-navigation-capable) the position finding is conducted by the HERMES control unit. For position finding, the HERMES control unit uses the global navigation system (GPS). GPS is available worldwide. GPS position finding is irretrievable after vehicle transport (e.g. by train or ferry or after towing). Recalculation of the GPS position (following an interruption in satellite reception) can take several minutes. At the same time as the GPS position finding the HERMES control unit conducts a permanent basic position finding, that enables the position of the vehicle to be determined even when the GPS reception fails.

The position finding function consists of the following component functions:

GPS position finding (with code 505 (Radio 20 NTG5 non-navigation-capable)) 

The HERMES control unit receives the GPS signals from one of the following components:

Additional function requirements for basic position finding (with code 505 (Radio 20 NTG5 non-navigation-capable)) 

Basic position finding (with code 505 (Radio 20 NTG5 non-navigation-capable)) 

The HERMES control unit requires the following signals for basic position finding:

The Electronic Stability Program control unit sends the wheel speed and yaw rate signals as follows:

Chassis CAN 1 →

Front SAM control unit →

Diagnostic CAN →

HERMES control unit

The steering wheel angle sensor sends the signal over the following path:

Steering column tube module control unit →

Chassis CAN 1 →

Front SAM control unit →

Diagnostic CAN →

HERMES control unit

The HERMES control unit uses the data to calculate the current vehicle position (longitude and latitude).

IMPORTANT Position finding errors, rolling backwards with "circuit 15 OFF" (ignition switched off) or transport of the vehicle falsify the basic position finding. In both cases, this deviation is automatically corrected on receipt of GPS data.

Forwarding of vehicle data, display messages, data queries and operating requests 

The HERMES control unit forwards the data queries and operating requests that have been received via the mobile radio connection to the Service Center via the diagnostic CAN to the front SAM control unit. The HERMES control unit receives vehicle data from the front SAM control unit via the diagnostic CAN, and forwards this data and the data of the integrated position finding module via the emergency call system antenna to the Service Center in accordance with requirements.

The content shown on the Audio/COMAND display (e.g. pop-up-window, vehicle positioning symbol) is transmitted by the HERMES control unit via the following route:

Diagnostic CAN →

Front SAM control unit →

Interior CAN →

Audio equipment →

LVDS line →

Audio/COMAND display

The audio equipment transmits control signals via the telematics CAN to the Audio/COMAND display.

Some messages on the Audio/COMAND display can be confirmed with the Audio/COMAND control panel. The Audio/COMAND control panel sends the signals via the following route:

Telematics CAN →

Audio equipment →

Interior CAN →

Front SAM control unit →

Diagnostic CAN →

HERMES control unit

  Electrical function schematic for telematics services function   PE82.95-P-2074-97TAC
  Overview of system components, telematics   GF82.85-P-9999RD