Emergency Call System, Function - GF82.95-P-0004GWA
Model 463
as of model year 2017 up to model year 2019
with code EK1 (HERMES communications module LTE)
Model 463
as of model year 2017 up to model year 2019
with code EM2 (Communications module (UMTS) for the use of Merced)
Function requirements, emergency call system, general
- Circuit 30
- Transport mode not active
- The communications module of the HERMES control unit is configured with the telephone number of the relevant service provider
Emergency call system, general
The emergency call system allows a manual or automatic emergency call to be triggered. The emergency call is received by the Mercedes-Benz Service Center. The user, where possible, is spoken to in the language that is selected in the system settings of the COMAND controller unit. If necessary, the Mercedes-Benz Service Center notifies the local rescue services. If the Mercedes-Benz Service Center is not staffed, the emergency call is automatically forwarded to the local rescue services 112.
If the HERMES control unit receives the CAN message "Circuit 15" from the electronic ignition lock control unit, it checks the operational readiness of the emergency call system. After a successful check, the emergency call system is operational and "SOS ready" appears on the Audio/COMAND display. The following checks are carried out:
- Receipt of cyclic readiness signal ("sign of life") from the Supplemental Restraint System control unit
- Connection for muting audio sources (mute function)
- Connection to the hands-free system microphone from the COMAND controller unit
- Connection to the emergency call system antenna 1
- Connection to the emergency call system antenna 2
In the event of a fault, depending on the fault type, a fault message appears on the Audio/COMAND display and the fault is stored in the fault memory of the HERMES control unit. If the supplemental restraint system control unit goes into sleep mode after switching off the ignition, it no longer sends a readiness signal and the message "SOS not ready" is shown.
The electronic ignition lock control unit sends the message "Circuit 15" via diagnostic CAN to the HERMES control unit.
The emergency call system function comprises the following subfunctions:
- Emergency call system status indication
- Position finding
- Manual or automatic emergency call
Emergency call system status indication
The status of the emergency call system is shown in the following ways:
- Status indication on the Audio/COMAND display
- Status indication via light-emitting diode
- Status indication in instrument cluster
Status indication on the Audio/COMAND display
The status of the emergency call system is indicated by a text message on the Audio/COMAND display in the following cases:
- Emergency call system operational or not operational ("SOS ready" or "SOS not ready" in telephone menu)
- Emergency call has been activated ("activating" (call setup), "transmitting data" (data telegram transmission), "connected" (voice connection established))
- Emergency call forwarded to local 112 rescue services (the address and coordinates of the vehicle position are also shown)
- Call activation has failed several times ("MB emergency call processing failed. Please dial 112 on the mobile phone.")
If an emergency call is active, the top right of the Audio/COMAND display also shows a telephone symbol, an emergency call symbol and the field strength of the HERMES control unit.
The HERMES control unit sends the display over the following path:
Diagnostic CAN →
Electronic ignition lock control unit →
Interior CAN →
COMAND controller unit →
LVDS line →
Audio/COMAND display
Control communication (e.g. switch-on) is sent by the COMAND controller unit over the telematics CAN to the Audio/COMAND display. Some text messages on the Audio/COMAND display can be confirmed using the Audio/COMAND control panel. The Audio/COMAND control panel sends the signals via the following route:
Telematics CAN →
COMAND controller unit →
Interior CAN →
Electronic ignition lock control unit →
Diagnostic CAN →
HERMES control unit
Status indication via light-emitting diode
The LED of the emergency call system button is used to indicate the following status:
- Active service, light-emitting diode flashes
- Diagnosis
- Self-test of emergency call system, LEDs light for approx. 5 s
During the emergency call system self-test the LEDs in the breakdown assistance button (S93/3s4) and the MB-Info button (S93/3s5) are also actuated.
The HERMES control unit actuates the LED over the following path:
Diagnostic CAN →
Electronic ignition lock control unit →
Interior CAN →
SAM control unit →
Roof LIN →
Overhead control panel control unit →
Emergency call system button
Status indication in instrument cluster
If the HERMES control unit fails, the instrument cluster shows "SOS nonfunctional". The failure of the HERMES control unit is reported over the following path:
Diagnostic CAN →
Electronic ignition lock control unit →
Chassis CAN 2 →
Instrument cluster
Position finding
The HERMES control unit takes over the position finding signals from the COMAND controller unit. The COMAND controller unit sends the signals over the following path:
Interior CAN →
Electronic ignition lock control unit →
Diagnostic CAN →
HERMES control unit
Manual or automatic emergency call
In an emergency situation, a service receptionist from the Mercedes-Benz Service Center can obtain an overview of the condition inside the vehicle with the aid of the data received from the HERMES control unit (voice connection and data telegram) and initiate appropriate help measures. An emergency call be initiated manually or automatically.
These emergency calls are made for the following reasons:
- Automatic alerting of the rescue services after an accident
- Alerting rescue services by pushing a button (own emergency situation, observed accident)
- Reduction in rescue times through fast emergency notification with details on exact location involved
The automatic emergency call has priority over a manually triggered emergency call. If an automatic emergency call is triggered during a manual emergency call, the manual emergency call is interrupted. If a manual emergency call is triggered during an automatic emergency call, it is ignored. However (while the existing connection is maintained) a data telegram containing updated position data is sent to the Mercedes-Benz Service Center.
The manual or automatic emergency call function consists of the following subfunctions:
- Triggering of an automatic emergency call
- Triggering of a manual emergency call
- Voice connection between vehicle and Service Center
Additional function requirements for triggering an automatic emergency call
- Terminal 15 ON
Triggering of an automatic emergency call
In the event of an accident with deployment of the restraint systems (not the PRE-SAFE® system) an automatic emergency call (E-call) is immediately sent. An emergency call is sent out regardless of the severity of the accident.
The HERMES control unit receives the crash information over a direct line as a digital crash signal from the supplemental restraint system control unit.
The supplemental restraint system control unit also (redundantly) sends the crash information, including crash level, via the following route:
Chassis CAN 1 →
Electronic ignition lock control unit →
Diagnostic CAN →
HERMES control unit
The supplemental restraint system control unit transmits a readiness signal cyclically (e.g. every 500 ms) via the same route as crash information. This enables the HERMES control unit to monitor communication with the supplemental restraint system control unit and correct operation of the crash detection.
Additional function requirements for triggering a manual emergency call
- No automatic emergency call is active.
Triggering of a manual emergency call
The manual emergency call is triggered by pressing the emergency call system button. The emergency call system button is covered up with a locking flap. Pressing the protective lid unlocks the lid, and it automatically opens with the aid of a spring mechanism.
The signals from the emergency call system button are sent over the following path:
Overhead control panel control unit →
Roof LIN →
SAM control unit →
Interior CAN →
Electronic ignition lock control unit →
Diagnostic CAN →
HERMES control unit
Voice connection between vehicle and Service Center
Once the emergency call has been triggered, the HERMES control unit sets up a voice connection to the Mercedes-Benz Service Center via the emergency call system antenna 1 and the emergency call system antenna 2.
Emergency call system antenna 1 and emergency call system antenna 2 are used to set up the connection in order to form transmission and reception diversity.
The status of the connection setup is indicated by the following messages on the Audio/COMAND display:
- "Activating" (setting up the call)
- "Transmitting data" (transmission of emergency call data (data telegram))
- "Connected" (voice connection established)
Establishing a voice connection to the Mercedes-Benz Service Center is canceled after several failed attempts to connect, and the following message is shown on the Audio/COMAND display: "MB emergency call activation failed. Please dial 112 on the mobile phone."
During an automatic emergency call, the accept/terminate phone call button on the multifunction steering wheel is temporarily disabled while the connection is being set up in order to avoid unintentional termination.
While the connection is being set up, audio sources are muted (mute function) and existing telephone connections are interrupted.
On vehicles with code EU9 (Harman Kardon® Logic 7® Surround Sound System), the HERMES control unit transmits the signal for the mute function to the sound system amplifier control unit. The sound system amplifier control unit then stops playback of the audio signals that it receives via MOST.
On vehicles except code EU9 (Harman Kardon® Logic 7® Surround Sound System), the HERMES control unit transmits the signal for the mute function to the COMAND controller unit. The COMAND controller unit then stops playing back the audio signals.
As soon as a connection is set up to the Mercedes-Benz Service Center, the HERMES control unit automatically sends a data telegram to the Service Center. The data telegram transmits the following data:
- Time stamp
- GPS position of vehicle
- Language
- Vehicle identification number
- MB Contact status (ON or OFF)
- Position history (Tracing of vehicle positions up to a distance of a few 100 m from current location)
- Number of vehicle occupants (estimated)
After a data telegram has been sent to the Mercedes-Benz Service Center, the user can speak to a service receptionist through 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 COMAND controller unit and sent in the data telegram. The hands-free system microphone, which is integrated into the inside rear-view mirror (A67), is used for voice commands. The hands-free system is not available for telephone calls throughout the duration of the emergency call.
The HERMES control unit receives the outgoing voice signals of the hands-free system microphone via the COMAND controller unit.
The HERMES control unit outputs the incoming voice signals over the center instrument panel speaker.
The voice output volume can be adjusted using the right multifunction steering wheel button group.
The Accept/terminate phone call button on the multifunction steering wheel of the right multifunction steering wheel button group can be used to terminate the emergency call, if this is not done 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 →
Electronic ignition lock control unit →
Chassis CAN 2 →
Instrument cluster →
Interior CAN →
Electronic ignition lock control unit →
Diagnostic CAN →
HERMES control unit
With a manual or an automatic emergency call, the Service Center can transfer the map data to the vehicle if required. The data is made available to the navigation module of the COMAND controller unit.
| Electrical function diagram for manual or automatic emergency call function | PE82.95-P-2066-97ZGD | ||
| Overview of system components, telematics | GF82.85-P-9999GW |