Emergency Call System, Function - GF82.95-P-0004LFM
Model 217, 222
as of model year 2018
with code 351 (eCall emergency call system)
except code 347 (Mercedes-Benz emergency call system)
except code 348 (Emergency call/assistant system)
except code 350 (Ecall emergency call system, Europe)
Shown on model 222, 217
Information on touchpad
The touchpad is installed in two variants.
Variant 1 (with code 448 (Touchpad)): The touchpad is installed together with the Audio/COMAND control panel. The touchpad is connected only to the telematics CAN.
Variant 2 (with code 446 (Touchpad only)): The touchpad is installed instead of the Audio/COMAND control panel. In this case, the lower control panel is connected via the LCP LIN to the touchpad. The touchpad is also connected to the telematics CAN.
Function requirements, general
- Circuit 30 ON
- 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 is spoken to in the language that is selected in the system settings of the head 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 message "Circuit 15" from the electronic ignition lock control unit over the diagnostic CAN, 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 the audio source mute function
- Connection to the driver hands-free system microphone, from the head unit
- Left emergency call system antenna
- Right emergency call system antenna (with code 362 (HERMES LTE))
- Connection to the multifunction antenna (on model 222) or to the GPS antenna (on model 217)
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, after switching off the ignition, the Supplemental Restraint System control unit switches to the "Sleep" mode, it no longer sends a readiness signal and the "SOS NOT READY" message is shown.
The electronic ignition lock control unit transmits the status of circuit 15 to the HERMES control unit via diagnostic CAN.
The emergency call system function includes 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), "sending data" (emergency call data transmission (data telegram)), "connected" (voice connection established))
- Emergency call forwarded to the local 112 rescue service (display of address or coordinates of vehicle position)
- 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 →
User interface CAN →
Head unit →
HSVL →
Audio/COMAND display
The head unit transmits a switch-on request via the telematics CAN to the Audio/COMAND display, processes the visualization, and transmits the picture data to the Audio/COMAND display via the HSVL line.
Some text messages on the Audio/COMAND display can be confirmed with the Audio/COMAND control panel (with code 448 (Touchpad)) or the touchpad (with code 446 (Touchpad only) or code 448 (Touchpad)). The Audio/COMAND control panel transmits the signals via the following route:
Telematics CAN →
Head unit →
User interface CAN →
Electronic ignition lock control unit →
Diagnostic CAN →
HERMES control unit
Status indication via light-emitting diode
The SOS button LED is used to indicate the following statuses:
- Active service, light-emitting diode flashes.
- Self-diagnosis of emergency call system, LEDs light for approx. 5 s.
- Fault in emergency call system, LEDs permanently on.
- Diagnosis
The HERMES control unit transmits the request to switch on the light emitting diode via the following route:
Diagnostic CAN →
Electronic ignition lock control unit →
Interior CAN →
SOS button of overhead control panel control unit (model 222, 217.3) →
SOS button of emergency call system button group (model 217.4)
The overhead control panel control unit controls the LED in the SOS button.
Status indication in instrument cluster
If the HERMES control unit fails, the message "SOS nonfunctional" is displayed in the instrument cluster. To do this, the HERMES control unit constantly transmits the system status via the following route:
Diagnostic CAN →
Electronic ignition lock control unit →
User interface CAN →
Instrument cluster
Position finding
On vehicles as of 01.06.2019, the HERMES control unit receives signals of the global navigation system (GPS) from the multifunction antenna (model 222) or from the GPS antenna (model 217).
On vehicles up to 31.05.2019, the HERMES control unit accepts the position finding signals from the head unit. The head unit receives GPS signals via the multifunction antenna (model 222) or via the GPS antenna (model 217). The head unit transmits the signals via the WLAN antenna to the 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, a data telegram containing updated position data is sent to the Mercedes-Benz Service Center, and the existing connection is maintained.
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
- Circuit 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 (eCall) is immediately sent. An emergency call is sent out regardless of the severity of the accident.
The HERMES control unit receives the crash information via the seat occupancy LIN 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:
User interface CAN →
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.
If the active emergency braking assistant (with code 23P (Driving Assistance package)) brakes the vehicle to a standstill, the Mercedes-Benz Intelligent Drive control unit transmits the automatic emergency call request via the following route:
Suspension FlexRay →
Electronic ignition lock control unit →
Diagnostic CAN →
HERMES control unit
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 SOS button.
The SOS 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 overhead control panel control unit transmits the status of the SOS button via the following route:
Overhead control panel 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 establishes a voice connection to the Mercedes-Benz Service Center via the following antenna connection:
Telephone antenna splitter (model 222) or emergency call system antenna splitter (model 217) →
Left emergency call system antenna and right emergency call system antenna (with code 362 (HERMES LTE)) and multifunction antenna (model 222) or telematics services antenna (model 217)
The antennas form a sending and receiving 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/End phone call switch on the multifunction steering wheel is temporarily disabled while the connection is being established to prevent the call being ended unintentionally.
While the connection is being set up, audio sources are muted (mute function) and existing telephone connections are interrupted.
In vehicles except code 810 (Sound system) and except code 811 (Advanced sound system), the HERMES control unit sends the signal for the mute function to the head unit.
In vehicles with code 810 (Sound system), the HERMES control unit sends the signal for the mute function to the sound system amplifier control unit.
In vehicles with code 811 (Advanced sound system), the HERMES control unit sends the signal for the mute function to the Advanced sound system amplifier control unit.
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 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 in the language that was selected in the system settings of the head unit and transmitted in the data telegram, where possible. The driver hands-free system microphone, which is installed on the driver side of the roof interior trim, is used for the voice input. 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 from the driver hands-free system microphone via the head unit.
The HERMES control unit outputs the incoming voice signals over the center instrument panel speaker (except code 811 (Advanced sound system)) or over the center instrument panel midrange speaker (with code 811 (Advanced sound system)).
The volume of the voice output can be adjusted using the following controls:
- Head unit multifunction steering wheel button group volume adjustment switch
- Volume adjustment button of the Audio/COMAND control panel (with code 448 (Touchpad)) or the lower control panel (with code 446 (Touchpad only))
The accept/terminate phone call switch in the head unit multifunction steering wheel button group can be used to end the emergency call if this is not done by the Mercedes-Benz Service Center.
The head unit multifunction steering wheel button group sends the control signals via the following route:
Steering wheel electronics →
Steering wheel CAN →
Steering column tube module control unit →
Suspension FlexRay →
Electronic ignition lock control unit →
User interface CAN →
Instrument cluster →
User interface CAN →
Electronic ignition lock control unit →
Diagnostic CAN →
HERMES control unit
The lower control panel (with code 446 (Touchpad only) transmits the control signal via the following route:
LCP LIN
Touchpad (with code 446 (Touchpad only)) →
Telematics CAN →
Head unit →
User interface CAN →
Electronic ignition lock control unit →
Diagnostic CAN →
HERMES control unit
The Audio/COMAND control panel (with code 448 (Touchpad)) transmits the control signals via the following route:
Telematics CAN →
Head unit →
User interface 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 head unit.
| Electrical function diagram for manual or automatic emergency call function | Model 217 as of model year 2018 with code 351 (eCall emergency call system) except code 347 (Mercedes-Benz emergency call system) except code 348 (Emergency call/assistant system) except code 350 (Ecall emergency call system, Europe) | PE82.95-P-2066-97SEN | |
| Model 222 as of model year 2018 with code 351 (eCall emergency call system) except code 347 (Mercedes-Benz emergency call system) except code 348 (Emergency call/assistant system) except code 350 (Ecall emergency call system, Europe) | PE82.95-P-2066-97SEM | ||
| Overview of system components, telematics | GF82.85-P-9999LFM |