Emergency Call System, Function - GF82.95-P-0004RRM
Model 190 as of 12/1/18
as of model year 2019
With Code 362 (HERMES communications module LTE)
Function requirements, emergency call system, general
- Circuit 30g
- 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. If possible, 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, it checks the operational readiness of the emergency call system. The electronic ignition lock control unit transmits the circuit 15 status via the following route:
Interior CAN →
Front SAM control unit with fuse and relay module →
Diagnostic CAN →
HERMES control unit
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 mute function (muting of audio sources)
- Connection to driver hands-free system microphone, from head unit
- Connection to emergency call system antenna
- Connection to left telephone antenna, right telephone antenna and telephone antenna splitter
- Connection to GPS antenna (with code 506 (Radio Audio 20 NTG 5.5))
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 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 (with code 531 (COMAND APS)) and the 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 →
Front SAM control unit with fuse and relay module →
Interior CAN →
AMG gateway control unit →
User interface CAN →
Head unit →
HSVL line →
Audio/COMAND display
The control communication (e.g. switch on) is sent by the head unit to the Audio/COMAND display via telematics CAN.
Some text messages on the Audio/COMAND display can be confirmed using the Audio/COMAND operating unit (except code 446 (Touchpad only)) or with the touchpad (with code 446 (Touchpad only) or with code 531 (COMAND APS)). The Audio/COMAND control panel or the touchpad sends the signals over the following route:
Telematics CAN →
Head unit →
User interface CAN →
AMG gateway control unit →
Interior CAN →
Front SAM control unit with fuse and relay module →
Diagnostic CAN →
HERMES control unit
Status indication via light-emitting diode
The LED of the SOS button is used to indicate the following states:
- Active service, light-emitting diode flashes
- Self-test of emergency call system, LED illuminates for approx. 5 s
- Fault in emergency call system, LED on permanently
- Diagnosis
The HERMES control unit actuates the light-emitting diode in the SOS button via a direct line.
Status indication in instrument cluster
The status of the emergency call system is displayed by a message in the phone menu of the instrument cluster in the following instances:
- Active service
- Fault in emergency call system
The HERMES control unit sends status signals over the following path:
Diagnostic CAN →
Front SAM control unit with fuse and relay module →
Interior CAN →
AMG gateway control unit →
User interface CAN →
Instrument cluster
Position finding
On vehicles with code 531 (COMAND APS) the HERMES control unit receives the position finding signals from the head unit. The head unit sends the signals via the following route:
User interface CAN →
AMG gateway control unit →
Interior CAN →
Front SAM control unit with fuse and relay module →
Diagnostic CAN →
HERMES control unit
On vehicles with code 506 (Radio Audio 20 NTG 5.5), the HERMES control unit performs position finding. 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. A basic position finding routine runs in parallel to the GPS position finding routine that makes it possible to also locate the position of the vehicle if GPS reception fails.
The position finding function consists of the following component functions:
- GPS position finding (With Code 506 (Radio Audio 20 NTG 5.5))
- Basic position finding (With Code 506 (Radio Audio 20 NTG 5.5))
GPS position finding (With Code 506 (Radio Audio 20 NTG 5.5))
The HERMES control unit receives the GPS signals from the GPS antenna.
Additional function requirements for basic position finding (With Code 506 (Radio Audio 20 NTG 5.5))
- Circuit 15 ON
Basic position finding (With Code 506 (Radio Audio 20 NTG 5.5))
The electronic ignition lock control unit transmits the circuit 15 status via the following route:
Interior CAN →
Front SAM control unit with fuse and relay module →
Diagnostic CAN →
HERMES control unit
The HERMES control unit requires the following signals for basic position finding:
- Wheel speed and yaw rate signals from the Electronic Stability Program control unit
- Steering wheel angle sensor
The Electronic Stability Program control unit sends the wheel speed and yaw rate signals as follows:
Chassis CAN 1 →
Front SAM control unit with fuse and relay module →
Diagnostic CAN →
HERMES control unit
The steering wheel angle sensor sends the signal as follows:
Steering column tube module control unit →
AMG FlexRay →
AMG gateway control unit →
Chassis CAN 1 →
Front SAM control unit with fuse and relay module →
Diagnostic CAN →
HERMES control unit
The HERMES control unit uses the data to calculate the current vehicle position (longitude and latitude).
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.
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 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
- 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 (E-call) is immediately sent. An emergency call is sent out regardless of the severity of the accident.
The supplemental restraint system control unit also (redundantly) sends the crash information via the following route:
Chassis CAN 1 →
Front SAM control unit with fuse and relay module →
Diagnostic CAN →
HERMES control unit
The HERMES control unit receives the crash information as a digital crash signal from the supplemental restraint system control unit.
The supplemental restraint system control unit sends a readiness signal in cycles (e.g. every 500 ms). 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 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 HERMES control unit reads in the signal from the SOS button via a direct line.
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 emergency call system antenna, the left telephone antenna, right telephone antenna and the telephone antenna splitter.
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. The HERMES control unit sends the signal for the mute function to the following components:
- Midline sound system amplifier control unit (except code 810 (Sound system) and except code 811 (Advanced Sound System))
- Sound system amplifier control unit (with code 810 (Sound system))
- Advanced Sound System amplifier control unit (with CODE 811 (Advanced Sound System))
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 outgoing voice signals from the driver hands-free system microphone via the head unit.
The HERMES control unit outputs the incoming voice signals via the center instrument panel mid-range speaker.
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" and "Head unit ON" switch in the right lower control panel
The head unit multifunction steering wheel button group sends the volume setting over the following route:
Steering wheel electronics →
Steering wheel CAN →
Steering column tube module control unit →
AMG FlexRay →
AMG gateway control unit →
Interior CAN →
Front SAM control unit with fuse and relay module →
Diagnostic CAN →
HERMES control unit
The right lower control panel sends the volume setting over the following route:
Drive Unit CAN →
Drive Unit control unit →
Audio LIN→
Audio/COMAND control panel (except code 446 (Touchpad only)) or Touchpad (with code 446 (Touchpad only)) →
Telematics CAN →
Head unit
User interface CAN →
AMG gateway control unit →
Interior CAN →
Front SAM control unit with fuse and relay module →
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.
The accept/terminate phone call button 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 signal via the following route:
Steering wheel electronics →
Steering wheel CAN →
Steering column tube module control unit →
AMG FlexRay →
AMG gateway control unit →
Interior CAN →
Front SAM control unit with fuse and relay module →
Diagnostic CAN →
HERMES control unit
| Electrical function diagram for manual or automatic emergency call function | PE82.95-P-2066-97HBD | ||
| Overview of system components, telematics | GF82.85-P-9999RR |