Emergency Call System, Function - GF82.95-P-0004RFU
Model 205
up to model year 2017
with code 348 (Emergency call/assistant system)
except code 347 (Mercedes-Benz emergency call system)
Model 253
up to model year 2017
with code 348 (Emergency call/assistant system)
Shown on model 205, 253
Function requirements, emergency call system, general
- Circuit 30
- Transport mode not active
- Each vehicle-related service is authorized separately.
- The communication module of the emergency call system control unit is configured with the telephone number of the relevant service provider.
- The vehicle owner is registered and authorized at the Service Center.
Emergency call system, general
The emergency call system control unit enables the following vehicle-related services to be realized:
- Authorization ("provisioning")
- Manual or automatic emergency call
- MB information call
- Roadside assistance
- Notification in the event of anti-theft alarm ("Anti Theft Notification")
- Vehicle tracking
- Vehicle remote unlocking
- Vehicle remote locking
- Remote diagnosis ("Remote Diagnosis")
- Transmission of vehicle position ("Vehicle Locator")
- Notification of a certain speed being exceeded ("Speed Alert")
- Notification if a certain area has been reached or left ("Geo Fencing")
- Transmission of information (e.g. map data) to the vehicle ("Remote Information Feed")
- Transmission of updates to vehicle ("Remote Update")
- Visual and acoustic vehicle recognition ("Flash Lights and Sound Horn")
- Internet connection (with CODE 531 (COMAND APS))
The emergency call system control unit is not used for regular telephone calls.
The emergency call system function consists initially of the following subfunctions:
- Self-diagnosis
- Emergency call system status indication
- Telephone antenna selection
- Voice connection between vehicle and Service Center
- Position finding
- Data from the supplemental restraint system control unit
- Manual or automatic emergency call
A further subfunction is described in a separate document:
- Additional telematics services function
The Internet connection is not controlled via the emergency call system control unit, but via the head unit. Information on prioritization of services will be provided at the end of this document.
Self-diagnosis
If the emergency call system control unit receives the "Circuit 15R" message from the electronic ignition lock control unit, the emergency call system control unit runs a self-diagnosis (approx. 8 to 10 s). The light-emitting diodes of the SOS button, the MB-Info button and the breakdown assistance button are on for approx. 10 s.
The emergency call system control unit receives the "Circuit 15R" message via the diagnostic CAN from the electronic ignition lock control unit. After a successful self-diagnosis, the emergency call system is operational and the light-emitting diodes go out.
In the event of a fault, a fault message (depending on the fault type) appears on the instrument cluster and the LEDs on the SOS button, the MB-Info button and the breakdown assistance button are permanently illuminated. Depending on the fault type, the fault is also stored in the emergency call system control unit's fault memory.
Emergency call system status indication
The status of the emergency call system is shown in the following ways:
- Status indication through light-emitting diodes
- Status indication in instrument cluster
- Status indication on the Audio/COMAND display
With some services, no system-specific status indication takes place in the vehicle.
Status indication through light-emitting diodes
The LEDs for the SOS button, the MB-Info button and the breakdown assistance button are used to display the following states:
- Self-diagnosis of emergency call system, LEDs light up for approx. 10 s.
- Active service, each LED flashes on and off.
- Fault in emergency call system, LEDs permanently on.
- System readiness of emergency call system, LEDs are off.
- Diagnosis
The emergency call system control unit actuates the LEDs in the SOS button, the MB-Info button and the breakdown assistance button via the following route:
Diagnostic CAN →
Electronic ignition lock control unit →
Interior CAN →
Front SAM control unit →
Roof LIN →
Overhead control panel control unit
Status indication in instrument cluster
The status of the emergency call system is indicated in a text message in the instrument cluster in the following instances:
- Active service
- Fault in emergency call system
The emergency call system control unit forwards this display over the following route:
Diagnostic CAN →
Electronic ignition lock control unit →
User interface CAN →
Instrument cluster
Status indication on the Audio/COMAND display
An active service of the emergency call system is indicated by a text message or a pop-up window (with confirmation prompt) on the Audio/COMAND display.
The message or the pop-up window is displayed by the emergency call system control unit over the following route:
Diagnostic CAN →
Electronic ignition lock control unit →
User interface CAN →
Head unit →
LVDS line →
Audio/COMAND display
Additional function requirements for selecting the telephone antenna
- Defect in left telephone antenna or right telephone antenna or poor reception
Telephone antenna selection
Normally, the communications module integrated in the emergency call system control unit transmits and receives all mobile phone signals via the left telephone antenna or right telephone antenna and the telephone antenna splitter. In the event of poor reception or a defective left telephone antenna or right telephone antenna and telephone antenna splitter, the communications module integrated into the emergency call system control unit automatically transmits and receives the mobile phone signals via the emergency call system antenna.
The emergency call system control unit monitors the left telephone antenna or right telephone antenna and the telephone antenna splitter via a direct line and detects the failure or poor reception. The emergency call system control unit then automatically transmits or receives the mobile phone signals for each vehicle-related service via the emergency call system antenna.
Additional function requirements for voice connection between vehicle and Service Center
One of the following vehicle-related services is present:
- Manual or automatic emergency call
- MB information call
- Roadside assistance
- Vehicle tracking
Voice connection between vehicle and Service Center
Regardless of the type of vehicle-related service initiated (e.g. MB-Info call), a voice connection is established to the Service Center. Following feedback from the Service Center via a special tone, an SMS is sent to the Service Center. This message contains the vehicle position, customer and vehicle identification data and other vehicle data ("Initial Summary"). Then the user can speak to a service receptionist via the existing voice connection.
The hands-free system microphone is used for the voice input. The signals from the hands-free system microphone are transferred to the head unit, where they are looped through and forwarded to the communications module integrated into the emergency call system control unit. The communication module integrated into the emergency call system control unit then transmits the hands-free system microphone signals to the Service Center. The communications module integrated into the emergency call system control unit transmits and receives the mobile phone signals via the left telephone antenna or right telephone antenna and the telephone antenna splitter.
In the event of a failure of the left telephone antenna or right telephone antenna and telephone antenna splitter or poor reception, the emergency call system control unit automatically transmits and receives the mobile phone signals via the emergency call system antenna.
The establishment of a voice connection to the Service Center is interrupted by the communication module integrated into the emergency call system control unit after several unsuccessful dialing attempts. The cancellation of the connection setup is indicated by a corresponding message in the instrument cluster as well as on the audio/COMAND display. Voice output takes place exclusively via the center instrument panel speaker. The center instrument panel speaker is controlled by the emergency call system control unit via direct lines. The center instrument panel speaker and all other speakers installed depending on the equipment are muted by means of a mute signal from the emergency call system control unit for all other applications (e.g. audio mode).
In vehicles except CODE 810 (Sound system), the mute signal is transmitted via a direct line to the head unit. In vehicles with CODE 810 (Sound system), the mute signal is transmitted via a direct line to the sound system amplifier control unit. Normally, the voice connection is terminated by the Service Center or by the user.
In the event of an emergency call, the voice connection can only be terminated by the Service Center or by using the right multifunction steering wheel button group to terminate the telephone connection for at least 15 s.
Position finding
For position finding, the emergency call system control unit uses the satellite supported global navigation system (GPS) positioning system. GPS is available worldwide. GPS position finding is irretrievable after vehicle transport (e.g. by train or ferry or after towing). Relocating with GPS (after interruption of satellite reception) may require several minutes (for initial commissioning of the emergency call system control unit up to 20 minutes). Basic position finding runs parallel to GPS position finding.
The position finding function consists of the following component functions:
- GPS position finding
- Basic position finding
Additional function requirement for GPS position finding
- Circuit 15R ON or activation of an authorized service
GPS position finding
The GPS receiver integrated in the emergency call system control unit receives the GPS signals via the global positioning system antenna splitter. The emergency call system control unit calculates the current position of the vehicle (recipient) from the GPS signals. The vehicle's direction of travel is also determined using the sequence of GPS calculated locations.
Additional function requirement for basic position finding
- Circuit 15R ON
Basic position finding
For basic position finding, the emergency call system control unit requires wheel speed and yaw rate signals from the Electronic Stability Program control unit.
The Electronic Stability Program control unit sends the wheel speed and yaw rate signals over the following route:
Chassis FlexRay →
Electronic ignition lock control unit →
Diagnostic CAN →
Emergency call system control unit
The emergency call system control unit uses the data to calculate the current vehicle position (longitude and latitude).
Location errors in position finding, rolling backwards with "circuit 15 OFF" (ignition switched off) or transport of the vehicle falsify the basic position finding. In both instances, the deviation is automatically corrected by the navigation processor integrated into the emergency call system control unit when it receives GPS data.
Additional function requirement for data from the Supplemental Restraint System control unit
- Circuit 15R ON
Data from the supplemental restraint system control unit
In the event of an accident with airbag deployment, an automatic emergency call (E-Call) is made immediately. An emergency call is sent out regardless of the severity of the accident. The emergency call system 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 →
Emergency call system control unit
The supplemental restraint system control unit transmits a "LIFE" signal ("sign of life" of supplemental restraint system (SRS) control unit) via the same route as the crash information, incl. "crash level", every t = 500 ms. This allows the emergency call system control unit to permanently monitor communication with the supplemental restraint unit control unit and proper function of the crash recognition.
Manual or automatic emergency call
In the event that a driver is confronted with an emergency situation while in a remote location, a Service Center employee can obtain an overview of the situation inside the vehicle with the aid of the data received from the emergency call system control unit (voice connection and SMS) and initiate the appropriate action required for help. 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 of rescue workers at the press of a button (own emergency situation, observed accident)
- Reduction in rescue times through fast emergency notification with details on exact location involved
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.
In the event of an emergency call, the voice connection can only be terminated by the Service Center or by using the right multifunction steering wheel button group to terminate the telephone connection for at least 15 s. The signal is transmitted from the right multifunction steering wheel button group via the following route:
Steering wheel electronics →
Steering LIN →
Steering column tube module control unit →
Chassis FlexRay →
Electronic ignition lock control unit →
User interface CAN →
Instrument cluster →
User interface CAN →
Electronic ignition lock control unit →
Diagnostic CAN →
Emergency call system control unit
The emergency call function consists of the following subfunctions:
- Triggering of a manual emergency call
- Triggering of an automatic emergency call
- Transmission of the emergency call data and communication with the Service Center
Additional function requirements for triggering a manual emergency call
- A higher-priority vehicle-related service (automatic emergency call) is not 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 status of the SOS button is forwarded over the following route:
Overhead control panel control unit →
Roof LIN →
Front SAM control unit →
Interior CAN →
Electronic ignition lock control unit →
Diagnostic CAN →
Emergency call system control unit
Triggering of an automatic emergency call
The HERMES control unit receives a crash signal over the seat occupancy LIN from the supplemental restraint system control unit.
The supplemental restraint system control unit also (redundantly) sends the crash signal, including crash level over the following route:
User interface CAN →
Electronic ignition lock control unit →
Diagnostic CAN →
Emergency call system control unit
Transmission of the emergency call data and communication with the Service Center
After a manual or automatic emergency call has been initiated, the emergency call system control unit establishes a voice connection to the Service Center. After the Service Center replies with a special tone, the emergency call system control unit automatically transmits an SMS to the Service Center via the integrated communications module.
The SMS automatically sent to the Service Center contains the following data:
- Vehicle position, direction of travel and history
- Vehicle data and crash information
The communications module integrated into the emergency call system control unit transmits and receives the mobile phone signals via the left telephone antenna or right telephone antenna and the telephone antenna splitter.
In the event of a manual or automatic emergency call, other vehicle-related services (e.g. MB-Info call) are interrupted.
In the event of a failure of the left telephone antenna or right telephone antenna and telephone antenna splitter or poor reception, the emergency call system control unit automatically transmits and receives the mobile phone signals via the emergency call system antenna.
If connection to the Service Center cannot be established when an automatic emergency call is initiated, a voice connection is automatically set up using the emergency number whereupon the listed data then has to be communicated verbally.
Prioritization
The emergency call system control unit can manage a voice or data connection and an SMS connection at the same time. The data connection can be used by several services simultaneously by means of transmitting data packets at staggered times. The priority management is based on the following principles:
- Services with SMS capability are executed by SMS if one of the four services with the highest priority is activated and the remaining connection resources are released for the prioritized service.
- Services without SMS capability or an Internet connection are terminated if one of the four services with the highest priority is activated and the connection resources are released for the prioritized service.
- The data recording for remote diagnosis has its own data channel and it can be conducted in addition to any other service.
- The four services with the highest priority are executed if no service with a higher priority is active.
Services with SMS capability are:
- Vehicle tracking
- Vehicle remote unlocking
- Vehicle remote locking
- Notification of a certain speed being exceeded ("Speed Alert")
- Notification if a certain area has been reached or left ("Geo Fencing")
- Visual and acoustic vehicle recognition ("Flash Lights and Sound Horn")
The four services with the highest priority are listed in the following table.
| Priority | Service |
|---|---|
| 1 | Automatic emergency call |
| 2 | Manual emergency call |
| 3 | Roadside assistance |
| 4 | MB Info |
MB-Info and breakdown assistance can be converted into a higher priority service by pressing the button of this higher priority service without the voice connection being interrupted. An MB-Info call is converted to a manual emergency call, for example, if the SOS button is pressed during an active MB-Info call.
| Electrical function diagram for status display of emergency call system function | PE82.95-P-2061-97FBA | ||
| Electrical function diagram for manual or automatic emergency call function | PE82.95-P-2066-97FBA | ||
| Electrical function diagram for voice connection between vehicle and Service Center function | PE82.95-P-2069-97FBA | ||
| Electrical function diagram for position finding function | PE82.95-P-2070-97FBA | ||
| Additional telematics services function | GF82.95-P-2025RFU | ||
| Overview of system components, telematics | GF82.85-P-9999RF |