Module, Emergency Assistance (EAM): Operation
The Security Gateway Module (SGW) is the Controller Area Network (CAN) gateway between the radio, telematics modules, Data Link Connector (DLC) and the other vehicle CAN modules. An SGW failure could prevent the radio from powering up, telematics module from communicating or a scan tool from communicating with the vehicle. For additional information on the SGW. Refer to MODULE, SECURITY GATEWAY (SGW), DESCRIPTION .
The Emergency Assistance Module (EAM) system will detect an audio emergency call (eCall) trigger, whether automatic through a crash severe enough or manual at a vehicle occupant's request by pressing the SOS button. Once triggered, the system will attempt to send a Minimum Set of Data (MSD) to any public system operated by a Mobile Network Operator (MNO) and also attempt to establish a voice connection between the vehicle and the Public Safety Answering Point (PSAP). When connected to the MNO, the vehicle will transfer the vehicle location and Vehicle Identification Number (VIN).
The EAM system is triggered automatically when the Occupant Restraint Controller (ORC) sends a signal using the CAN - Chassis (CAN-C) data bus or the Output Digital Serial line. The severity of the crash will determine if an eCall is sent or not. This will include direction of the impact, whether frontal, side, rear or rollover.
The EAM system can be manually triggered using the SOS button by the vehicle driver or a passenger. The EAM will actuate the system in the same manner as if it had been triggered automatically by the ORC. When eCall is in operation, the radio audio will be muted and eCall audio will be heard through the eCall speaker.
In the event that the vehicle battery connection is compromised, a backup battery is mounted within the EAM to ensure the integrity of the system and a continuation of an eCall if the vehicle battery becomes disconnected while a call is in progress. If the backup battery becomes discharged, a message will be indicated in the Instrument Panel Cluster (IPC) and a diagnostic code set in the EAM.
The EAM microcontroller continuously monitors all of the EAM system electrical circuits to determine the system readiness. If the EAM detects a monitored system fault, it sets an active and stored Diagnostic Trouble Code (DTC) and sends electronic messages to the IPC and Body Control Module (BCM) over the CAN data bus to turn ON the EAM indicator. An active fault only remains for the duration of the fault, or in some cases for the duration of the current ignition cycle, while a stored fault causes a DTC to be stored in memory by the EAM.
The SGW is in the audio and telematics systems to provide security against certain types of attacks and threats from the scan tool, telematics and entertainment buses, which can put the rest of the vehicle's buses at risk of intrusion. The SGW lies electrically between the vehicle on one side, and the DLC, telematics and entertainment systems on the other side. The main function is to gate messages from one bus to another. The SGW monitors the B+ Feed, switched ignition feed, CAN circuits, software and hardware for any concerns.