Description And Operation: 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 AND OPERATION .
Use of the MIT019 Multi-Media Tester may cause the radio screen to go blank.
The audio system components are designed to provide audio entertainment and information through the reception, tuning and amplification of locally broadcast radio signals in both the Amplitude Modulating (AM) and Frequency Modulating (FM) commercial frequency ranges. If the vehicle is so equipped, the audio system can also receive, amplify or process certain cellular, satellite audio and satellite Global Positioning System (GPS) radio signals. The audio system components operate on battery current received through a fuse in the Body Control Module (BCM).
The optional navigation radio system receives GPS signals from up to eight satellites to display the position and direction of the vehicle. An electronic gyro-sensor and the speed sensor in the vehicle enable the system to display the present vehicle position even in locations where GPS signals may be blocked. When a destination is selected, the navigation system uses information from the map to quickly calculate a route. As the vehicle is driven along the chosen route, the operator is guided with pictorial displays and voice prompts.
On vehicles that are equipped with the optional remote radio switches, the BCM receives the input from the switches on the steering wheel. The programming in the BCM allows it to process those inputs and send the appropriate electronic command messages to the radio receiver over the Controller Area Network - Interior High Speed (CAN-IHS) data bus to control the radio volume up or down, station seek up or down, preset station advance, and mode advance functions.
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 Data Link Connector (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.