F 350 2WD Super Duty V10-6.8L (2009)
Information Bus: Description and Operation
Communications Network
NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).
Vehicle communication utilizes both ISO 9141 and Controller Area Network (CAN) communications. ISO 9141 is for diagnostic use only, and CAN is
used for many modules to communicate with each other on a common network. CAN in-vehicle networking, is a method for transferring data among
distributed electronic modules via a serial data bus. Without serial networking, intermodule communication requires dedicated, point to point wiring
resulting in bulky, expensive, complex, and difficult to install wiring harnesses. Applying a serial data network reduces the number of wires, combining
the signals on a single network. Information is sent to the individual control modules that control each function.
The vehicle has 3 module communication networks:
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ISO 9141
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Medium Speed Controller Area Network (MS-CAN)
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High Speed Controller Area Network (HS-CAN)
All 3 networks are connected to the Data Link Connector (DLC). This makes diagnosis and testing of these systems easier by allowing one scan tool to
be able to diagnose and control any module on the 3 networks from one connector. The DLC can be found under the instrument panel between the
steering column and the Audio Control Module (ACM).
Network Topology
