Communications Network: Notes

Vehicle communication utilizes both ISO 9141 and Controller Area Network (CAN) communications. ISO 9141 is used 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 individual control modules that control each function.

The vehicle has 3 module communication networks:

• ISO  9141
• Medium Speed Controller Area Network (MS-CAN)
• High Speed Controller Area Network (HS-CAN)

Both 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 both networks from one connector. The DLC  can be found under the instrument panel.

Network Topology 

Fig 1: Network Topology Communication Diagram

Courtesy of FORD MOTOR CO.