E 450 V8-5.4L (2009)
Information Bus: Description and Operation
Communications Network
NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).
Module communication utilizes the Medium Speed (MS) and High Speed (HS) Controller Area Network (CAN). Information is sent to and from
individual control modules that each control specific functions. 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 the networks from one connector. The
DLC can be found under the instrument panel between the steering column and the Audio Control Module (ACM).
The module communication networks are:
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Medium Speed Controller Area Network (MS-CAN)
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High Speed Controller Area Network (HS-CAN)
Network Topology
Medium Speed Controller Area Network (MS-CAN) Operation
The MS-CAN communicates using bussed messages. The MS-CAN has an unshielded twisted pair cable, data bus (+) and data bus (-) circuits. In
addition to scan tool communication, this network allows sharing of information between all modules on the network.
The MS-CAN is a medium speed communication network used for the following modules:
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ACM (if equipped)
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IC
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In-dash computer (if equipped)
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PAM (if equipped)
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SJB