Mustang GT V8-4.6L SOHC VIN X (1998)
Multiplex Communication Network: Description and Operation
The standard corporate protocol (SCP) communication network provides:
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the ability for module-to-module communication by sharing required inputs and outputs instead of each component having an input or output
wired directly to or from each affected module.
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a common link for communication to an off-board tester through the data link connector (DLC) located under the instrument panel to the right of
the steering column.
Two micro-processor based subsystems are included on this network:
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powertrain control
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passive anti-theft
The communication link (or bus) between these subsystems and the DLC consist of an unshielded twisted pair of wires:
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Circuit 914 T/O Bus+
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Circuit 915 PK/LB Bus-
Fault Tolerance
The SCP communication network will remain operational in the event:
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one circuit is severed.
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one circuit is shorted to ground.
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one circuit is shorted to battery positive voltage (B+).
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a termination resistor is lost within a module.
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one or more modules fail internally.
Any of these conditions will be detected and reported to the off-board tester during diagnostics in the form of fault codes.
Purpose
The information given is designed to diagnose SCP communication network concerns. These concerns may:
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affect normal functional operations of the vehicle.
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be directly related to customer concerns.
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be undetectable except during diagnostics.
To properly diagnose a network concern, follow the diagnostic procedure in the order presented.
