F 250 4WD Pickup V6-4.2L VIN 2 (1998)
Information Bus: Description and Operation
The vehicle has two module communications networks. The Standard Corporate Protocol (SCP) which is an unshielded twisted pair cable (data bus plus,
circuit 914 and data bus minus, circuit 915), and the International Standards Organization (ISO) 9141 network which is a single wire (circuit 70 [/W]).
Both networks can be connected to New Generation STAR (NGS) Tester at one connector called the Data Link Connector (DLC). This makes
troubleshooting these systems easier by allowing one smart tester to be able to diagnose and control any module on the two networks from one
connector. The DLC is located under the instrument panel between the steering column and the radio.
The ISO 9141 communication network does not permit inter-module communication. When NGS Tester communicates to modules on the diagnostic
communication network, NGS Tester must ask for all information; the modules cannot initiate communications.
The SCP network will remain operational even with the severing of one of the bus wires. Communications will also continue if one of the bus wires is
shorted to chassis ground or battery positive voltage (B+), or if a termination resistor is lost. This faulted condition is detected and reported to the host
by the module's network bus interface circuits.
