F 250 4WD Pickup V8-5.4L SOHC VIN L (1999)
Information Bus: Description and Operation
Module Communication Network
Principles of 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 [TN/OG] and data bus minus, Circuit 915 [PK/LB]), and the International Standards Organization (ISO) 9141 network which is a single wire
(Circuit 70 [LB/WH]). The New Generation STAR (NGS) Tester can connect to both networks through the Data Link Connector (DLC). This makes
diagnosis and testing of 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 can be found under the instrument panel between the steering column and the radio.
The ISO 9141 communication network does not permit inter-module communication. When the NGS Tester communicates to modules on the ISO 9141
communication network, the NGS Tester must ask for all information; the modules cannot initiate communications.
