F 250 4WD LD Pickup V8-5.4L SOHC VIN L (1997)
Information Bus: Description and Operation
The vehicle has two module communications networks.
The Powertrain Control Module (PCM) is connected with unshielded twisted pair cable (Data Bus Plus, circuit 914 [T/O] and Data Bus Minus, circuit
915 [P/LB]), using the Standard Corporate Protocol (SCP) which allows two or more signals being sent over one circuit.
The Integrated Air Bag Module (IABM) and any of the optional modules are connected to the ISO 9141 Link via a single wire (circuit 70 [LB/W]).
Both networks can be connected to the New Generation STAR (NGS) tester or other compatible scan tool 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 can be found under the instrument panel between the steering column and the radio.