F 150 2WD Pickup V8-4.6L CNG SOHC VIN 9 (1997)
The diagnostic communication network does not permit inter-module communication. When the NGS communicates to modules on the diagnostic
communication network, the NGS must ask for all information; the modules cannot initiate communications.
Fault Tolerance of the SCP
The SCP 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.
Fault Tolerance of the Diagnostic Communications Network
Unlike the SCP, the ISO 9141 Link will not function if the wire is shorted to chassis ground or battery positive voltage (B+). Also, if one of the modules
on the diagnostic communication network loses power or shorts internally, communications to that module will fail.
Module Description
The Powertrain Control Module (PCM) is on the multiplex communication network. The PCM controls the engine for better fuel economy, emissions
control, and failure mode detection and storage.
The Integrated Air Bag Module (IABM) is on the diagnostic communication network. The IABM controls the deployment of the air bags based on
sensor input.
The Generic Electronic Module (GEM) is on the diagnostic communication network. The GEM controls a variety of systems:
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Windshield wipers.
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Courtesy lamps.
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4-wheel shift on the fly.
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One touch down power windows, etc.
The Remote Anti-theft Personality (RAP) is on the diagnostic communication network. The RAP module controls the anti-theft and keyless remote entry
of the vehicle.
The 4-wheel Anti-lock Brake System (4WABS) is on the diagnostic communication network. The 4WABS controls the brake pressure to the four wheels
to keep the vehicle under control while braking.
