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Description & Operation

WARNING: This page is about a different car, the 1997 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.

The module communications network provides the ability for a module-to-module communication by sharing inputs and outputs instead of each component having an input and output wired directly to each module. A BUS which consists of a pair of twisted wires is used to transfer information between each module. The BUS consists of a (+) circuit No. 914 and a (-) circuit No. 915. The BUS is routed throughout the vehicle to Powertrain Control Module (PCM) and Electronic Automatic Temperature Control (EATC) module. See Fig 1. Terminal No. 7 (Light Blue/White wire) on DLC is routed through vehicle to Lighting Control Module (LCM), Anti-Lock Brake System (ABS) Module, Air Bag Diagnostic Monitor, Driver's Door Module (DDM), and Driver's Seat Module (DSM). See Fig 2. This wire is referred to as the ISO 9141 communication link circuit No. 70 and provides a means for the scan tester to communicate with these modules using the DLC. For module locations, see COMPONENT LOCATIONS TABLE. In the event that a system failure exists, a Diagnostic Trouble Code (DTC) will be stored in the module. A New Generation Star (NGS) scan tester and Data Link Connector (DLC) may be used for retrieving and clearing DTCs from the module. DTC may be used for system diagnosis.

COMPONENT LOCATIONS

Component Location
Air Bag Diagnostic Monitor Behind Right Side Of Instrument Panel Cowl Trim Panel
Anti-Lock Brake System (ABS) Control Module Left Front Of Engine Compartment, On Front Of Upper Radiator Support
Data Link Connector (DLC) Below Driver's Side Of Instrument Panel, To Right Of Steering Column
Driver's Door Module (DDM) Inside Driver's Door
Driver's Seat Module Under Driver's Seat
Electronic Automatic Temperature Control (EATC) Module On A/C Evaporator Core Housing At Passenger's Side Of Vehicle
Powertrain Control Module (PCM) In Engine Compartment On Driver's Side Of Safety Wall
Lighting Control Module (LCM) Behind Driver's Side Of Instrument Panel, To Right Of Steering Column
Fig 1: J1850 Module Communication Network Component Locations
G97D28657Courtesy of FORD MOTOR CO.
Fig 2: ISO 9141 Communication Link Component Locations
G97E28658Courtesy of FORD MOTOR CO.