The module communications network consists of the following
- anti-lock brake system (ABS) module
- instrument cluster
- powertrain control module (PCM)
- restraint control module (RCM)
- vehicle security module
Refer to SYSTEM WIRING DIAGRAMS for schematic and connector information.
SPECIAL TOOLS 73III Automotive Meter 105-R0057 or equivalent Worldwide Diagnostic System (WDS) Vehicle Communication Module (VCM) with appropriate adapters, or equivalent diagnostic tool
Scheme 1
Scheme 2
Principles of Operation
The vehicle has 2 module communications network protocols
- International Standards Organization (ISO) 9141 communications network
- controller area network (CAN)
The ISO 9141 communications network is a single wire communications network circuit 70 (LB/WH). The CAN is an unshielded, twisted pair cable communications network, circuit 1827 (WH/LG) and circuit 1828 (PK/LG). Both communications networks are connected to the data link connector (DLC). This makes diagnosis and testing of these systems easier by allowing one diagnostic tool to be able to diagnose and control any module on the communications networks from one connector. The DLC can be found under the instrument panel and the steering column.
The ISO 9141 communications network does not permit intermodule communication. When the diagnostic tool communicates to modules on the ISO 9141 communications network, the diagnostic tool must ask for all information; the modules cannot initiate communications. The ISO 9141 communications network does not function if the circuit is shorted to ground or battery voltage. Also, if one of the modules on the ISO 9141 communications network loses power or shorts internally, communications to that module fail.
Anti-Lock Brake System (ABS)
Module The ABS module is on the ISO 9141 communications network. The ABS module controls the brake pressure to the 4 wheels to keep the vehicle under control while braking. The ISO 9141 communications network does not function if the circuit is shorted to ground or battery voltage. Check the communications network circuit 70 (LB/WH) between the ABS module C135 and the DLC C251. The total resistance value must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the ISO 9141 communications network, damage to the DLC C251, damage to the ABS module C135, or a problem in the in-line connector. For additional information, refer to ANTI-LOCK CONTROL .