Description

DESCRIPTION

The primary on-board communication network between microprocessor-based electronic control modules in this vehicle is the DaimlerChrysler Programmable Communication Interface (PCI) data bus system. However, some modules in the vehicle use the Controller Area Network (CAN-C) data bus system in combination with the PCI bus to form a hybrid bus system. A data bus network minimizes redundant wiring connections; and, at the same time, reduces wire harness complexity, sensor current loads and controller hardware by allowing each sensing device to be connected to only one module (also referred to as a node). Each node reads, then broadcasts its sensor data over the bus for use by all other nodes requiring that data. Each node ignores the messages on the bus that it cannot use.

The hybrid bus system has a central gateway or hub integral to a Body Control Module/Central GateWay (BCMCGW) that is connected to both buses. The gateway physically and electrically isolates the buses from each other and coordinates the bi-directional transfer of messages between them. The BCM is located on the Junction Block (JB), which is located on the driver side instrument panel end bracket in the passenger compartment of the vehicle.

The PCI bus is a single-wire multiplex system, while the CAN-C bus is a two-wire multiplex system. Multiplexing is any system that enables the transmission of multiple messages over a single channel or circuit. Depending upon the optional equipment in the vehicle, the PCI bus is used for communication between most all body interior nodes, while the CAN-C bus is used exclusively by certain powertrain and chassis nodes in vehicles equipped with the hybrid bus.

In addition, certain vehicles may also be equipped with a Serial Controller Interface (SCI) or a K-Line serial link bus to provide direct diagnostic access between a diagnostic scan tool connected to the industry-standard 16-way Data Link Connector (DLC) located below the driver side instrument panel and certain powertrain nodes. The Bus Connections table identifies those nodes in this vehicle with more than one possible bus connection configuration. Those nodes that are not listed in the table are all connected to and accessed through the PCI bus.