Description & Operation: Notes

The module communications network is the means which up to 10 separate control modules can communicate with each other to carry out tasks that may require information or action from more than one module. The modules are linked to each other through a twisted wire pair called Data Bus Plus and Data Bus Minus. Data Bus Plus is also identified as circuit No. 914 (+). Data Bus Minus Is also identified as circuit No. 915 (-).

The data bus lines are routed throughout the vehicle to each module as a common "bus" or party line where all modules share information. See Fig 1 . Information on data lines is transmitted in a pulse width type code. Any module can transmit or receive information equally, there is no "master" module. If more than one module attempts to send information at the same time, the message with highest priority is given network access first. This addressing scheme is known as Standard Corporate Protocol (SCP).

Information on data lines can be accessed for trouble shooting (including diagnostic trouble codes) from the Data Link Connector (DLC), using New Generation Star scan tester. If a generic scan tester is used, ensure it has equivalent capabilities.