Description & Operation

The module communications network provides the ability for module-to-module communication by sharing inputs and outputs instead of each component having an input and output wired directly to each module. Vehicle has 2 module communications networks: the Standard Corporate Protocol (SCP) network and the International Standards Organization (ISO) 9141 network.

The SCP network consists of a pair of twisted wires connected between the Data Link Connector (DLC), Powertrain Control Module (PCM) and instrument cluster. Even if one of the wires is open or shorted, communication is still possible between modules and DLC.

The ISO 9141 network consists of a single wire connected between DLC, Anti-Lock Brake System (ABS) control module, Restraint Control Module (RCM), Central Timer Module (CTM) and Central Security Module (CSM). This article is used to diagnose SCP and ISO 9141 communications network circuit faults. For module locations, see COMPONENT LOCATIONS  .