Description & Operation

NOTE: 2WD vehicles without power windows and/or power door locks are equipped with a Central Timer Module (CTM). All other vehicles are equipped with a Generic Electronic Module (GEM).

Vehicle has 2 module communications networks. The Powertrain Control Module (PCM) is connected to the multiplex communications network through a pair of twisted wires or BUS. The BUS network is also referred to as Standard Corporate Protocol (SCP). The BUS consists of a positive (+) circuit and negative (-) circuit (circuit No. 914 and 915 respectively).

The air bag diagnostic monitor and all other optional modules, the Generic Electronic Module (GEM), Remote Anti-Theft Personality (RAP) module and 4-Wheel Anti-Lock Brake System (4WABS) module, are connected to the International Standards Organization (ISO) 9141 diagnostic communications network through a single wire (circuit No. 70). Both networks are connected to the Data Link Connector (DLC). This article is used to diagnose BUS and ISO communications network circuit faults. For module locations, see COMPONENT LOCATIONS table.