Information Bus: Description and Operation

Description of the Individual Components
The Powertrain Control Module (PCM) governs all operations in connection with the engine. The PCM is linked to the Data Link Connector (DLC) via the Diagnostic Data Bus (SCP). Data stored in the PCM can be read via the DLC using the NGS diagnostic tester.

The Passive Anti-theft System (PATS) module is on the diagnostic data bus (SCP). The PATS module contains circuitry to connect the vehicle electrical system, the transceiver module, the vehicle module communications network and the vehicle theft indicator. The PATS module uses a microprocessor to control the system functions. The PATS module microprocessor stores the ignition key codes in non-volatile memory. The PATS module can be diagnosed through the data link connector.

The data link connector (DLC) serves as an interface between the modules and the diagnostic tester. This electrical connector is connected to all modules capable of diagnosis via the diagnostic data buses (SCP or 1SO9141).

The ABS module controls the anti-lock braking functions via the brake circuits, and is connected to the DLC via the diagnostic data bus.

The diagnostic data bus (SCP) consists of two lines, that is the 4-PB9 (GY/VT) and the 5-PB9 (BU/WH), along which communication with the diagnostic tester still takes place, even if one of the two lines is broken, has ground contact or a short-circuit to a battery voltage. Should one of these faults occur, this is stored and can be read out. If both lines are damaged, communication with the modules is no longer possible.

The diagnostic data bus (ISO9141) is a one-strand line 8-CF29 (WH/VT), along which communication is no longer possible if the line is broken, has ground contact or a short-circuit to a battery voltage.