| Description and Operation Module communication is effected via two different data bus systems, in which the data link connector (DLC) forms the interface between the modules and the diagnostic tester. For vehicles with 2.0l DOHC and 2.3l DOHC engines, an additional third data bus system is used. The Controller-Area-Network (CAN) data bus consists of two twisted wires. Communication takes place both between the modules themselves and between the modules and the diagnostic tester, via these lines. If there is a break in one of the lines or a short to ground or short to battery positive is present, then communication between the modules and the diagnostic tester is no longer possible. The International Organisation for Standardisation (ISO) 9141 data bus consists of a single line. If there is a break in the line or a short to ground or short to battery positive is present, then communication between the modules and the diagnostic tester is no longer possible. The Standard Corporate Protocol (SCP) data bus is not installed in all vehicle versions. It is only used in vehicles with 2,0l DOHC and 2.3l DOHC engines. It is only responsible for communication between the PCM and the diagnostic tester. It consists of two twisted wires. If there is a break in one of the lines or a short to ground or short to battery positive is present, then communication between the PCM and the diagnostic tester is no longer possible. The data link connector (DLC) is a standard 16-pin connector, which connects the communication lines (CAN, SCP and ISO 9141), the EEPROM programming line and the diagnostic tester power supply. The steering position sensor transmits the turning angle of the steering wheel to the Electronic Stability Program (ESP) module and communicates with the ESP module and the DLC via the CAN data bus. The vehicle is fitted with either the ESP module or the ABS module (with or without TCS). The ESP module controls the anti-lock braking system (ABS), the traction control system (TCS) and the stabilising system. It is connected to the PCM, the steering position sensor and the DLC via the CAN data bus. There is also a connection to the DLC via the ISO data bus. The ABS module with TCS controls the anti-lock braking system and the traction control system and is connected to the PCM and the DLC via the CAN data bus. There is also a connection to the DLC via the ISO data bus. The PCM controls all functions related to engine management and emission control. This module communicates with the ESP module, the ABS module with TCS, the instrument cluster and the DLC via the CAN data bus. The instrument cluster is connected to the DLC and the PCM via the CAN data bus. If the vehicle is equipped with a diesel engine, a fuel-fired booster heater is fitted. This supplements the interior heating at low ambient temperatures. The airbag module controls the driver's and passenger's airbags, the side airbags and the pyrotechnic seat belt pretensioner. The module is connected to the DLC via the ISO data bus. The Generic Electronic Module (GEM) is connected to the DLC via the ISO data bus and controls all time-dependent functions. The PCM transmits the engine speed signal for the tachometer, the engine temperature signal for the coolant temperature display and the signal for the speedometer to the instrument cluster, via the CAN data bus. | 