Communication network (vehicles after 08.2001)

Modules

• Powertrain control module (PCM)
• General electronic module (GEM)
• Dashboard
• Auxiliary instrument panel
• ABS Module/Electronic Stability Program Module (ESP)
• Airbag Diagnostic Monitor.
• Trip computer module
• Electronic automatic temperature control module (EATC)
• Additional heater
• Xenon headlight control module/headlight range correction sensor
• Nozzle control module (IDM)
• Data link connector (DLC)
• Xenon headlight diagnostic connector

Network elements

The communication network between modules in this vehicle uses three different types of communication buses, which can be divided into buses for communication purposes and buses for diagnostic purposes. Communication network between modules allows you to control various functions (ABS, engine management, airbag control, etc.), and the diagnostic network speeds up the troubleshooting process.

• SCP Bus (Standard Corporate Protocol) consists of two twisted wires (lines). Communication over these lines occurs both between the modules themselves and between the modules and the diagnostic tester. Even in the event of a break in one of the lines, a short circuit to "mass" or a short circuit to the electrical power circuit, communication between the modules and the diagnostic tester is maintained, provided by another line.
• The K-line ISO 9141 bus is a single line. In the event of a break, short circuit to "mass" or a short circuit to the power supply circuit, communication between the module and the diagnostic tester is not possible.
• CAN bus (Controller Area Network) provides communication of modules with each other and, accordingly, via DLC with a diagnostic tester. This serial data bus is designed for use in vehicles and ensures communication even if one of the modules fails.

Data link plug (DLC) is a standard bus-to-bus communication interface (SCP, ISO and CAN) and diagnostic tester. The EEPROM programming signal and power supply for the diagnostic tester also takes place through this 16-pin male connector.


The xenon headlight diagnostic connector is installed at the front of the vehicle and allows, using a diagnostic tester, basic adjustment of the xenon headlights while visually observing both headlights. The xenon headlight diagnostic connector is connected to the DLC via the K-Line ISO 9141 bus.

Modules:

Powertrain control module (PCM) controls all functions related to engine management and exhaust system. This module communicates with the ESP module, ABS module, instrument panel, sub-instrument panel, EATC and DLC via the SCP bus or with the injector control module (IDM) via the CAN bus.

GEM module (common electronic module) connects to data link connector (DLC) via the K-Line ISO 9141 bus and is responsible for the following functions:

• Direction indicators.
• Hazard warning
• Interior lighting
• Anti-theft system
• Central locking
• Heated windshield
• Rear window heating
• Wiper/Washer Controls
• Energy saving relay
• Seat belt warnings
• shock sensor
• Light on warning

The instrument panel is connected to the data link connector (DLC) via the SCP bus and includes the following functions:

• Speedometer
• Tachometer
• Odometer
• Odometer
• Fuel gauge
• Engine temperature gauge
• Indicators and control lamps

The auxiliary instrument panel is connected to the data link connector (DLC) via the SCP bus and includes the following control functions:

• Oil temperature
• Oil pressure
• Ice Warning Warning Light

The vehicle is equipped with either an ABS module (with or without TCS) or an electronic course stability program module (ESP).

• The ABS module without TCS controls the anti-lock brake system and has different software than the ABS module with TCS, but is otherwise identical. The ABS module communicates with the DLC via K-Line ISO 9141 and SCP buses.
• The ABS module with TCS controls the anti-lock brake system and traction control and communicates with the DLC via K-Line ISO 9141 and SCP tires.
• ESP module in addition to anti-lock braking system (ABS) and traction control (TCS) controls the course stability control system. The ESP module communicates with the DLC via K-Line ISO 9141 and SCP buses.

The airbag diagnostic monitor controls the driver and passenger airbags, side airbags, and pyrotechnic seat belt pretensioners. The airbag diagnostic monitor module communicates with the DLC via the ISO 9141 diagnostic data bus.

The trip computer module communicates with the DLC via the ISO 9141 diagnostic data bus. The trip computer provides the driver with additional information about the state of the car and, accordingly, about the environment, and includes the following functions:

• Fuel consumption
• Time Information
• Distance measurement
• Outdoor temperature display

The EATC module communicates with the DLC via SCP and K-Line ISO 9141 buses. The main function of this module is to automatically control the temperature in the A/C system by controlling air flow, air distribution and air temperature. The EATC module controls the following subsystems and includes some additional switches.

• A/C switch
• Air distribution switch
• Recirculation damper switch
• Electric fan controller
• Heated windshield switch
• Heated rear window switch

The auxiliary heater is a fuel-fired heating system that heats the coolant in the diesel engine cooling system at low outside temperatures. The auxiliary heater communicates with the DLC via the ISO 9141 diagnostic data bus.


The xenon headlight control module/headlight range sensor is responsible for automatically adjusting the xenon headlights based on vehicle load and speed. The speed signal comes from the PCM and the load condition is determined by two sensors installed one on each axle. In addition to this function, the module works as a DC/DC converter that supplies the sensors with a constant 5V power supply. The xenon headlight control module/headlight range sensor is connected to the DLC and the xenon headlight diagnostic connector via the ISO 9141 diagnostic data bus.

Nozzle control module (IDM) responsible for controlled fuel injection, it communicates with the PCM via the CAN data bus.

Operating principle

Communication between the diagnostic system tester and the modules takes place via two different data buses:

Data bus (SCP)

• Powertrain control module (PCM)
• Dashboard

Data bus (ISO 9141)

• ABS Module / Electronic Stability Program Module (ESP) (Steering wheel position sensor communicates with the electronic stability program module (ESP) via data bus (SCP)). Diagnosis is performed via the electronic stability program module (ESP) and then via the data bus (ISO 9141).
• Central timer module (CTM)
• Anti-theft alarm/double door lock module
• Trip computer module
• Radio/traffic communication module
• Airbag module
• Additional heater