Additional functions of the CMDC are self-diagnosis, control of the maximum permissible engine speed, adsorber purge control, activation of the fuel pump and heating of the oxygen content sensor in the exhaust gas, control of the battery voltage, communication with other systems, such as - ABS-ASC + T or EDC; AGS; RDC; ride height regulator; rain intensity sensor; passive heat accumulator; airbags and a number of other systems.
The self-diagnosis system detects malfunctions in the operation of the ECU-KSUD and enters them into memory in the form of codes. In the event of a malfunction of the coolant temperature sensors, air temperature, air flow measurement sensor, the system switches to work according to the average values included in the engine control program. Reading the codes at the workshop allows you to quickly identify the cause of the malfunction and eliminate it. As soon as the engine shaft speed reaches the maximum value, on command from the ECU-KSUD, the fuel supply to the engine cylinders is interrupted by turning off the injectors.
Fuel vapors cannot leave the fuel tank without bypassing the adsorber. The fuel tank vent solenoid valve is controlled according to the condition of the engine. The gasoline vapors formed in the fuel tank are accumulated in the adsorber and are fed through the solenoid valve into the combustion chamber and burned. The adsorber purge valve operates cyclically and is controlled by the ECU-KSUD depending on the engine operating mode. While the valve is energized (more than 10 V), the piping to the inlet piping is closed. When the voltage is removed from the valve, it can open under the influence of vacuum in the intake manifold.
The fuel pump is turned on through a relay that closes its contacts on a signal from the ECU-KSUD when the starter starts to scroll the engine shaft.
To communicate with other control units, the ECU-KSUD has a special data bus for exchanging information between systems. Such a bus provides high efficiency and a degree of vehicle protection in case of failure of individual devices, and also reduces the number of conductors in the cable harness.