As activated by power supply, ECM receives signals from several sensors such as Crank Position Sensor, Acceleration Position Sensor. ECM controls engine as actuating injectors, various solenoids and relays by comparing sensor signals with CONTROL LOGIC of micro controller and EEPROM.

For reliability of control, ECM performs SELF TEST and diagnoses several sensors and actuators. If serious errors which have influence on driving performance, ECM notifies drivers and mechanics of malfunction informations. ECM can shut system down to prevent the system from dangerous situation by miss controls.