Circuit Description

The Engine Control Module (ECM) is the control center of the fuel injection system. It constantly looks at the information from various sensors and controls the systems that affect vehicle performance. The ECM also performs the diagnostic function of the system. It can recognize operational problems, alert the driver through the Malfunction Indicator Lamp (MIL) (Check Engine) and store a Diagnostic Trouble Code (DTC) or DTCs which identify the problem areas to aid the technician in making repairs. An Electrically Erasable Programmable Read Only Memory (EEPROM) is used to house the program information and the calibrations required for engine, transmission and powertrain diagnostics operation. The Diagnostic Trouble Code (DTC) will stored, when the ECM detects SPI communication between main CPU and output driver I/C is corrupted.