Circuit Description

The engine control module (ECM) is the control center of the fuel injector 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 lamp indicator (MIL), and store a 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 ECM monitors EEPROM reset flag and lower power counter I/C overflow bits. If the ECM detects if lower power counter I/C has been reset due to battery disconnect or lower power counter I/C malfunction, the DTC will be stored.