MFI Control System: Description: Self-Diagnosis

The ECU monitors the input/output signals (some signals at all times and the others under specified conditions). When the ECU detects an irregularity, it memorize the diagnostic trouble code, and outputs the signal to the self-diagnosis output terminal. The diagnosis results can be read out Hi-Scan Tool. Diagnostic trouble code (DTC) will remain in the ECU as long as battery power is maintained. The diagnostic trouble code will, however, be erased when the battery terminal or the engine control unit (ECU) connector is disconnected or erased by Generic Scan Tool.