Self-Diagnostic System: Notes

The Engine Control Module (ECM) monitors the input/output signals (some signals at all times and others under specified conditions). When the ECM detects an irregularity, it memorizes the Diagnostic Trouble Code (DTC) and sets the Malfunction Indicator Light (MIL). The ECM also outputs the signal to the self-diagnosis output terminal. The diagnosis results can be read by a Hi-Scan Pro or Generic Scan Tool. A DTC will remain in the ECM memory as long as battery power is maintained. The DTC will be erased when the battery terminal or the ECM connector is disconnected, or by using the Hi-Scan Pro or Generic Scan Tool.