Self-Diagnosis Description

The ECM monitor the input/output signals. (Some signals at all times and the others under specified conditions) When the ECM detects an irregularity, the trouble code is to be saved in memory and the output signal sent to the self-diagnosis output terminal.

The diagnosis result is read on Hi-scan.

The diagnostic trouble code (DTC) will remain in the ECM as long as the battery power is maintained.

The diagnostic trouble code will however, be erased when the battery terminal or engine control unit (ECM) connector is disconnected, or erased by the Hi-scan.