Self Diagnosis

SELF-DIAGNOSIS
The ECM monitors the input/output signals (some signals at all times and the others under specified conditions). When the ECM detects that an irregularity, it memorizes the diagnostic trouble code, and outputs the signal to the self-diagnosis output terminal. The diagnosis results can be read out with MIL (only for TYPE 1) or HI-SCAN. Diagnostic trouble code (DTC) will remain in the ECM as long as battery power is maintained. The diagnostic trouble code will, however, be erased when the battery terminal or the engine control module (ECM) connector is disconnected.

NOTE
1. If the sensor connector is disconnected with the ignition switch turned on, the diagnostic trouble code (DTC) is memorized. In this case, disconnect the battery negative terminal (-) for 15 seconds or more, and the diagnosis memory will be erased.
2. When battery voltage is low, diagnostic trouble codes can not be read. Be sure to check the battery voltage and other conditions before starting the test.
3. Diagnosis memory is erased if the battery or the ECM connector is disconnected. Do not disconnect the battery before the diagnostic trouble codes are completely read and recorded.