Description of On-Board Diagnostics

The ECM monitors the input/output signals (some signals at all times and the others under specified conditions).
When the Engine Control Module (ECM) detects that 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 with Malfunction Indicator Lamp (MIL) or Scan Tool (ST). 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 (ECM) connector is disconnected.

NOTE: If the sensor connector is disconnected with the ignition switch turned on, the (DTC) is memorized. In this case, disconnect the battery negative terminal (-) for 15 seconds or more, and the diagnosis memory will be erased.