Fault Detection and Trouble Code Memory Function

The engine control module monitors the input/output signals (some signals at all times and the others under specified conditions). When the engine control module detects that an irregularity occurs it will memorize the diagnostic trouble code, and outputs the signal to the self diagnosis output terminal.
There are 14 diagnosis items, including the normal state, and the diagnosis results can be read out with voltmeter or Scan Tool.
Diagnostic trouble code will remain in the engine control module as long as battery power is maintained. The diagnostic trouble code will, however, be erased when the battery terminal or the engine control module connector is disconnected

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