Diagnostic System
ECM of EFC system is equipped with a self-diagnostic function. When trouble occurs, ECS (Electronic Control System) light is illuminated and the trouble code is displayed on O2 monitor light. See Fig 1 .
To read trouble codes, observe oxygen sensor monitor light. This light has 2 duration periods of illumination, one period long (1.2 seconds) and one period short (.3 seconds). The long period signifies the tens digit in a numbered code. Short period signifies the ones digit. Example: 3 long flashes and 5 short flashes, would signify a code 35.
It is possible to have more than one code present. In this case, the lowest number trouble code should be diagnosed first, the next highest numbered code second and so on (sequentially). Trouble codes will be repeated as long as the system is in diagnostic mode.