Circuit Description

ECM supplies voltage of about .45 volt between terminals "D7" and "E15". If measured with digital voltmeter with 10 megohm impedance, this may read as low as .32 volts. The oxygen sensor varies voltage within range of about one volt if exhaust gases are rich, down to about .10 volt if exhaust gases are lean. When sensor is below 600°F (315°C), no voltage signal is produced. An open sensor circuit or cold sensor causes "Open Loop" operation.