Circuit Description

The ECM supplies a voltage of about .45 volt between terminals "D6" and "D7" (If measured with a 10-megohms digital voltmeter, this may read as low as .32 volts). The O2 sensor varies voltage from about one volt (rich exhaust), to about .10 volt (lean exhaust).

The sensor is similar to an open circuit when its temperature is below about 600°F (315°C), and it produces no voltage. An open sensor circuit or cold sensor causes open loop operation.