Code 44: O2 Sensor (Lean Fuel Mixture): Notes

The ECM supplies a voltage of about .45 volt between terminals "D6" and "D7". The oxygen sensor varies the voltage from one volt (rich exhaust) to .1 volt (lean exhaust). The sensor acts like an open sensor circuit and produces no voltage when exhaust temperature is less than 600°F (316°C). An open sensor circuit or cold sensor causes "open loop" operation.

NOTE: Test numbers refer to test numbers on diagnostic chart.

A Code 44 is set when the oxygen sensor signal voltage on circuit No. 412 remains less than .2 volt for 50 seconds and system is operating in "closed loop".