Code 44 - Lean Exhaust Indication: Notes

The ECM supplies a voltage of about .45 volt between circuits No. 412 and 413. If measured with a 10-megohm digital voltmeter, this may read as low as .32 volt. The oxygen sensor varies the voltage within a range of about one volt if the exhaust is rich, down to about .10 volt if exhaust is lean. The sensor is like an open circuit and produces no voltage when it is less than about 600°F (360°C). An open sensor circuit or cold sensor causes "open loop" operation.

1. Code 44 is set when the oxygen sensor signal voltage on circuit No. 412 remains less than .2 volt for at least 60 seconds and the system is operating in "closed loop".