Code 44 - Lean Oxygen Sensor Value: Notes

About .45 volt is supplied by ECM between terminals "YC14" and "YC15" (if measured with 10 megohm digital voltmeter, reading may be as low as .32 volt). The O2 sensor varies voltage within a range of .10-1 volt (from lean to rich). The O2 sensor operates like an open circuit and produces no voltage when its temperature is below 600°F (316°C). ECM operates in "open loop" until temperature exceeds given value.

1. The following conditions must be met to set a Code 44 when signal voltage is present on circuit No. 412:
   • Value remains below .3 volts for 50 seconds or more.
   • System is operating in "closed loop".
   • No Code 33 or 34.
   • "Closed" loop integrator active.
2. This test checks to see if sensor is at fault for lean indication or if there is an ECM wiring problem.