Code 45 - O2 Sensor (Rich Fuel Mixture): Notes

The ECM supplies a voltage of approximately .45 volt between terminals D6 and D7. Oxygen sensor varies 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 number refers to test number on diagnostic chart.

A Code 45 is set when oxygen sensor signal voltage or circuit No. D7 remains greater than .7 volt for 50 seconds while in closed loop, engine has been running at least one minute, and throttle angle is greater than 2 percent (about .2 volt more than idle voltage) but less than 25 percent.