Code 45 - Rich Exhaust Indication: Notes

The ECM supplies a voltage of about .45 volt between circuits No 412 and 413. 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 oxygen 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 45 is set when the oxygen sensor signal voltage on circuit No. 412 remains greater than .7 volt for 30 seconds, in "closed loop", engine time after start is one minute or more and throttle angle is greater than 2 percent.