Code P013, Rear Heated Oxygen Sensor Not Ready: Notes

PCM provides .45-volt reference signal to oxygen sensor on circuit No. 1670. When oxygen sensor reaches operating temperature, it will generate a counter voltage that will vary based on amount of oxygen in exhaust. Rear oxygen sensor is located in manifold, before catalytic converter.

A lean exhaust will generate a low voltage and cause .45-volt reference signal to decrease. A rich exhaust will generate a higher voltage and cause .45-volt reference signal to increase. Code P013 will set when oxygen sensor cannot respond under test conditions and generate a voltage greater or less than .45-volt reference.