HO2S 2

The scan tool range is 0-1275 mV: The rear HO2S 2 indicates the oxygen content of the exhaust exiting the catalytic converter. A normal warm HO2S 2 output voltage will be inactive or appear to be lazy. When the engine is operating in Closed Loop, the HO2S 2 voltage will be stable between 100 mV and 900 mV.