HO2S Sensor 1

Scan tool displays READY or NOT READY. Indicates the status of the exhaust oxygen sensor. The scan tool will indicate that the exhaust oxygen sensor is ready when the PCM detects a fluctuating HO2S voltage sufficient in order to allow Closed Loop operation. This will not occur unless the exhaust oxygen sensor is warmed up.

Scan tool displays 0-111 mV. Indicates the exhaust oxygen sensor output voltage. While operating in Closed Loop, the voltage should constantly fluctuate from 10 mV, indicating a lean exhaust, to 1000 mV.