HO2S Sensor 1

Scan Tool Displays NOT READY or READY. The HO2S Sensor 1 indicates the status of the fuel control exhaust oxygen sensor. The scan tool indicates that the exhaust oxygen sensors are ready when the PCM detects a fluctuating HO2S voltage sufficient to allow closed loop operation. This will not occur unless the exhaust oxygen sensors are warmed up.

Scan Tool Range 0 to 1132 mV. The scan tool display represents the fuel control exhaust oxygen sensor output voltage. The HO2S voltage should fluctuate constantly within a range between 10 mV (lean exhaust) and 1000 mV (rich exhaust) while operating in Closed Loop.