Heated Oxygen Sensor (HO2S): Troubleshooting: Waveform
If you release the accelerator pedal suddenly after engine running about 4000 RPM, fuel supply will stop for short period and the O2 sensor service data in the Hi-Scan (Pro) will display values 200 mV or lower. When you suddenly press on the accelerator pedal down, the voltage will reach 0.6 ~ 1.0 V.
When you let the engine idle again, the voltage will fluctuate between 200 mV or lower and 0.6 ~ 1.0 V.
In this case, the O2 sensor can be determined as good.