Explains the O2 or Oxygen sensor scanner parameter as used on the modern Scan-1 Diagnostic System. This video goes in depth on reading a O2-Sensor waveform of the oscilloscope or scope, what the frequency should be and amplitude values. If all these factors are not taken into consideration, a false O2-sensor replacement will result. The O2 sensor generates its own signal voltage, which is used by the ECM to cirrect fuel mixture.