A/F sensor heater control signal

PCM terminals 

• 1 BY(+)-body ground(-)

Oscilloscope setting 

• 5 V/DIV (Y), 50 ms/DIV (X), DC range

Vehicle condition 

• Idle after warm up
  Fig 1: A/F Sensor Heater Control Signal Waveform

  Courtesy of MAZDA MOTORS CORP.