Inspection Using An Oscilloscope (Reference)

Cooling fan control signal 

PCM terminals 

• 1R (+)-body ground (-)

Oscilloscope setting 

• 5 V/DIV (Y), 1 ms/DIV (X), DC range

Vehicle condition 

• Idle after warm up
  Fig 1: Waveform Graph (Cooling Fan Control Signal)

  Courtesy of MAZDA MOTORS CORP.

Purge control signal 

PCM terminals 

• 2C (+)-body ground (-)

Oscilloscope setting 

• 2 V/DIV (Y), 10 ms/DIV (X), DC range

Vehicle condition 

• Idle after warm up
  Fig 2: Waveform Graph (Purge Control Signal)

  Courtesy of MAZDA MOTORS CORP.

APP sensor signal 

Accelerator pedal is released 

Accelerator pedal is depressed 

PCM terminals 

• 1AO (+)-body ground (-)

Oscilloscope setting 

• 2.5 V/DIV (Y), 2 ms/DIV (X), DC range

Vehicle condition 

• Ignition switch is turned to the ON position. (engine off)
  Fig 4: Waveform Graph (APP Sensor Signal)

  Courtesy of MAZDA MOTORS CORP.

OCV signal 

PCM terminals 

• 2E (+)-body ground (-)

Oscilloscope setting 

• 2 V/DIV (Y), 0.8 ms/DIV (X), DC range

Vehicle condition 

• Idle after warm up
  Fig 5: Waveform Graph (OCV Signal)

  Courtesy of MAZDA MOTORS CORP.

CMP signal 

PCM terminals 

• 2S (+)-body ground (-)

Oscilloscope setting 

• 1 V/DIV (Y), 25 ms/DIV (X), DC range

Vehicle condition 

• Idle after warm up
  Fig 6: Waveform Graph (CMP Signal)

  Courtesy of MAZDA MOTORS CORP.

CKP signal 

PCM terminals 

• 2W (+)-body ground (-)

Oscilloscope setting 

• 1 V/DIV (Y), 2.5 ms/DIV (X), DC range

Vehicle condition 

• Idle after warm up
  Fig 7: Waveform Graph (CKP Signal)

  Courtesy of MAZDA MOTORS CORP.

Generator field coil control signal 

PCM terminals 

• 2AA (+)-body ground (-)

Oscilloscope setting 

• 0.5 V/DIV (Y), 2 ms/DIV (X), DC range

Vehicle condition 

• Idle after warm up (engine speed approx. 650 rpm, no load, A/C off)
  Fig 8: Waveform Graph (Generator Field Coil Control Signal)

  Courtesy of MAZDA MOTORS CORP.

Generator output voltage signal 

PCM terminals 

• 2AF (+)-body ground (-)

Oscilloscope setting 

• 2 V/DIV (Y), 1 ms/DIV (X), DC range

Vehicle condition 

• Idle after warm up
  Fig 9: Waveform Graph (Generator Output Voltage Signal)

  Courtesy of MAZDA MOTORS CORP.

IGT1, IGT2, IGT3, IGT4 signals 

PCM terminals 

• IGT1 (No. 1): 2G (+)-body ground (-)
• IGT2 (No. 2): 2K (+)-body ground (-)
• IGT3 (No. 3): 2L (+)-body ground (-)
• IGT4 (No. 4): 2H (+)-body ground (-)

Oscilloscope setting 

• 4 V/DIV (Y), 0.01 ms/DIV (X), DC range

Vehicle condition 

• Idle after warm up
  Fig 10: Waveform Graph (IGT1, IGT2, IGT3, IGT4 Signals)

  Courtesy of MAZDA MOTORS CORP.

Fuel injection signal 

PCM terminals 

• Fuel Injection No. 1: 2BB (+)-body ground (-)
• Fuel Injection No. 2: 2BC (+)-body ground (-)
• Fuel Injection No. 3: 2BD (+)-body ground (-)
• Fuel Injection No. 4: 2AZ (+)-body ground (-)

Oscilloscope setting 

• 4V/DIV (Y), 20 ms/DIV (X), DC range

Vehicle condition 

• Idle after warm up
  Fig 11: Waveform Graph (Fuel Injection Signal)

  Courtesy of MAZDA MOTORS CORP.

A/F sensor heater control signal 

PCM terminals 

• 2A (+)-body ground (-)

Oscilloscope setting 

• 5 V/DIV (Y), 200 ms/DIV (X), DC range

Vehicle condition 

• Idle after warm up (engine speed approx. 650 rpm, no load, A/C off)
  Fig 12: Waveform Graph (Front HO2S Heater Control Signal)

  Courtesy of MAZDA MOTORS CORP.

HO2S heater control signal 

PCM terminals 

• 2B (+)-body ground (-)

Oscilloscope setting 

• 5 V/DIV (Y), 1 s/DIV (X), DC range

Vehicle condition 

• Idle after warm up (engine speed approx. 650 rpm, no load, A/C off)
  Fig 13: Waveform Graph (Rear HO2S Heater Control Signal)

  Courtesy of MAZDA MOTORS CORP.