Inspection Using An Oscilloscope (Reference)

Throttle control (+) signal 

PCM terminals 

• 2A (+)-Negative battery terminal (-)

Oscilloscope setting 

• 5 V/DIV (Y), 1 ms/DIV (X), DC range

Vehicle condition 

• Idle (Accelerator pedal released)

Throttle control (-) signal 

PCM terminals 

• 2B (+)-Negative battery terminal (-)

Oscilloscope setting 

• 5 V/DIV (Y), 1 ms/DIV (X), DC range

Vehicle condition 

• Idle (Accelerator pedal released)
  Fig 2: Screen Display - Throttle Control (-) Signal Waveform

  Courtesy of MAZDA MOTORS CORP.

Purge control signal 

PCM terminals 

• 2C (+)-Negative battery terminal (-)

Oscilloscope setting 

• 2 V/DIV (Y), 0.1 s/DIV (X), DC range

Vehicle condition 

• Idle after warm-up
  Fig 3: Screen Display - Purge Control Signal Waveform

  Courtesy of MAZDA MOTORS CORP.

OCV control signal 

PCM terminals 

• 2E (+)-Negative battery terminal (-)

Oscilloscope setting 

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

Vehicle condition 

• Idle after warm-up
  Fig 4: Screen Display - OCV Signal Waveform

  Courtesy of MAZDA MOTORS CORP.

CMP signal 

PCM terminals 

• 2S (+)-Negative battery terminal (-}

Oscilloscope setting 

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

Vehicle condition 

• Idle after warm-up

CKP signal 

PCM terminals 

• 2W (+)-Negative battery terminal (-)

Oscilloscope setting 

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

Vehicle condition 

• Idle after warm-up
  Fig 6: Screen Display - CKP Signal Waveform

  Courtesy of MAZDA MOTORS CORP.

Generator field coil control signal 

PCM terminals 

• 2AI (+)-Negative battery terminal (-)

Oscilloscope setting 

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

Vehicle condition 

• Idle after warm-up
  Fig 7: Screen Display - Generator Field Coil Control Signal Waveform

  Courtesy of MAZDA MOTORS CORP.

Generator output voltage signal 

PCM terminals 

• 2AJ (+)-Negative battery terminal (-)

Oscilloscope setting 

• 2 V/DIV (Y), 1 ms/DIV (X), DC range

Vehicle condition 

• Idle after warm-up
  Fig 8: Screen Display - Generator Output Voltage Signal Waveform

  Courtesy of MAZDA MOTORS CORP.

Ignition timing signals 

PCM terminals 

• IGT1 (No. 1):2BA(+)-Negative battery terminal (-)
• IGT2 (No. 2): 2AW (+)-Negative battery terminal (-)
• IGT3 (No. 3): 2AX (+)-Negative battery terminal (-)
• IGT4 (No. 4): 2AT (+)-Negative battery terminal (-)

Oscilloscope setting 

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

Vehicle condition 

• Idle after warm-up

Fuel injection signals 

PCM terminals 

• Fuel Injection No. 1: 2BB (+)-Negative battery terminal (-)
• Fuel Injection No. 2: 2BC (+)-Negative battery terminal (-)
• Fuel Injection No. 3: 2BD (+)-Negative battery terminal (-)
• Fuel Injection No. 4: 2AZ (+)-Negative battery terminal (-)

Oscilloscope setting 

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

Vehicle condition 

• Idle after warm-up
  Fig 10: Screen Display - Fuel Injection Signal Waveform

  Courtesy of MAZDA MOTORS CORP.

A/F sensor heater control signal 

PCM terminals 

• 2BG (+)-Negative battery terminal (-)

Oscilloscope setting 

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

Vehicle condition 

• Idle after warm-up (no load)
  Fig 11: Screen Display - A/F Sensor Heater Control Signal Waveform

  Courtesy of MAZDA MOTORS CORP.