Inspection Using An Oscilloscope (Reference)

Cooling fan control 

PCM terminals 

• 1 R(+)-body ground(-)

Oscilloscope setting 

• 5 V/DIV (Y), 20 ms/DIV (X), DC range

Vehicle condition 

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

  Courtesy of MAZDA MOTORS CORP.

APP sensor No. 2 signal 

Accelerator pedal released 

Accelerator pedal depressed 

PCM terminals 

• 1X(+)-body ground(-)

Oscilloscope setting 

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

Vehicle condition 

• Switch the ignition to ON.
  Fig 3: APP Sensor (No. 2) Signal Waveform (Depressed)

  Courtesy of MAZDA MOTORS CORP.

Purge control 

PCM terminals 

• 1BA(+)-body ground(-)

Oscilloscope setting 

• 10 V/DIV (Y), 20 ms/DIV (X), DC range

Vehicle condition 

• Idle after warm up
  Fig 4: Purge Control Signal Waveform

  Courtesy of MAZDA MOTORS CORP.

A/F sensor heater control 

PCM terminals 

• 2A(+)-body ground(-)

Oscilloscope setting 

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

Vehicle condition 

• Idle (immediately after starting the engine)
  Fig 5: A/F Sensor Heater Control Signal Waveform

  Courtesy of MAZDA MOTORS CORP.

HO2S heater control 

PCM terminals 

• 2B(+)-body ground(-)

Oscilloscope setting 

• 5 V/DIV (Y), 1 s/DIV (X), DC range

Vehicle condition 

• Idle (immediately after starting the engine)
  Fig 6: HO2S Heater Control Signal Waveform

  Courtesy of MAZDA MOTORS CORP.

OCV control 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 7: OCV Control Signal Waveform

  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

CKP signal 

PCM terminals 

• 2W(+)-body ground(-)

Oscilloscope setting 

• 1 V/DIV (Y), 5 ms/DIV (X), DC range

Vehicle condition 

• Idle after warm up
  Fig 9: CKP Signal Waveform

  Courtesy of MAZDA MOTORS CORP.

IGT1, IGT2, IGT3, IGT4 control 

PCM terminals 

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

Oscilloscope setting 

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

Vehicle condition 

• Idle after warm up
  Fig 10: IGT1, IGT2, IGT3, IGT4 Control Signal Waveform

  Courtesy of MAZDA MOTORS CORP.

Generator field coil control 

PCM terminals 

• 2AA(+)-body ground(-)

Oscilloscope setting 

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

Vehicle condition 

• Idle after warm up
  Fig 11: Generator Field Coil Control Signal Waveform

  Courtesy of MAZDA MOTORS CORP.

Generator output voltage 

PCM terminals 

• 2AF(+)-body ground(-)

Oscilloscope setting 

• 2 V/DIV (Y), 2 ms/DIV (X), DC range

Vehicle condition 

• Idle after warm up
  Fig 12: Generator Output Voltage Signal Waveform

  Courtesy of MAZDA MOTORS CORP.

Fuel injection (#1, #2, #3, #4) control 

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 

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

Vehicle condition 

• Idle after warm up
  Fig 13: Fuel Injection (1, 2, 3, 4) Control Signal Waveform

  Courtesy of MAZDA MOTORS CORP.