2003 Mazda 6 L4-2.3LFACTORY OEM SERVICE PROCEDURE

Oscilloscope Patterns and Waveforms

Inspection Using An Oscilloscope (Reference)

Factory service manual diagram



IGT1, IGT2 control signals
PCM terminals
IGT1 (No.1 and No.4): 1A(+) - 1D(-)
IGT2 (No.2 and No.3): 1B(+) - 1C(-)

Oscilloscope setting
- 4 V/DIV (Y), 0.01 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up (engine speed approx. 650 rpm, no load, P/S off, A/C off)

Factory service manual diagram



Generator output voltage signal
PCM terminals

1AA(+) - 2AC(-)

Oscilloscope setting
- 2 V/DIV (Y), 2 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up (engine speed approx. 650 rpm, no load, P/S off, A/C off)

Factory service manual diagram



HO2S (front) signal
PCM terminals

1AB(+) - 2H(-)

Oscilloscope setting
- 0.1 V/DIV (Y), 400 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up (engine speed approx. 650 rpm, no load, P/S off, A/C off)

Factory service manual diagram



Generator field coil control signal
PCM terminals

1AD(+) - 1C(-)

Oscilloscope setting
- 0.5 V/DIV (Y), 1 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up (engine speed approx. 650 rpm, no load, P/S off, A/C off)

CKP sensor signal

Factory service manual diagram



(+)
PCM terminals

- 2D(+) - 2H(-)

Oscilloscope setting
- 2 V/DIV (Y), 4 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up (engine speed approx. 650 rpm, no load, P/S off, A/C off)

Factory service manual diagram



(-)
PCM terminals

- 2G(+) - 2H(-)

Oscilloscope setting
- 2 V/DIV (Y), 4 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up (engine speed approx. 650 rpm, no load, P/S off, A/C off)

Factory service manual diagram



VSS signal
PCM terminals

2I(+) - 2AC(-)

Oscilloscope setting
1 V/DIV (Y), 10 ms/DIV (X), DC range

Vehicle condition
Drive the vehicle with approx. 10 km/h {6.2 mph}

CMP sensor signal

Factory service manual diagram



(+)
PCM terminals

2J(+) - 2H(-)

Oscilloscope setting
- 1 V/DIV (Y), 10 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up (engine speed approx. 650 rpm, no load, P/S off, A/C off)

Factory service manual diagram



(-)
PCM terminals

- 2M(+) - 2H(-)

Oscilloscope setting
- 1 V/DIV (Y), 10 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up (engine speed approx. 650 rpm, no load, P/S off, A/C off)

Factory service manual diagram



HO2S (front) heater control signal
PCM terminals

4A (+) - 1C(-)

Oscilloscope setting
- 4 V/DIV (Y), 200 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up (engine speed approx. 650 rpm, no load, P/S off, A/C off)

Factory service manual diagram



OCV control signal
PCM terminals

4M (+) - 1C(-)

Oscilloscope setting
- 2 V/DIV (Y), 0.8 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up (engine speed approx. 650 rpm, no load, P/S off, A/C off)

Factory service manual diagram



Purge control signal
PCM terminals

- 4U(+) - 1C(-)

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

Vehicle condition
- Idle after warm up (engine speed approx. 650 rpm, no load, P/S off, A/C off)

Factory service manual diagram



Fuel injection control
PCM terminals

- Fuel Injection No.1: 4Z(+) - 1C(-)
- Fuel Injection No.2: 4W(+) - 1C(-)
- Fuel Injection No.3: 4AD(+) - 1C(-)
- Fuel Injection No.4: 4AA(+) - 1C(-)

Oscilloscope setting
- 4 V/DIV (Y), 10 ms/DIV (X), DC range

Vehicle condition
- Idle after warm up (engine speed approx. 650 rpm, no load, P/S off, A/C off)
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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