Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2007 Mazda Mazdaspeed3 L4-2.3L TurboFACTORY OEM SERVICE PROCEDURE
Oscilloscope Patterns and Waveforms
Inspection Using An Oscilloscope (Reference) Fan control module signal

PCM terminals
- 1AE (+)-body ground (-)
Oscilloscope setting
- 5 V/DIV (Y), 20 ms/DIV (X), DC range
Vehicle condition
- Idle after warm up (no load, P/S off, A/C off)
HO2S (front) heater control signal

PCM terminals
- 2C (+)-body ground (-)
Oscilloscope setting
- 2 V/DIV (Y), 20 ms/DIV (X), DC range
Vehicle condition
- Idle after warm up (no load, P/S off, A/C off)
CMP sensor signal

PCM terminals
- 2S (+)-body ground (-)
Oscilloscope setting
- 2 V/DIV (Y), 100 ms/DIV (X), DC range
Vehicle condition
- Idle after warm up (no load, P/S off, A/C off)
CKP sensor signal

PCM terminals
- 2W (+)-body ground (-)
Oscilloscope setting
- 2 V/DIV (Y), 5 ms/DIV (X), DC range
Vehicle condition
- Idle after warm up (no load, P/S off, A/C off)
Wastegate control solenoid valve signal

PCM terminals
- 2AA (+)-body ground (-)
Oscilloscope setting
- 20 V/DIV (Y), 20 ms/DIV (X), DC range
Vehicle condition
- Ignition switch to the ON position
Purge control signal

PCM terminals
- 2AB (+)-body ground (-)
Oscilloscope setting
- 10V/DIV (Y), 20ms/DIV (X), DC range
Vehicle condition
- Engine speed is 2,000 rpm
OCV signal

PCM terminals
- 2AF (+)-body ground (-)
Oscilloscope setting
- 2.5 V/DIV (Y), 1 ms/DIV (X), DC range
Vehicle condition
- Idle after warm up (no load, P/S off, A/C off)
Generator field coil control signal

PCM terminals
- 2AI (+)-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)
Generator output voltage signal

PCM terminals
- 2AJ (+)-body ground (-)
Oscilloscope setting
- 2 V/DIV (Y),1 ms/DIV (X), DC range
Vehicle condition
- Idle after warm up (no load, P/S off, A/C off)
IGT1, IGT2, IGT3, IGT4 control signals

PCM terminals
- IGT1 (No.1): 2BA (+)-body ground (-)
- IGT2 (No.2): 2AW (+)-body ground (-)
- IGT3 (No.3): 2AX (+)-body ground (-)
- IGT4 (No.4): 2AT (+)-body ground (-)
Oscilloscope setting
- 2 V/DIV (Y), 20 ms/DIV (X), DC range
Vehicle condition
- Idle after warm up (no load, P/S off, A/C off)
Fuel injection 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), 20 ms/DIV (X), DC range
Vehicle condition
- Idle after warm up (no load, P/S off, A/C off)
Fuel injection control (+)

PCM terminals
- Fuel injection No.1, No.4: 2BG (+)-body ground (-)
- Fuel injection No.2, No.3: 2BH (+)-body ground (-)
Oscilloscope setting
- 20 V/DIV (Y), 400 ns/DIV (X), DC range
Vehicle condition
- Idle after warm up (no load, P/S off, A/C off)
PCM terminals
- 1AE (+)-body ground (-)
Oscilloscope setting
- 5 V/DIV (Y), 20 ms/DIV (X), DC range
Vehicle condition
- Idle after warm up (no load, P/S off, A/C off)
HO2S (front) heater control signal
PCM terminals
- 2C (+)-body ground (-)
Oscilloscope setting
- 2 V/DIV (Y), 20 ms/DIV (X), DC range
Vehicle condition
- Idle after warm up (no load, P/S off, A/C off)
CMP sensor signal
PCM terminals
- 2S (+)-body ground (-)
Oscilloscope setting
- 2 V/DIV (Y), 100 ms/DIV (X), DC range
Vehicle condition
- Idle after warm up (no load, P/S off, A/C off)
CKP sensor signal
PCM terminals
- 2W (+)-body ground (-)
Oscilloscope setting
- 2 V/DIV (Y), 5 ms/DIV (X), DC range
Vehicle condition
- Idle after warm up (no load, P/S off, A/C off)
Wastegate control solenoid valve signal
PCM terminals
- 2AA (+)-body ground (-)
Oscilloscope setting
- 20 V/DIV (Y), 20 ms/DIV (X), DC range
Vehicle condition
- Ignition switch to the ON position
Purge control signal
PCM terminals
- 2AB (+)-body ground (-)
Oscilloscope setting
- 10V/DIV (Y), 20ms/DIV (X), DC range
Vehicle condition
- Engine speed is 2,000 rpm
OCV signal
PCM terminals
- 2AF (+)-body ground (-)
Oscilloscope setting
- 2.5 V/DIV (Y), 1 ms/DIV (X), DC range
Vehicle condition
- Idle after warm up (no load, P/S off, A/C off)
Generator field coil control signal
PCM terminals
- 2AI (+)-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)
Generator output voltage signal
PCM terminals
- 2AJ (+)-body ground (-)
Oscilloscope setting
- 2 V/DIV (Y),1 ms/DIV (X), DC range
Vehicle condition
- Idle after warm up (no load, P/S off, A/C off)
IGT1, IGT2, IGT3, IGT4 control signals
PCM terminals
- IGT1 (No.1): 2BA (+)-body ground (-)
- IGT2 (No.2): 2AW (+)-body ground (-)
- IGT3 (No.3): 2AX (+)-body ground (-)
- IGT4 (No.4): 2AT (+)-body ground (-)
Oscilloscope setting
- 2 V/DIV (Y), 20 ms/DIV (X), DC range
Vehicle condition
- Idle after warm up (no load, P/S off, A/C off)
Fuel injection 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), 20 ms/DIV (X), DC range
Vehicle condition
- Idle after warm up (no load, P/S off, A/C off)
Fuel injection control (+)
PCM terminals
- Fuel injection No.1, No.4: 2BG (+)-body ground (-)
- Fuel injection No.2, No.3: 2BH (+)-body ground (-)
Oscilloscope setting
- 20 V/DIV (Y), 400 ns/DIV (X), DC range
Vehicle condition
- Idle after warm up (no load, P/S off, A/C off)
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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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