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Home >> Mazda >> 2011 >> CX-7 s Touring, 2.3 L, AWD >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System [L3 With TC] >> Pcm Inspection >> Inspection Using An Oscilloscope (Reference)
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Inspection Using An Oscilloscope (Reference)

Fan control module signal 

PCM terminals 

1R (+)-body ground (-) 

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) 

Fig 1: Fan Control Module Signal Waveform
G04859775Courtesy of MAZDA MOTORS CORP.

Generator field coil control signal 

PCM terminals 

1AW (+)-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) 

Fig 2: Generator Field Coil Control Signal Waveform
G04859782Courtesy of MAZDA MOTORS CORP.

Generator output voltage signal 

PCM terminals 

1AX (+)-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) 

Fig 3: Generator Output Voltage Signal Waveform
G04859783Courtesy of MAZDA MOTORS CORP.

A/F sensor 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) 

Fig 4: A/F Sensor Heater Control Signal Waveform
G04859776Courtesy of MAZDA MOTORS CORP.

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) 

Fig 5: CMP Sensor Signal Waveform
G04859777Courtesy of MAZDA MOTORS CORP.

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) 

Fig 6: CKP Sensor Signal Waveform
G04859778Courtesy of MAZDA MOTORS CORP.

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 

Fig 7: Wastegate Control Solenoid Valve Signal Waveform
G04859779Courtesy of MAZDA MOTORS CORP.

Purge control signal 

PCM terminals 

2AB (+)-body ground (-) 

Oscilloscope setting 

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

Vehicle condition 

Engine speed is 2,000 rpm 

Fig 8: Purge Control Signal Waveform
G04859780Courtesy of MAZDA MOTORS CORP.

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) 

Fig 9: OCV Signal Waveform
G04859781Courtesy of MAZDA MOTORS CORP.

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) 

Fig 10: IGT1, IGT2, IGT3, IGT4 Control Signals Waveform
G04859784Courtesy of MAZDA MOTORS CORP.

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) 

Fig 11: Fuel Injection Control (-) Waveform
G04859785Courtesy of MAZDA MOTORS CORP.

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 μs/DIV (X), DC range 

Vehicle condition 

Idle after warm up (no load, P/S off, A/C off) 

Fig 12: Fuel Injection Control (+) Waveform
G04859786Courtesy of MAZDA MOTORS CORP.