Oscilloscope Patterns and Waveforms

Inspection Using An Oscilloscope (Reference)




Fuel injection control signal
- PCM terminal
- No.1:2A(+) <=> 3A(-)
- No.2:2D(+) <=> 3A(-)
- No.3:2G(+) <=> 3A(-)
- No.4:2J(+) <=> 3A(-)

- Oscilloscope setting: 2.0 V/DIV (Y), 20 ms/DIV (X), DC range
- Vehicle condition: Idling after warm-up.




IAC control signal
- PCM terminal: 2P(+) <=> 2Q(-)
- Oscilloscope setting: 2.0 V/DIV (Y), 25 ms/DIV (X), DC range
- Vehicle condition: Idling after warm-up (no electrical load).




Purge control signal
- PCM terminal: 3C(+) <=> 4A(-)
- Oscilloscope setting: 2.0 V/DIV (Y), 10 ms/DIV (X), DC range
- Vehicle condition:
- ECT: above 80 °C {176 °F}
- D range and 7.5 km/h {5 mph} or below.




IGT control signal
- PCM terminal:
- 3F(+) <=> 4A(-)
- 31(+) <=> 4A(-)

- Oscilloscope setting: 1.0 V/DIV (Y), 50 ms/DIV (X), DC range
- Vehicle condition: Idling after warm-up.




Generator field coil signal
- PCM terminal: 3M(+) <=> 4A(-)
- Oscilloscope setting: 0.5 V/DIV (Y), 2.5 ms/DIV (X), DC range
- Vehicle condition: Idling after warm-up (no electrical load).




Engine speed signal
- PCM terminal: 30(+) <=> 4A(-)
- Oscilloscope setting: 2.0 V/DIV (Y), 20 ms/DIV (X), DC range
- Vehicle condition: Idling.




Vehicle speed signal
- PCM terminal: 3T(+) <=> 4A(-)
- Oscilloscope setting: 1.0 V/DIV (Y), 10 ms/DIV (X), DC range
- Vehicle condition: Driving 50 km/h [31 mph].




SGC signal
- PCM terminal: 3V (+) <=> 4A(-)
- Oscilloscope setting: 2.0 V/DIV (Y), 20 ms/DIV (X), DC range
- Vehicle condition: Idling.




NE signal
- PCM terminal: 3Y(+) <=> 4A(-)
- Oscilloscope setting: 1.0 V/DIV (Y), 5.0 ms/DIV (X), DC range
- Vehicle condition: Idling




Oil control valve (OCV) signal
- PCM terminal: 4D(+) <=> 4A(-)
- Oscilloscope setting: 2.0 V/DIV (Y), 0.5 ms/DIV (X), DC range
- Vehicle condition: Idling after warm-up (no electrical load).




HO2S (front) signal
- PCM terminal: 4W(+) <=> 4A(-)
- Oscilloscope setting: 0.2 V/DIV (Y), 2.0 ms/DIV (X), DC range
- Vehicle condition: Idling after warm-up.