Operation CHARM: Car repair manuals for everyone.

Oscilloscope Patterns and Waveforms

Inspection Using An Oscilloscope (Reference)

Fan control signal




- PCM terminals
- 69(+) - 26(-)

- Oscilloscope setting
- 2 V/DIV (Y), 0.2 ms/DIV (X), DC range

- Vehicle condition
- Idle after warm up (no load)