Operation CHARM: Car repair manuals for everyone.

Oscilloscope Patterns and Waveforms

Cooling fan control signals




- PCM terminals: 1W(+)-body ground (-)
- Oscilloscope setting: 5 V/DIV (Y), 1 minute/DIV (X), DC range
- Vehicle condition: Idle after warm up (engine speed approx. 700 rpm, A/C ON)