Operation CHARM: Car repair manuals for everyone.

Oscilloscope Patterns and Waveforms

Vehicle speed signal (ATX)




- PCM terminals: 1J (+)-body ground (-)
- Oscilloscope setting: 1 V/DIV (Y), 2.5 minutes/DIV (X), DC range
- Vehicle condition
- Vehicle speed is 32 km/h (20 mph).

Input/turbine speed sensor (+) signal




- PCM terminals: 1M (+)-body ground (-)
- Oscilloscope setting: 500 mV/DIV (Y), 1 minute/DIV (X), DC range
- Vehicle condition: Idle after warm-up

Input/turbine speed sensor (-) signal




- PCM terminals:1Q (+)-body ground (-)
- Oscilloscope setting: 500 mV/DIV (Y), 1 minute/DIV (X), DC range
- Vehicle condition: Idle after warm-up.