[QUOTE=last993;1273779]Got to love this forum....

Now I see what triggers the K.S. You said to test it w/ a scope. Any written procedures that I can access to ?..would like to ensure that it's the sensor that went bad before ordering a new part.

A/C coupling
Amplitude-50mV/div
Time base -1 mS/div
Auto-trigger.

I have been told that a simple diyer tool is to use a small speaker or headphones to pick up the audio output , but I have never tried it.
I would imagine it works the same way you can test a speaker by scratching the leads across a 1.5 dc flashlight battery... makes sense. I will try it next time I have one laying around.
You actvate the piezo [ Knock sensor] by tapping something metalic near its vicinity... no need to have key On power , as the sensor is an a/c crystal generator when vibration activated ...............this is not to compare to scope testing, but it should at least tell one if the sensor is working.