Ok I've done some reading tonight and have some tests to run. I'm going to lay them out here both so I can reference it tomorrow but also for anyone else that might came along and find any of this stuff useful.
First I want to start with this: Piezoelectric microphone utilize contact between a diaphragm and piezoelectric materials to produce a very small electric signal.
Based on that definition and the apparent differences in the knock sensor wire between
@Turbo4whl truck and mine. Both our trucks call for the same knock sensor and the same module. I think that difference is simply GM decided the shielding isn't necessary.
On to testing. Our knock sensor should show a resistance of about 95K to 105K ohms.
Under dash pin testing: Brown wire ground, obviously needs to be a good ground.
Pink 12 volts key on
The other connections are for the pick up coil and module, which is there was a break in any of those the truck would not likely run, still it might be worthwhile to run continuity tests on those wires. Last is the tip in switch which could literally fall off the truck and the system would still detect knock, it just wouldn't pull back timing briefly when the throttle is mashed.
Check to make sure all connections are clean and tight.
Knock sensor test. Our knock sensors produce a small amount of AC voltage which can be read on a multimeter. According to what I have just read the knock sensor will produce a small amount of voltage anytime the engine is running, it just produces a larger amount (still very small) when pinging is present. So that is how the system works and why a ESC module is necessary. The ESC module monitors the knock sensor voltage, to be clear it reads what the knock sensor is producing for voltage and at whatever the cut off point is when voltage gets above that it does something with the purple wire to the ignition module. Whether it feeds voltage in our grounds it out I don't know, and while it would be nice to know it's not imperative. So working with the ESC module unplugged and bypassed by jumping the purple and green wires together, fire the truck up. Revving the engine to 2,000 RPM, connect a DVM to the brown wire and blue wire with the brown being the negative and blue being positive. Should see more than 80 millivolts, this is .080 AC volts NOT DC VOLTS.
So using the above tests I should be able to check the knock sensor, check the wiring, and by testing everything around it, see if the module itself is at fault or not.
That's what I've learned.
