I've been plague by a "knock sensor" check engine light that won't go away. I check the knock sensor while still bolted to the engine block and got these readings at 2K-rpm:
DMM: ~20mV AC, 5.5M-Ohm. Scope: ~20mV or ~ 30mV peak-to-peak when back-probe connector. ECU to sensor supply power ~ 5VDC, when connected ~ 3.8VDC.
I remove the sensor from the engine block to test bench and vibrate it to achieve this readings:
DMM: 76mV AC, 576K-Ohm. Scope: 76mV peak-to-peak .
I reinstall the sensor into the vehicle and reset the ECU and no improvements. Normal torque is about 50-lb? Has the sensor gone bad/aged or the data retrieval technique is flawed?
Thanks