I know these knock sensor posts are ubiquitous but I've searched forums and elsewhere online and not found this particular circumstance -- everything tests good with the multimeter.
I was getting P0327 and P0332 codes, so low circuit voltage, both banks. I replaced the knock sensors and harness. Codes came back. I researched online for tests for the sensors and for the main wiring harness after the connector. I did those tests.
Sensors both show 100.4 kiloohms, which is right where the GM manuals say means good.
On the harness side, I get a good reference voltage on both bank1 and bank2 - 1.4 millivolts with key off, 18.4 millivolts with key on.
Also on the harness side, I tested continuity on both wires -- that is, one lead on light blue bank2 spade at connector harness side, other lead on pin 11 at PCIM -- continuity; same on dark blue bank1 spade at connector harness side and pin 51 at PCIM - continuity.
So now I'm stumped: sensors test good, wiring harness tests good; still codes come back after clearing.
If anyone has any suggestions on other causes, tests, solutions, I will be exceedingly grateful.
I know these knock sensor posts are ubiquitous but I've searched forums and elsewhere online and not found this particular circumstance -- everything tests good with the multimeter. I was getting P0327 and P0332 codes, so low circuit voltage, both banks. I replaced the knock sensors and harness. Codes came back. I researched online for tests for the sensors and for the main wiring harness after the connector. I did those tests. Sensors both show 100.4 kiloohms, which is right where the GM manuals say means good. On the harness side, I get a good reference voltage on both bank1 and bank2 - 1.4 millivolts with key off, 18.4 millivolts with key on. Also on the harness side, I tested continuity on both wires -- that is, one lead on light blue bank2 spade at connector harness side, other lead on pin 11 at PCIM -- continuity; same on dark blue bank1 spade at connector harness side and pin 51 at PCIM - continuity. So now I'm stumped: sensors test good, wiring harness tests good; still codes come back after clearing. If anyone has any suggestions on other causes, tests, solutions, I will be exceedingly grateful.