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Persistent Knock Sensor Codes - *BUT* Sensors & Harness Test Good

Tom Lundin
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Tom Lundin New Member

Tom Lundin

Posted
Posted

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.

CamGTP Senior Enthusiast

CamGTP

Posted
Posted

I've seen the codes come back with aftermarket knock sensors, always had good luck with AC delco units.

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