Completed a repair on a knock sensor, all good. No code. A week later code starts. Used Delphi on the one sensor I had to replace. Delphi is OEM to GM, as I understand. I sourced the generic wiring component, and did have to struggle to connect that pigtail to the factory harness. Now my code is set, and it states both sensors. I know the front sensor was in OK condition, not corroded, so I am discounting either of the sensors and focusing on the wire sub-harness or another cause.
As I study others battling this GM achilles heel, I see others also had to revisit the problem, throw more time and money at it. I would appreciate to hear what others have learned.
Where are your sensors located?
GM 6.0 knock sensors are 2 , located series circuit, top of intake. Piezo electric sensors, that monitor cylinder vibration from the knock. The vibration they feel pulses a 5V signal to computer to adjust emission controls and halt the ping.
Grounding is key, corrosion may cause impedance and result in volt drop, sending code back. I plan to clean block ground points, chdck before and sfter on the volt drop. You can simulate the knocking and function with a hammer.
Dealer claims you must use GM $$$ sensor. Many folks have swapped, and still have issue.
There are sensors UNDER the intake manifold. They are recessed into the valley cover. Most likely, water has filled those recesses and covered the knock sensors and their connectors. If so, those are rusted and need to be replaced. You'll need two knock senors, two pigtails, and some intake gaskets. From memory the Fel Pro intake is MS 98016 T. I try to use Delco sensors and pigtails.
Yup. Completed job. read up. Post job a week, codes set. Used Delphi sensor. 1 in front was fine, no corrosion. Its ALWSYS the rear that rusts gets the water. Tons of cleaning done.
I had code on rear only before, now code on both, so itsvthe connector, a less than ideal positive engagement, or rust on engine to harness ground points. I will insert a 1K resistor and fake the circuit with a bypass, see if it clears.
This was a odd one. After verifying my piezo sensors were correct range on resistance, and produced mV on knocking to the manifold, I started checking connections. The aftermarket replacement harness had been difficult connecting, and I had remembered that. As I was metering those posts, I see they are pushed off to side, not straight up the middle. Ordered tool set, re-pinned my factory harness end plastic housing, and voila, things working far better.
Many people posting about their post job error codes. Maybe this has happened to others as well. btw, I only changed one sensor, and so far, the codes haven't come back.