CB99SS

I've gotten this code twice in the last two weeks. I recently intalled my cam and heads. The Dealer reset the PCM with the latest updates. I've intalled my edit file. Since then I've gotten this code P0327 Knock Sensor 1 Cirucuit Low Frequency.

What is causing this? Do I need a new Knock Sensor? I've never had this problem before.

Thanks for the help.

Predator

You need to replace your front knock sensor. Most likely, water got under your intake. GM has a TSB for that very problem.

CB99SS

I wasn't getting this code until the PCM was reflashed with the new Chevrolet updates.

I drove the car for a week before the computer was reflashed.

Thanks

Predator

It has no relation to having your pcm reflashed.

What's strange though is that the rear KS usually goes first. You might as well swap them both out, and replace the harness while you're at it. The GM TSB says to make a "dam" with RTV around the KS rubber boots, leaving an opening in the dam for water to drain out. They also say to remove the two foam squares under the intake. I also put some RTV around where the wire enters the rubber boots. You'd probably have to do this eventually anyway.

PlowTown Missile

Dealership just replaced mine. Sucks because Ed Wright is going to delete then in a month anyway.

Predator

Just curious, why would you have EW delete your KS codes? The whole point of going through all this trouble is to have working knock sensors.

As an example, my problem started with P0332 (rear ks low voltage), so I replaced both knock sensors, and the harness, and then both codes came back (P0327 & P0332). I ended up pulling the intake again and found my new wiring harness was crushed (my mistake for routing the wire along the side of the valley). I reordered two more knock sensors, and yet another harness, and finally it's fixed. The point is that I had LS1 Edit and could have easily deleted the ks circuit codes. If you don't mind me saying, I think you should keep your knock sensors functional, at all costs.

CB99SS

Well I replaced the front knock sensor and Harness. I'm still getting the code. Now I'm also getting the rear low frequency code.

Now what should I try?

Thanks

Predator

I can relate my experience to you. First I got P0332, so I pulled the intake and replaced both knock sensors, and the harness. Things were cool for a couple days, then both knock sensor codes came up (P0332 and P0327). I didn't believe the computer because I felt it couldn't be the knock sensors or harness because I had replaced them a couple days prior. So I fiddled around with my tuning thinking that might be causing the codes. I researched anything I could find related to knock sensors and I learned that those two codes are ONLY related to a malfuctioning ks circuit. Just one of the codes means it's a bad knock sensor; both codes mean that it's either a faulty harness or a problem with the pcm. With both codes the computer is saying that it's NOT the knock sensors, but the harness or pcm itself (what are the odds of both knock sensors going bad at the same time). So I pulled my intake, again, and the wire was crushed under the intake. I wasn't careful about routing the wire correctly under the intake. The best place to rout it is in the middle of the passenger side of the valley. Also, I have an LS6 intake and there's less clearance than the stock LS1 intake. So I took a palm sander and removed some of the criss-crossed black plastic material under the intake corresponding to the side that the wire was to be routed. I did the GM TSB saying to create a dam with RTV around the rubber boots, and I removed the foam squares under the intake as the TSB stated. My problem was solved. I think it's extremely unlikely that your pcm is bad, so my experience says either damaged or faulty KS wire.

CB99SS

Looks like I will be pulling the intake again. How can I check just the knock sensor?

Thanks for everyones help.