Originally Posted by Sc00by

My rear knock sensor went out last year with the same code. Mine definatly pulled timing and I definatly felt a difference. What happeds with these knock sensors on our LS engines is MAJOR corrosion issues. People who wash and detail their engines on a regular basis will have this problem. Because the knock sensors are located below a cheezy plastic cap under the intake water will seep in and pool up in the knock sensor cavity. It mainly affects the rear sensor but if your changing them you might as well do both. The harnes can become corroded as well. If its messed up change it. Mine was alright so its still installed without any problems. What I did to hopefully prevent this from happening again is use RTV and built a dam to block water from going into the cavity. Its about 1/2"-3/4" tall and wide and wraps about half way around the sensor. Its worked out great and have had no problems since.

Originally Posted by Evil Eric

I just read a comment from another member in the diagnostics forum that said that this code causes the computer to pull a constant 4* of timing. Ive got this exact code and I see 0 knock in my logs and the truck still runs great. Ill change it later in the summer when i get bored.

Originally Posted by DV2000NJ

Yeah definitely check. My dumb *** didn't when I had the manifold off.

At least when you pull yours off, a "more fun" manifold will be going on.