Knock Sensor???

After a normal weekend of mudding and then washing my truck I noticed that the Service Engine Light was on! OMG what did I do I wondered and I took it to the local Service Station on Post. They ran the Diag. and it came back with the code of "Knock Sensor 2 Low input". Has anyone ever had to replace one, in fact does anyone even know what it exactly does? The mechanic didnt really have much to say. Napa sells it for 34.99 and the local dealership priced it ~45. Thanks..... :evillol:

The knock sensors are located under the intake manifold. I have a hynes manual that does a pretty good job of explaining the replacement. Also, I think there is a TSB from Gm on these knock sensors. When you replace the one in the back, you have to build a little dam around it with RTV to keep water out. From what I read, water it the cause of most of these going out. As for what it does, it detects spark knock and sends infor to your pcm to adjust the timing.

WOW so are you saying that i have to remove the intake manifold to change the sensor? That sounds like alot of work. If you have anymore info i would greatly appriciate it and thanks for reply now i have some info atleast to go off of.

yes you have to remove the intake manifold to get to the knock sensors, it is hard on the back being bent over the motor and somewhat involved but not extremely difficult.

thank you very much :banghead: