• If you currently own, previously owned or want to own an Avalanche, we welcome you to become a member today. Membership is FREE, register now!

Knock Sensor Code P0327

cutiger

Full Member
Joined
Nov 13, 2002
Messages
37
Location
Lexington, SC
This is my first post, so don't beat me up too bad.  My Service Engine light came on and I had it checked.  The code is P0327 - Knock Sensor 1 - Circuit Low Input.  I had it reset and it came back within a day.  I had it reset again, and again it came back.  I bought the knock sensor from Autozone for about $40.  Then I started investigating where it is located.  I searched this site and found detailed instructions on replacing the sensor.  I was shocked to find that I needed to remove the entire intake manifold to change the sensor.  Before I take this on (which I don't have a problem doing), I want to make sure that it is necessary to replace the sensor.  Is it possible that a connection is loose or corroded?  Has anyone else experienced this problem and what did you determine?  Should I tackle this or take it somewhere and pay (probably) megabucks?  Any help or advice would be appreciated.
 
Replaced MANY knock sensors, the hole they are in(there is 2 k.s. in your truck, make sure you replace the right one) fills with water and corrodes the tar out of them, also be sure you use a inch pound torque wrench and follow the tightening procedure when you install the intake, or else you may end up replacing the intake, its plastic and warps easy!!!!


Nice to have ya here!!!
 
Thanks for the input.  I'm thinking that I should go ahead and replace both knock sensors while I am in there.  The sensor that I bought had some instructions in the box that indicated that I should put a bead of RTV Silicon around the well that the sensor is in to prevent water from running into it in the future.  What are your thoughts?  Also, how long should I allow to remove the intake, replace the knock sensors and then replace the intake?  Is this an all day project or a Sunday afternoon one?
 
I just had the Service Engine Soon light come on for the first time yesterday. I stopped by Autozone and had them read the code. My code comes up P0332 which comes out to be low voltage from knock sensor 2. I went ahead and reset the code for now to see if it comes back.

If it comes back I guess I will go ahead and replace both sensors and do the RTV trick. Hopefully it will not come back. I am not looking forward to having to replace the sensor if that is what is bad... :E: :needhug:

Thanks to everyone for the input and the detailed instructions on how to do this (y)
 
I just got done replacing both of my knock sensors. It took me about 6 hrs.

Here is a few pics of what the sensors looked like. The one that is in pretty good shape is the front the one that is corroded beyond recognition was the rear one. The hole for the rear sensor was about half way filled up with water. I also put a bead of RTV around the hole that the sensor go into to prevent water from getting into the holes again.

Now all I have to do is go down to the local auto parts store to get them to reset the code and the service engine soon light.

 

Attachments

  • knocksensor.JPG
    knocksensor.JPG
    38.8 KB · Views: 718
  • knocksensor1.JPG
    knocksensor1.JPG
    40 KB · Views: 711
The code will reset itself if the condition has cleared, no reason to go someplace for that.
 
02 Z71 said:
I just got done replacing both of my knock sensors. It took me about 6 hrs.

Here is a few pics of what the sensors looked like. The one that is in pretty good shape is the front the one that is corroded beyond recognition was the rear one. The hole for the rear sensor was about half way filled up with water. I also put a bead of RTV around the hole that the sensor go into to prevent water from getting into the holes again.

Now all I have to do is go down to the local auto parts store to get them to reset the code and the service engine soon light.

do you have a pix where there are located
 
Loggie said:
do you have a pix where there are located

Sorry I don't  :E: I ended up doing the knock sensor replacement at a friends shop because of snow and ice, so I didn't have my camera with me. :E: :E: :E:

The sensors are physically located directly underneath the intake plenum. The one in the rear is kind of a beotch to get to if you don't get the intake all of the way off. I didn't have the metal tool for releasing the fuel lines so one was still attached. I couldn't get the intake completing out of the way, but I got the job done. So a word of advice is to make sure that you get the metal fuel line release tool rather than the cheapie plastic set like I got.
 
  :cry:    :cry:    :cry:   

:E:    :E:    :E:

This is not the info I wanted to read.  Hmmmm, maybe I will just turn the sensor off for a while until I get a chance to do this.  :E:  Or at least until I take it for the SMOG test.  >:D
 
INresponse said:
  :cry:     :cry:     :cry:   

:E:    :E:    :E:

This is not the info I wanted to read.  Hmmmm, maybe I will just turn the sensor off for a while until I get a chance to do this.   :E:  Or at least until I take it for the SMOG test.   >:D

I don't think I'd want to run around without the knock sensors too much if I had a Blower. 

Detonation is bad for NA engines.  It's very bad for FI engines.

If I remember correctly, #7 cylinder is the most likely one to go learn.  That would be the rear driver side cylinder that's watched by the rear Knock Sensor.  Not an ideal combination.
 
I don't have an inch pound torque wrench or the fuel line tool.  My friend said he would do it for $200.00 plus parts.  Heading there now to drop it off.  I am also telling him to put the RTV around the hole to prevent a repeat.
 
INresponse said:
I don't have an inch pound torque wrench or the fuel line tool.  My friend said he would do it for $200.00 plus parts.  Heading there now to drop it off.  I am also telling him to put the RTV around the hole to prevent a repeat.

That's a good deal. Good luck  (y)
 
Is there anything else you should do with this job? like oils or gasket replacement?

thanks, I'm new here and Have a 2002 Avalanche 1500 76k. love it.

02 Z71 said:
Sorry I don't  :E: I ended up doing the knock sensor replacement at a friends shop because of snow and ice, so I didn't have my camera with me. :E: :E: :E:

The sensors are physically located directly underneath the intake plenum. The one in the rear is kind of a beotch to get to if you don't get the intake all of the way off. I didn't have the metal tool for releasing the fuel lines so one was still attached. I couldn't get the intake completing out of the way, but I got the job done. So a word of advice is to make sure that you get the metal fuel line release tool rather than the cheapie plastic set like I got.
 
cokamoe21 said:
Is there anything else you should do with this job? like oils or gasket replacement?

thanks, I'm new here and Have a 2002 Avalanche 1500 76k. love it.

There is nothing else to do when you do this job that is related to it. Your will need a set of intake plenum gaskets, the knock sensors and as I said in my previous post, I would highly recommend getting the good metal fuel line release tool. I had the cheap plastic release tool. It was a pain in the a$$ to get the fuel lines to release with the cheap plastic tool. As a matter of fact, I couldn't even get one of the fuel lines to release with the plastic tool. I don't remember what size the fuel lines are but if I remember correctly my local auto parts store sells 2 different size metal tools and I believe that it is the larger of the 2. Oh yes, you will also need a tube of RTV to put around the knock sensor holes to help keep water out in the future. You will also need a vacuum cleaner with a long hose to vacuum up all of the debris that will be underneath the intake (dirt, leaves, etc) or course making sure that none of that debris get down inside the engine.
 
When you replace the knock sensor, you also have to replace the wiring harness that goes to the sensor.  There is no way to clean the terminal and there it no way to know for sure that even if you cleaned the terminal that it wouldn't corrode again.

If you do not have a tool, but you own tools - it is a good idea to buy the plastic tool.  Even if you only use it once, you can always take it back to Advance Auto Parts - or where ever you bought it and get your money back.

Or you can make your own tool if you have a knob off a old propane grill.  You just machine a slot on one side of the knob.  Then you put the line inside the slot and then you turn it 1/4 of a turn while pressing in and the line should release.

GM recommends that you build a mountain of RVT on top of the oil galley where the sensor goes, that way it diverts the water to the left and the right of the sensors.

Some people throws away the foam that is under the manifold since it doesn't do much anyways.

Power washing the engine is a no no with the 5.3 / 6.0

That is probably where the water came from that was under my intake manifold.
 
i am having the hardest time getting my knock sensors out please help!

I have a 2002 Chevy Avy Z71 5.3L and I have my intake manifold and everything out but ive been loosing the Knock Sensors for like 10 minutes each. What the heck is going on here?
 
If you have in fact verified that the knock sensors are indeed turning when you are loosening them, you will probably need a pair of long nosed needle nose pliers to reach down into the hole to pull them out.
 
Well mine went out yesterday. :E:
So you can get both the sensors and wire harness at an auto parts not a stelealer?
What gasgets are required,and which ATV blue,black,ext?
When taking off the fuel lines what about the fuel pressure is there a need to relieve it and how?
So I love to detail my rigs did not know about the sensor problems so whats I guy to do?
Leave the foam out and blow the engine off with air; If you have no compressor
washing with engine warm  and how many 0 to 100 blast   :drive: 100 to 0  :woohoo:
will take care of the water on the sensors?

JV
 
JVZL1 said:
Well mine went out yesterday. :E:
So you can get both the sensors and wire harness at an auto parts not a stelealer?
What gasgets are required,and which ATV blue,black,ext?
When taking off the fuel lines what about the fuel pressure is there a need to relieve it and how?
So I love to detail my rigs did not know about the sensor problems so whats I guy to do?
Leave the foam out and blow the engine off with air; If you have no compressor
washing with engine warm  and how many 0 to 100 blast   :drive: 100 to 0  :woohoo:
will take care of the water on the sensors?

JV

You cam get the sensor at any auto parts store.
You should not need to replace the wiring harness, if you do, you will have to get it from the dealer.
You will need a set of intake plenum gaskets which you can get at any auto parts store (probably special order)  but you will not need any kind of sealer to seal them.
There is a schrader value to relieve the fuel pressure right on the fuel pressure rail on the drivers side. it is basically like a valve stem, just push the center to relieve the pressure but beware that fuel will spray out.
Read the instructions here in this thread about building up a "dam" of RTV (red) around the knock sensors to help keep the water out of the sensors.
Yes take both foam dams out from under the intake plenum to help keep water from being trapped under the intake plenum.

Basically if you read all of the instructions in this thread, all of your questions will be answered.
 
Thanks Brian,
I went back and read it all once more. Ordered two sensors and the gaskets set,
should be here mid week. Still not sure on the wire harness, will check and see if the dealer
has them and wait until I have them off.
With these sensors what is the best way to clean the engine. I was using a spray and rinsing
it of with a hose.
With putting the RTV dam on and raising the front of the AVY work keeping the water out?
Sure would like to keep my engine clean.
This site is so impressive with all who help and guide us TEC challenged souls.
(y) THANKS TO ALL
JV
 
I have an 02 AV and recently drove thru a large puddle and since then my CEL has been on. My mechanic checked the code and said the knock sensors need to be replaced. Said it was a big job removing the manifold and estimated quote was for two knock sensors and the intake seal for roughly $ 600.00 ( parts 320 + labor ). I'm not mechanically inclined so I need to rely on trustworthy mechanics. Is this pricing far off?
 
JAMO said:
I have an 02 AV and recently drove thru a large puddle and since then my CEL has been on. My mechanic checked the code and said the knock sensors need to be replaced. Said it was a big job removing the manifold and estimated quote was for two knock sensors and the intake seal for roughly $ 600.00 ( parts 320 + labor ). I'm not mechanically inclined so I need to rely on trustworthy mechanics. Is this pricing far off?

That probably is a reasonable estimate because it is a time consuming job. The $320 for parts does sound a little bit expensive. I just looked @ the Autozone website and the knock sensors are $48/ea and the manifold gasket is $78 and $56/ea and $92 @ Napa. If the mechanic is someone that you know is dependable and will do the job right, go for it.

You could also call around for more estimates to some other dependable shops but I say since you call this guy "your mechanic", I say go ahead and give him the business but maybe ask him about the parts cost estimate.
 
Thanks for the advice. I did check pricing and saw costs ranging from $ 43-77 per sensor and $ 95 for the seal. I may see if my mechanic will let me supply my own parts to save some $$. I've only been using him for a short period of time and was told he is slightly more expensive than other area mechanics but does good honest work, is very reliable/trustworthy and not out to screw customers. So far he's been up front and honest with me so we'll see what happens. Thanks again.
 
Just after I purchased every thing I needed to replace my knock sensors my Service Engine light went out :E:. I will still be replacing them.
IS there any thought of filling the sensor cavity with Dielectric silicone and putting the RTV dam around the top?
Being the manifold is coming off is there any maintenance to be done to the manifold (it is plastic right)
and injectors (like cleaning, new seals)?
My AVY is at 98k.
JV
 
Back
Top