P0332 Knock Sensor 2002 Sierra..help !

djscottymiami · October 11, 2011

Ok, I ended up doing this on the weekend. Few things I can point out to other people.

1 - I left the fuel injectors / rails on the manifold. Just disconnected the fuel lines using a tool I bought from Princess Auto (Harbour Freight Equivalent). Had more of a tough time with the fuel injector connectors. Wasted an hour figuring out how to properly disconnect the first one. Once I figured it out it wasn't too bad.

2 - Make sure you have the proper torque wrench in order to tighten the manifold bolts back down. I got burnt bad on this. I live 30 mins from the closest city and had to drive in to get one. The torque specs in my Haynes manual said to torque the bolts to 44inch-lbs then to 89inch-lbs. I had to drive in to get one that could get to these specs. I didn't think twice about it since the intake is made out of plastic and I didnt want it to leak.

3 - I spent a bit of time to clean the intake out. My truck used to be a farm truck for most of its 100,000miles and was run with dyed fuel so the dye was fairly prevalent when I got into there..

I'm not an automotive mechanic by any means but I'd consider myself slightly mechanically inclined and this job took me the better part of the afternoon. It was obvious when I got into the knock sensors why it was throwing the code (see the pictures below). Cleaned all the gasket surfaces with a razor blades, put a bead of black RTV around the new boots and it all went back together easier.. (1.5hrs to reassemble probably compared to the disassembly).

Now can anyone take a guess which one was the rear knock sensor?

And my dirty engine bay just for the hell of it

I'm glad I attempted this by myself. I've haven't really ever tackled a big job like this (replacing intake manifold gaskets) so it was a good learning experience

capecupcake · October 15, 2011

I just joined this forum after searching the internet for the code my mechanic gave me. I just bought a 2003 Chevy Silverado 1500 used from a dealer. I recently got it inspected and right after, the check engine light came on. I took it to my mechanic and here is what the work order said:

"SCANNED COMPUTER, PULLED CODE P0332-KNOCK SENSOR. DOES HAVE TSB FOR INTAKE LEAKING COOLANT ONTO SENSOR. WILL NEED TO REPLACE SENSOR AND UPDATED WIRING HARNESS. DOES HAVE UPDATED GASKETS FOR INTAKE. TSB #02-06-04023A"

They quoted me a cost of $850 for this repair. I can't afford that after just buying this truck. The truck runs very smooth and I have not heard any pings. I know the dealer must have power washed the engine as it was spotless. I am thinking this is what set the code off after reading so many things about this online. I am by no means a mechanic, but I am wondering if this is something I should try to repair myself. I have only done the basics when it comes to auto repair-oil changes and replaced a motor in a window. Am I crazy to think I could do this? I just can't see paying that much for it when I know the parts are not that expensive and labor should not be that much.

Also, I read that AutoZone will check for codes and clear them so that the light will go out. Is that true?

Now, I know what most of you are thinking. Here is a female who is talking about doing something that is way beyond her abilities. Well, I am no girly-girl. I like a challenge and have repaired numerous home appliances just by researching what to do. I hate to pay someone else so much for something I can do myself. So, what are your opinions and advice. I would most likely have some help from my brothers, who also are not mechanics, but like a good challenge.

bcraytor · October 25, 2011

I just joined this forum after searching the internet for the code my mechanic gave me. I just bought a 2003 Chevy Silverado 1500 used from a dealer. I recently got it inspected and right after, the check engine light came on. I took it to my mechanic and here is what the work order said:

"SCANNED COMPUTER, PULLED CODE P0332-KNOCK SENSOR. DOES HAVE TSB FOR INTAKE LEAKING COOLANT ONTO SENSOR. WILL NEED TO REPLACE SENSOR AND UPDATED WIRING HARNESS. DOES HAVE UPDATED GASKETS FOR INTAKE. TSB #02-06-04023A"

They quoted me a cost of $850 for this repair. I can't afford that after just buying this truck. The truck runs very smooth and I have not heard any pings. I know the dealer must have power washed the engine as it was spotless. I am thinking this is what set the code off after reading so many things about this online. I am by no means a mechanic, but I am wondering if this is something I should try to repair myself. I have only done the basics when it comes to auto repair-oil changes and replaced a motor in a window. Am I crazy to think I could do this? I just can't see paying that much for it when I know the parts are not that expensive and labor should not be that much.

Also, I read that AutoZone will check for codes and clear them so that the light will go out. Is that true?

Now, I know what most of you are thinking. Here is a female who is talking about doing something that is way beyond her abilities. Well, I am no girly-girl. I like a challenge and have repaired numerous home appliances just by researching what to do. I hate to pay someone else so much for something I can do myself. So, what are your opinions and advice. I would most likely have some help from my brothers, who also are not mechanics, but like a good challenge.

Go for it Cupcake!

absinthminded · December 30, 2011

I've been ignoring my check engine light for far to long. I will be ordering my parts soon and correcting this issue. I'm ready for better MPGs and power.

Bizill · January 21, 2012

Awww, yeah. Newbie here, but member of countless other forums. Had a service light for awhile and finally got a scanner. p0332 or what not and google led me to you fine folk. I know I'll be needing to do this. I wash my engine all the time. Maybe I got away with doing it for so long because I'm in the Tucson, AZ desert. Regardless, it needs to be done as the code keeps tripping after I clear the code.

By the way, instead of going with a cheapie single led scanner or a super-duper expensive setup, I went with an ELM327 bluetooth scanner that plugs into the aldl and use a program called Torque pro on my Android Evo 4g w/bluetooth. This set up is the damn tits! Elm327 can be had via Amazon or ebay for $20-$25ish. The Android phone, well, obviously you gotta have one.

As far as doing this service, I'm debating NOT getting the new harness unless I tear into the intake and find I need it. I have a 3rd vehicle to get me by should I need to order it. But being that it gets hot and dry enough in the desert as is, I might wanna just order it up beforehand. Perhaps the stealership has it local vs online and I can return it if I don't need it? I wonder if they rape you in price, though. Guess I'll have to call in the A.M.

Bizill · January 31, 2012

Done, and done. Did it over the weekend and as others have mentioned, I seem to have gotten power back. How much, I don't know, but I can chirp my tires once again with my automatic transmission when it up-shifts.

stahlhelm35 · February 25, 2012

Hello. Im new to the forum. I have a question and need some advice. I have a 2002 GMC Sierra 1/2 ton 4x4, 5.3l v8. My service engine light has been on for a while. I have used the OBD2 reader and it shoots out the P0332 code. Low voltage rear bank Knock Sensor. I know if the knock sensor goes bad or goofy, the milage on my pickup and other things happen to the engine. Heres the delima. The light likes to stay on for a while and then sometimes it goes off for a few days to weeks and then comes back on. Been doing this for a while. I can use the reader and turn it off and then a few days later or hours later it comes back on. I am getting 19mpg on the highway and between 14 and 16 in town. Is this light being a gremlin or is something going on and I just need to take the intake off and replace all the knock sensors and wiring? It came on right after I washed my engine. I know NOW, bad idea. I took the wiring harness connection apart, the one on the side of the intake, and there was a few drops of water in there. I dried it out and put it all back together, turned of the SES light and three days later it came back on. It just turned 141,000 miles. I use the less expensive 87 octane and Lucas fuel treatment, doesn't ping with it. What the hell do I do?

Jeb

Joshharrelson · March 3, 2012

Well, after reading all ten pages, im reviving this thread!

Im new to owning a full size truck, Always had a offroad toyota pickup that was my Daily Driver.

I was a member of a forum online Yotatech.com

Which is pretty much like this forum, except for toyotas.

Im very mechanically inclined and plan to tackle this job myself.

History; I threw a knock sensor #1 code about 2 months ago...Had it checked by Advance auto and confirmed.

I had the normal loss in gas mileage and lack of power. It takes more pedal to maintain speed than it did when the truck was running profficiantly.

I am fairly sure that when i remove the intake i will find standing water on top of the knock sensors seeing as that i bought the truck from a used car dealership and i could tell right away that the engine had been pressure washed seeing as that the sticker on the fan shroud had water underneath and had deteriorated.

Back to the history; When i first threw the code i decided to drive the truck like it was just until i got my income taxes back so i would have some money in my pocket for this job.

I was driving through town one day, with the knock sensor code still on and the engine still lacking power, rough idle, bad gas mileage etc etc.

Pulled up at a fast food joint and went in for 10 minutes or so...

When i came back out and cranked the truck up, the code was gone!

Truck ran at optimum performance and was back to itself completely...So naturally, i drove it around for a few weeks and left it alone...Why replace the sensors if maybe it was a fluke? Tax money came and went...On the way home from spending my last bit of tax money on a set of new tires, i threw the code again...It has been like this since april 27th and still no change.

Due to having to drive 120 miles back and forth to work, i will be replacing them soon.

My question is, why would it throw the code, then clear the code itself and run perfectly fine and then throw the code again?

Doesn't make sense to me...Replies are appreciated and i will keep updating on progress!

cajunsuperduty · March 3, 2012

There is a procedure on here somewhere that gives good instructions on how to do a good seal and water barrier with silicon when reassembling the knock sensors. The rear foam rubber seal on the rear underside of the manifold definately needs to be removed as it only traps water and dirt and does not water to drain out of the rear of the underside of the intake. This was evident when I did my knock sensors on my 2002 Yukon. You can also place a bead of silicon to act as a water levee/barrier to keep water running to the knock sensors when you pressure wash your engine.

ryangt · March 20, 2012

How the eff does the water get up there? I bought my truck used so i'm sure the engine was washed before I bought it, but I haven't washed the engine since. It goes through the car wash at least 4 times a week and I flew through some big puddles this week, but how does water get on top of the engine UNDER THE INTAKE MANIFOLD?!?!

Looks like I am going to pulling the intake manifold tomorrow night. UGH! Why do so many things go wrong with this truck?!

by doing stuff like this......

zedbear · April 18, 2012

Great thread.....

I'm replacing my leaking intake, valve cover, and valley cover gaskets and decided to go ahead and do the knock sensor/harness job while it's all apart. Looks like the truck was never really used for any serious mudding and/or the engine was never "overwashed" because the sensors and sensor wells were almost pristine and it appears to be all original. Hated to spend a lot of money on something that's probably not defective but I hate the thought of putting it all back together and getting a knock sensor code a few months from now. I was getting occaisonal light to moderate knocking on warm days but I think it was due to an intake leak.

A few things I'm glad I found are several of the valley cover bolts were not even finger tight and that stupid coolant crossover pipe thing above it was rotting in a few places and there was signs of seepage. I put a little bending pressure on the coolant pipe and it broke right where it was rusted, just like a rotted brake line. The worst spot was where that foam pad thing at the front of the intake crossed over it. Obvious what was going on there. I will post the P/N for that pipe when I pick the new one up from the dealer tomorrow, in case anyone ever needs it.

jjkoe3 · April 28, 2012

I am getting this code as well and I will be doing the repair as soon as my parts come in. However, my inspection has been up for 2 months and I just can't wait any longer as the police are setting up their checkpoints with the warmer weather. So this is a fix for any who need their inspection right away.

I cut the two wires coming from under the manifold. If you reach around the rear of the intake where the foam is on the driver's side you should feel them. About 2 or 3 inches before they go into the harness you cut the wires. On the harness side I stripped the two wires and twisted them together. Next I used a yellow female spade connector which will allow the extra girth of two wires. I connected a blue male spade connector to the dark blue wire, which is the front knock sensor. Connect the two spade connectors and voila.

This is meant to be a temporary fix and obviously when you do the job correctly you will need the new harness but it can get you through an inspection. It worked for me.

Sir_Diesel · May 21, 2012

Guys, this thread it top notch!

I wish I would have found it before I started the R&R of my knock sensors. I would have stopped by the chevy dealer and picked up a harness. As of now I am having to put the job on hold til I get a new one.

Here's a few pics of my progress!

didjareally · August 25, 2012

Joined this forum just to say thanks to everyone who has added information in this thread. Using the info here I was able to change out my knock sensors today with somewhat ease. I have a 2001 5.3L Silverado that has had the SES light coming on for a few months. I reset the P0332 code, but within 15 miles it would come on again. I never really experienced a loss of power or mpg, however at certain RPMs it could cut out and misfire. Got everything swapped out and installed today in just over 4 hours and so far haven't had the SES light come back on, although it has only been about 50 miles of driving. I was able to get (2) AC Delco Knock Sensors for $33.03 each, a Dorman Sensor Harness for $31.57, and AC Delco Intake Manifold gaskets for $56.08. Total was $153.71 with free 2 day shipping thanks to my Amazon Prime membership. Other than that I picked up a couple cans of carb cleaner, silicone, threadlocker and was able to get this done for under $200. (even after I put my arm on one of the heater hoses and broke the hose connector coming out of the firewall DOH!) I read the different methods on here as far as removing things and decided to leave the fuel rails attached to the manifold. I already had fuel line disconnect tools so taking the fuel lines off was simple. Thanks again to everyone here that contributed their information and experiences, hopefully no more SES lights from my truck for awhile.

Dirty engine bay

My harness wasnt in bad shape looking at it from the outside but the rubber boots rattled back and forth and obviously wasn't sealing any water out. Once removed, part of the wiring to the rear sensor was broke and stayed with the sensor. The front sensor wasn't too bad either, but then again I wasn't having problems with it. Regardless they both got changed while I was in there, as well as the harness. The rear one however, well........

Finally, all cleaned up and ready to put back together

slammed02chevy · September 7, 2012

Gentlemen,

I'm hoping to get some feedback from everyone's experience on this subject. So I've had the 0332 code for some time now and probably a year and a half ago I actually pulled the whole thing apart and replaced the knock sensors. Mine looked basically exactly like all of your postings with a heavily rusted knock sensor. The wiring harness looked pretty well intact though with no visible issues of any kind. I have definitely been a guy guilty of cleaning the engine though. I've cleaned my engine bay throughout the entire life of my truck... I'm a bit of a custom truck guy. My engine bay is cleaner than most people's exterior. Here is a pic for the curious (pay no attention to the ladies lol)...

ANYWAY, so I replaced the sensors and things never went away. To be open about everything, I didn't have a torque wrench so I snugged the rear (or whichever bank the P0332 was) down hand tight. I used the sealing method around the gasket. I even re-tried it a half a year later or so and pulled things apart and then replaced the front as well, tightened and sealed them. Again, no specified torquing. Still nothing. Frustrated as shit still, I have given up. I have read that it's possible the ECU could go bad which I really hope it's not. I don't want to take things apart again, but I don't know how to test if the ECU is bad or if I got a bad sensor or something from the start.

I'm considering handing it off to a dealership and just paying up for them to fix it, but I'm afraid they'll do one of those replace 1 thing and I pay for it, then they say "oh that wasn't it, we have to also replace this..." and next thing you know I have a $1,000 repair just to turn off a damn light that does NOTHING except force me to try to find "alternative methods" for getting my truck to pass state inspection.

Does anyone have input for me? Also, a VERY important question I don't know the answer to is this... If my engine has a loose rocker or something to that effect that could cause knocking... would that make this light come on? I'm wondering if I actually have some sort of problem with my engine itself that isn't allowing these sensors to function properly because it's something beyond a simple advance or retard of the timing that the knock sensors control. I suggest this because I have something similar to the cold start knock except I don't see the knocking going on just when its cold. In fact, I don't have much knock when it's cold. What I find happening is more than once it's warm and I've driven for a bit, when I lean on the gas to the point to where I'm at full acceleration BUT without downshifting (so I'm staying in the same gear, just pumping more fuel to force acceleration), I start hearing a "ticking" sound. It's prominent enough to hear, but I wouldn't describe it as a "knock" it sounds very light. This is why I'm thinking maybe a rocker?? When I accelerate hard and downshift I do not hear it. When I let off the gas and cruise, I do not hear it. It's only under full acceleration without a downshift. And it doesn't happen ALWAYS, but it will happen most of the time when the engine is already warmed up.

I appreciate any help/suggestions you guys have to solve this damned mystery.