P0332 Knock Sensor 2002 Sierra..help !

[cwildkats]

Hi all.I bought a 2002 gmc sierra sle with the 5.3l about 3 weeks ago.It runs an drives excellent. This saturday the service engine soon light came on.I had auto zone use their engine code scanner an it came up the P0332 -knock sensor. I have had diferent opinions. Some told me to change it that it could ruin the motor ,some have told me if the gauges are correct an it runs fine to ignore it. Well the truck sounds perfect.It has 91k miles an i do have a power train warranty on it but i was told even though the knock sensor is under the intake its not under warranty. I was told it would be about 300.00 to fix .Im not so sure i wanna spend 300.00 just yet on something that may not cause the light to go out.I did have them clear the light an i changed the fuel filter an put in high octane fuel but 2 days later the light came back on.Im just curious,from an experts point of view,if the truck runs an sounds great is it very important to have the knock sensor changed? or is this the problem to begin with? What to do? I have seen a quaetion on here before.Someone said if the engine is frequently pressure washed it could corrode the sensor.Well the engine is spotless.Im thinking some one has had to have pressure washed this engine.Any help will be appreciated.

[longhorn_giant]

I had the knock sensor code on my '02 sliverado awhile back, but it was the 4.3 6cyl, which is a totally different animal from the 8cyl. I did a bit of research on the 2 and what I came up with for the 5.3 is that the knock sensors in your engine can go bad due to some water buildup - the sensors aren't sealed really well, and that could caues the wiring to corrode and/or the sensor to go bad.

 

Mine wasn't under the manifold, and I did just what you did - cleared the code - and it never came back on. If it came back on I'd say you might want to look into swapping them out. I don't know how do-it-yourself you are, but it's not supposed to be that difficult to swap out if you're comfortable pulling your intake manifold off.

 

My .02 would be if it's running fine, you're not feeling it knock/rev on you, then it's most likely just the sensor. I read (notice this is all "I read" and little "I did") that you could test the sensor by whacking the exhaust manifold with a rubber mallet while the engine is running. If the engine revs to dampen out the motion then the sensors are working. If you want to start knocking things around then be my guest!

[redvett]

With any knock sensor code the PCM will set the SES light and retard timing to protect the engine, the loss of performance & fuel economy will result.

[alwcurlz]

Yeah, like the guys said above. It probably has corroded contacts. It isn't too bad to get at if you are acquainted with minor engine repair. Here is a good article on the sensor locations and how to replace them. With the P0332 code, that is the rear sensor.

 

 

Audible Spark Knock (Detonation), MIL Illuminated, DTC P0332 Set (Replace Rear Bank Knock Sensor and RTV Area Around Sensor) #02-06-04-023A

Audible Spark Knock (Detonation), MIL Illuminated, DTC P0332 Set (Replace Rear Bank Knock Sensor and RTV Area Around Sensor) 1998-2002 Chevrolet Camaro, Corvette

 

1998-2002 Pontiac Firebird

 

with 5.7L Engine (VIN G -- RPO LS1)

 

1999-2002 Chevrolet Silverado, Suburban, Tahoe

 

2002 Chevrolet Avalance

 

1999-2002 GMC Sierra, Yukon, Yukon XL

 

2002 Cadillac Escalade, Escalade EXT

 

with 4.8L, 5.3L or 6.0L Engine (VINs V, T, Z, N, U -- RPOs LR4, LM7, L59, LQ9, LQ4)

 

This bulletin is being revised to add Cadillac Escalade and Cadillac Escalade EXT to the Models. Please discard Corporate Bulletin Number 02-06-04-023 (Section 6 -- Engine/Propulsion System).

 

 

 

Condition

Some customers may comment on a mild to severe engine ping (commonly referred to as spark knock), usually worse during acceleration and/or an illuminated MIL. Upon investigation, the technician may find DTC P0332 set.

 

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Cause

This condition may be the result of corrosion of the rear bank knock sensor due to water intrusion into the sensor cavity. This condition is more apparent on vehicles in which customers frequently wash the engine compartment.

 

 

Correction

 

Replace the rear bank knock sensor and build a dam (wall) around the sensor using RTV to divert water away from the sensor. Use the procedure and part number listed below.

 

 

1. Remove the intake manifold. Refer to the Intake Manifold Replacement procedure in the Engine Controls sub-section of the appropriate Service Manual.
   
   
2. Remove the wiring harness assembly from the knock sensor.
   
   
3. Remove the rear bank knock sensor.
   
4. Install the new rear bank knock sensor. Tighten Tighten the knock sensor to 20 N·m(15 lb ft).
   
5. Install the wiring harness assembly to the knock sensor.
   
   
6. Apply a bead of RTV silicone sealant approximately 9 mm (3/8 in) wide and 6 mm (1/4 in) high along the outside edge of the ridge on the engine block valley cover around the rear bank knock sensor. DO NOT form a complete circle. Leave the rear section open as shown.
   
7. From the underside of the intake manifold, completely remove the rear intake manifold seal (foam material).
   
8. Install the intake manifold. Refer to the Intake Manifold Replacement procedure in the Engine Controls sub-section of the appropriate Service Manual.
   

Parts Information

 

Part Number Description Qty

 

10456603 Sensor, Knock 1

[cwildkats]

i am having the knock sensor changed.Will timing have to be reset or will it do it on its own?thanks

[cbxeric]

After the job is done and the codes are cleared the computer will look after the rest. On my truck the rear knock sensor cover was never put on properly from the factory, it was badly corroded. The hardest part for me was the 260$ GM wanted for the new Intake manifold gaskets.

[cwildkats]

My local dealer replaced the knock sensors. The lights went out an the truck seems to be running fine.Thanks for everyones help

[alwcurlz]

My local dealer replaced the knock sensors. The lights went out an the truck seems to be running fine.Thanks for everyones help

 

We're here to help and hassle! Post a pic of your truck and come back again!

[curtishuff]

HEY CURLZ, you seem to know a lot about the knock sensor. I had the same problem with my sensor, but instead of just taking it to the dealer i decided to get my hands dirty and do-it-myself, like an idiot. So after replacing both sensors, wiring harness, and spending probably the same amount of money to let a real mechanic fix it, my truck is running worse then it was before. No engine light. But it idles up and down from 350 - 700 rpms and stalls shortly after. I keep listening for leaks and i double checked to see if the gasket and manifold were seated properly on the block, but it really runs rough now. more rough then before. Is there a way to advance the timing or something? Oh, and mine is a 2004 5.3 so there's no fuel filter to check either.

[cbxeric]

If you re-used the intake manifold gaskets they might be leaking. This could cause the idle surging problem.

[alwcurlz]

HEY CURLZ, you seem to know a lot about the knock sensor. I had the same problem with my sensor, but instead of just taking it to the dealer i decided to get my hands dirty and do-it-myself, like an idiot. So after replacing both sensors, wiring harness, and spending probably the same amount of money to let a real mechanic fix it, my truck is running worse then it was before. No engine light. But it idles up and down from 350 - 700 rpms and stalls shortly after. I keep listening for leaks and i double checked to see if the gasket and manifold were seated properly on the block, but it really runs rough now. more rough then before. Is there a way to advance the timing or something? Oh, and mine is a 2004 5.3 so there's no fuel filter to check either.

 

You don't do anything with timing on a truck that new. Everything is 100% computer controlled. Sounds like you have a massive vacuum leak somewhere. Did you put in new gaskets as well? What about the PCV hoses and PCV itself? Make sure you have all the vacuum lines attached. Sensor wires, check those too. I would say you're likely getting a stall because the system isn't able to overcome an imbalance of air/fuel. At idle speed, the motor is expecting a preset computer fed fuel/air ratio. Too much air, not enough fuel=fuel starved engine. A simple test to determine a vacuum leak on the manifold would be to partially restrict the air intake on the filter side. I'll bet the engine runs better while doing that.

Good luck!

[alwcurlz]

Just pulled off the intake to inspect/replace the knock sensors on my brother's truck. What I've discovered is that whatever is plastic/rubber is brittle after 8 years & 198,000 miles. The large black rubber plug that is inserted over the large holes is quite brittle and split. The rubber plug is not sealing at all either. It was just sitting there, rattling. When pulled out, there was all kinds of rust/dirt in the hole where the knock sensor is. The connector for the knock sensors broke as well when removing and are very brittle. I'll get some pictures later on when this is finished.

[2500sierra]

Ive got a 2000 sierra 2500 6.0l i do have the knock sensor codes, but it runs very smooth except a slight shake at idle. it gets crappy mileage and seems kinda slow, but i dont have a ses light?

 

I would like to know what the code means. Like could it mean something else is making your engine knock, or is it always a bad sensor?

 

I personally have powerwashed my engine twice, since ive owned it and its seen some mud soooo.

 

also do u always have to replace them or just clean then up?

[alwcurlz]

Well, my brother and I recently went and replaced the knock sensors and wire harness. Also replaced the intake gaskets but didn't replace the valley pan gasket.

 

Don't pressure wash your motor or you'll precipitate future problems. I think we'll be safe now, that my brother and I corrected the leaking boots. Those boots were quite stiff and so were the new ones. The connector clips were brittle and broke in pieces. The knock sensors were buried in rust/trash. There is some red dirt in the pictures on top of the valley pan and intake area but were cleaned up. The knock sensor connectors were badly rusted seen in the pictures below as well. Best to buy yourself of new set of knock sensors. My brother found a set of 2 on ebay for $40. The wire harness, GM# 12601822 was about $40 as well from the Chevy house. I would strongly recommend sealing up those grommets when re-installing them! I used the Ultra Black in a pressurized can. Worked great, and cheaper than buying two squeeze tubes for some reason! See the pictures below!

 

Here are some pictures of our process.

 

Here it is with the intake off. Note the original knock sensor harness. It goes underneath some metal tubes

and seemed a possible pinching point where it could short later on. We re-routed the new one elsewhere.

 

 

 

There is the one sensor, buried in rust barnicles.

 

Here is the one that was the culprit. See why?? Note the broken plastic pieces. Those

pieces broke off easily when trying to get the connector out.

[alwcurlz]

Here are both nasty knock sensors.

 

Note the center connector posts. They were rusted badly as well. The seals on everything was stiff with

some slop/play where it should seal so water could easily get it.

 

 

 

Here the boot is cracked some where the wire goes through.

This boot was easy to take out as it just sat there rattling in place!! The wire was loose in the hole as well.