tinbender59

any luck?

cooter26

I had the same problem, when i tested them for resistance after replacing both they were good, then i found an other test that you beat on the block with the engine off to simulate a knock and see if the sensors are working, the back showd a good range and the front did not. So i bought a brand new bad sensor apparently. When i replace it this time i will do both test on the sensors before i put the intake back on.

slammed02chevy

Does anyone in this thread have more details about diagnosing this problem? Like specifically resistance readings and voltage readings at key places. I have pulled my intake manifold 3 times trying to correct my original P0332 error. I originally replaced just the rear, then re-pulled it after I was still getting the code and replaced the front and the wiring harness. I'm now getting both the P0332 code and the P0327 code. With much frustration, I attempted to trick the system by using the old wiring harness clip and two 100 ohm resistors in line to a ground on the fire wall. This gave me the 100 ohm resistance needed for spec from what I seemed to find online. It didn't work. The thing I didn't think about though was that in order to ACTUALLY trick the system, it would also need to provide some sort of voltage feedback? Is that correct or does it ONLY provide voltage back to the PCM when it detects a ping?

I'm trying to avoid pulling this thing AGAIN to only have it not work. I would like to diagnose the problem as best as possible before doing any heavy work. I hear it can also be a bad PCM, but no one really says how to test this aspect? I'm not even sure I have all the right tools for the job to do it myself, but if I could have some sort of certainty I would feel better taking it to a mechanic if I have to. I'm picturing taking it to a mechanic now who will charge me to do the Knock Sensor replacements and maybe even another new wiring harness only to discover it's still not working, Then charge me to replace the PCM... then hoping that works.

As mentioned I've replaced both Knock Sensors (I didn't have a torque wrench when I did it so I just snugged them down hand tight too...) and the wiring harness. When I pull the clips apart and OHM the wiring running to the Knock sensors I'm getting 1 reading OL (open sensor) and the other is right about 100 as would appear to be correct. The weird thing though is that I am still getting BOTH knock sensor faults showing in my Service Engine readings.

My truck actually runs completely fine too. Gas mileage is normal (which of course is still bad at a wopping 17 mpg's... then again I have 22 inch rims on my truck too). I do have an occasional sound coming from the engine under load. It seems to occur more after it's warmed up and when I'm in a high gear and accelerating. If the engine downshifts the knocking doesn't occur... only during heavy gas and high gears. I'm not even certain it's actual engine knock because it only does it when I drive. I can't re-produce it sitting still revving and it really does sound quite light and "ticky" if you catch what I mean. It's almost a fast ticking sound. Oh and it doesn't appear to speed up in the number of ticks as vehicle speed increases, but then again I suppose engine RPM's aren't changing rapidly either considering it won't do it if I give it enough gas to downshift.

Anyway I'm desperate here for some sort of answer on this thing that would be more solid. Is torquing super important? Do you think I was having grounding issues with the KS themselves when I tightened them? Is it likely these things are/were bad already? What can I do to make certain before pulling everything apart again that the problem does in fact lie with the KS? Anyway have an idea what voltage readout should be when the truck is running?

slammed02chevy

What was that range you tested on them? I would like to test this as well...

cooter26

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Disconnect knock sensor harness connector. Using an ohmmeter, measure knock sensor resistance between sensor terminal and engine block. Resistance should be 3300-4500 ohms. Connect DVOM between sensor terminal and ground. Set voltmeter to 2-volt AC scale. Start and idle engine. Tap on engine block near sensor. A signal should be indicated on voltmeter. If no signal is indicated, replace knock sensor.

rodski736

Im haveing the same problem with my 2000 gmc 1500 5.3L pluged it in to scan and said about 4 cat codes cuz i have not cats the guy i got it from did that and its saying knock sensor bank 1 low volts and miss fire so i checked for power at plug it said 0.03 on bolth and aright around the same when i tested the knock sensors buy tapin on the alt bracket it seems to have a ruff idle like its camd a bit no problems with take off seems like good respose and also when i fire it up once and a while it will frie up and die then start it a gen and almost dies but then seems to pick up idle theres 145.000 on truck

Madison Made

I purchased a 00 Tahoe that had 150k on it...Owner let it go to **** by not doing regular maintenance. He informed me it takes a couple key turns to start and it has a knock sensor code that's being thrown by the PCM..So I bought it and started to do what I do..Bring back **** cars .So I'm doing the full tune up fluids,filters,wires ,plugs,so when I get to the #8 plug , pull it,to my surprise it was the original plug from 17 years ago, all 7 were modern looking NGK plugs, this plug look like it came from the 70s ..old autolite plug ..So that had me scratching my head like WTF..Finish tune up and stsrted to trace the source of the hard start ..Traced it to the fuel regulator.. Replaced it..Truck starts right up..Clear knock sensor code and it hasn't been back since..The dumb as who had the truck before obviously couldn't figure out what the problem was so he decided to drill the check engine light off..They sent a drill stright threw the cluster to bust the check engine light bulb 😂😂😂😂😂..WHAT A LAZY PIECE OF ****..Anyway.. so now the truck has a code for the check engine light being out I get it scanned every couple of months and that's the only cold it throws ..now debating on whether I should go to the junkyard and spend 40 bucks on a cluster or just leave it be..Don't know if that was the reason the knock sensor code was being thrown but hey it cleared mine..Hope it helps

Tom Dixon

I bought a 2004 Burb 5.3L about 5 years ago. It only had 50K on it. Some issues with the carbon filter, and then the Rear Knock Sensor. Had the knock sensor replaced, and no light again for about a year. The mechanic said he had an upgrade which consisted of telling them to seal the knock sensor covers with silicone, but I thought WTH, give it a try, but the insurance wouldn't pay for a second knock sensor replacement, so I had to pay. It ran nicely for about 20K miles, and then it started again. So for about 30K miles I've been letting the light show. I have the interface and App for my iPhone so I turn off the light whenever inspection is due. Make a long story short, the burb runs fine, I drive it everywhere with the light on. Just check it every once in a while to make sure it is just the Rear Knock Sensor and not something new. I think Chevy should have to pay for this engineering blunder, really.

ncrrolfe

The P0332 that I am getting with my 2001 4.8l Silverado is low output from the rear sensor. According to Haynes Repair Manual: The sensor generates a voltage with normal smooth running engine. A rough engine would generate a higher excessive voltage, that would be seen by the PCM and in turn and reduce knock during periods of heavy detonation. Using Haynes troubleshooting technique, I located the wiring harness as shown in Haynes pictures. I open the connector and measured the resistance to the good ground. For a ground connection my truck has flat braided wire at the firewall nearby for easy connection. I found the Dark Blue wire had 100K ohms of resistance to ground while the Light Blue was open. Then checking the Haynes wiring diagrams for the Engine Control System it shows that the Light Blue wire connects to Rear Knock Sensor and is in agreement with the P0332 code. While I haven't replaced it yet it does indicate the sensor is bad, but could be a broken wire between the sensor and the connector. What I plan to do is replace the sensor and verify that 100K ohms is indicated before I put everything back together.

Mr.Breeze

Listen up, you all having problems with knock sensors, AC Delco knock sensors was the answer to the problem on my 2000 Chevy Silverado 5.3L 1500 with 171000 miles. The computer does not recognize aftermarket sensors.The aftermarket knock sensors did perform,the computer doesn't recognize that.so the check engine light comes on.and the code for low current will stay.No need for new ECM.if you do replace ECM, be sure to it matches GM, like ACDelco.an aftermarket ECM will probably give your truck allot of problems that you don't want.Hope this was helpful,