Knock Sensors Chevrolet 5.3

[krismoriah72]

I bought a 2002 Suburban with a 5.3 knowing that it had knock sensor codes. Low voltage on both sensors according to my scanner. I replaced both sensors and wiring harnesses along with new felpro intake gaskets. Under 100 miles later codes came back. I have cleared the codes several times and keep getting the same ones back.. In my head i want to rule out that i got two bad sensors..and dont want to do the job again and get the same results..

I have done some reading and it may be possible that carbon on the piston crowns is causing this..but there is isnt a ton of info relating to this except for 'seafoam it'..the more techy forums recommend the GM upper

Truck runs great, not pinging on loads or hills. Gas mileage is good for what it is 14-16 mpg in mixed driving.

Ignore light? Redo with different sensors? Try a carbon cleanup?

 

[nwjones18]

I've been fighting Knock sensor problems on a 1997 Saturn ever since I got it. Only thing that has done any good is seafoaming the intake.. I can still feel the sluggishness sometimes but its never severe enough to set a code (after seafoaming). Know this isn't anything like your vehicle just my experience.

 

[PolarisX]

Check the harness going to each sensor.

 

[Hokiefyd]

To my understanding, a knock sensor code in the computer is generally a communication or a response problem with the sensor itself. Such as, the signal is always high, always low, etc. I wouldn't expect that other factors (like piston carbon) could influence that.

OP, what is the actual Pxxxx code?

 

[krismoriah72]

Originally Posted By: Hokiefyd
To my understanding, a knock sensor code in the computer is generally a communication or a response problem with the sensor itself. Such as, the signal is always high, always low, etc. I wouldn't expect that other factors (like piston carbon) could influence that.

OP, what is the actual Pxxxx code?


P0332 P0327

 

[Olas]

Use the highest octane fuel available along with redline si1, and change the coolant and thermostat. If that doesn't make any difference ignore the CEL.

 

[Ramblejam]

Originally Posted By: krismoriah72
Redo with different sensors?


Did you use 116 sensors (part number)?

 

[krismoriah72]

Originally Posted By: Ramblejam
Originally Posted By: krismoriah72
Redo with different sensors?


Did you use 116 sensors (part number)?


Borg Warner 8696 which crosses to your 116 number.

I should have used the 113?

 

[Virtus_Probi]

Originally Posted By: Olas
Use the highest octane fuel available along with redline si1, and change the coolant and thermostat. If that doesn't make any difference ignore the CEL.


I wish I could just ignore CELs, at least for a little while...last time I got one, the limp mode it went into including disabling the turbo. Kind of hard to miss that!
I honestly can't recall exactly, but I don't remember that happening when I was throwing codes for a software problem Subaru had just after I bought the car. I felt like a Michigan truck fully loaded with steel could have blown me away off the line when that little 2.0l was trying to pull my SUV around without some boost to help out.

Based on what little I know, a knock sensor railing would have to be due to a bad sensor, a connection problem, or maybe some interface electronics between the sensor and the uprocessor getting fried. I think the ECU module would have to be changed to fix the last case...

 

[Hokiefyd]

Originally Posted By: krismoriah72
P0332 P0327


P0327 = Knock Sensor 1 Circuit Low Input

P0332 = Knock Sensor 2 Circuit Low Input

These, together, would have me double- and triple-checking the wiring, and potentially looking at the computer as a possible issue. It sure seems like the circuit is "dead" somehow, and the computer's sensing that. Maybe it's a bad computer, but I think it's likely that there's an electrical issue that is causing this.

 

[440Magnum]

Originally Posted By: Olas
Use the highest octane fuel available along with redline si1, and change the coolant and thermostat. If that doesn't make any difference ignore the CEL.


Octane has nothing to do with knock sensor error codes. If the engine is knocking and the sensor detects it, it will not throw an error. An error means that either the sensor is open (no continuity detected by the computer) or is not getting power from the computer.

As others have said- wiring, or the power supply in the computer that feeds the knock sensors is the most likely culprit. Since re-wiring and changing sensors kept it away for a while, my bet is on a bad connector pin or socket somewhere.

 

[supton]

Originally Posted By: Olas
Use the highest octane fuel available along with redline si1, and change the coolant and thermostat. If that doesn't make any difference ignore the CEL.


Depends upon where he lives in New England. If he's in NH that's a no go. Eventually it has to be fixed in order to pass state inspection, or it's illegal to drive. Dunno about VT, RI; Maine one can just clear the code and pass, right before going in. CT and MA I think is like NH.

 

[Ramblejam]

Confirmed my suspicions: 8696/116 are the same part in a different box, and sometimes don't work well. Use OEM only, ACDelco 213-3521. Around $45 on either RockAuto or Amazon.

 

[krismoriah72]

Originally Posted By: Ramblejam
Confirmed my suspicions: 8696/116 are the same part in a different box, and sometimes don't work well. Use OEM only, ACDelco 213-3521. Around $45 on either RockAuto or Amazon.


Im with u sort of. I have read a few posts where guys re-did the job using ACDelco parts and ended up with the same results. Also posts where they re-did with ACDelco parts and solved the problem..

Im questioning parts/torque etc..but i find it odd that i started out with two codes for bad sensors, replaced both and got same codes... i saw one post about a ground to the PCM on the back of the block that fixed one guys problems and another with MAF sensor causing it..

If this were a customers car i would be in trouble right now having to possibly re-do the job and get the same results with different parts...thats what has me stumped.

 

[Ramblejam]

You've done basic troubleshooting (multimeter on PCM to jumper harness, then harness to connector), right?

The sensors you have in there now will test fine (93-107 ohm), but still throw a code.

 

[krismoriah72]

Originally Posted By: Ramblejam
You've done basic troubleshooting (multimeter on PCM to jumper harness, then harness to connector), right?

The sensors you have in there now will test fine (93-107 ohm), but still throw a code.


no i didnt. The old sensors were in such bad shape I thought it was a no brainer for a sensor swap.

 

[01rangerxl]

Originally Posted By: krismoriah72
Originally Posted By: Ramblejam
You've done basic troubleshooting (multimeter on PCM to jumper harness, then harness to connector), right?

The sensors you have in there now will test fine (93-107 ohm), but still throw a code.


no i didnt. The old sensors were in such bad shape I thought it was a no brainer for a sensor swap.


It was a no brainer, but some aftermarket parts are just flaky. I'd go with OE for something like this. Take a very close look at the harness.

The knock sensors can rust out from water and dirt collecting around them. You should seal off the harness plugs with silicone to keep water out.

 

[Olas]

Map the function out, or go to motech/lynx/dta etc etc and have it run just the way you want.

 

[ls1mike]

On my 6.0 truck I had almost the same problem. When I changed the sensors I did not us GM stuff. I used the Borg Warner ones. I also changed out the harness. Code was gone for a little bit then it returned.
Tried the Seafoam solution. No change.

Finally broke down took it to the dealer they scanned it and drove it. I explained to them what I had done.
The said "They have seen this particular problem before with the aftermarket knock sensors"

They did not charge me for the diagnosis which was nice. I went over to the parts counter and picked up the OEM ones. Installed them and the code was gone. That was 5 years ago.

 

[ls1mike]

I might add I did all the trouble shooting. Checked the sensors, harness, and the rest of the wiring associated with the circuit. All Checked out.

That was why I finally took it to the dealer.

Just go with the OEM sensors in this situation.