knock sensor codes??
Thread Starter
Intermediate
Joined: Apr 2011
Posts: 30
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From: Louisiana/Texas
knock sensor codes??
My stock '02 LS1 is throwing a couple of codes.
PCM P0327 H C
PCM P0332 H C
According to another thread here this indicates front and rear knock sensors? The engine is running perfectly, I hate to tear into it right away but I can if need be.
Any advice welcome
PCM P0327 H C
PCM P0332 H C
According to another thread here this indicates front and rear knock sensors? The engine is running perfectly, I hate to tear into it right away but I can if need be.
Any advice welcome
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
These are LOW frequency codes--- although they are shown as bank 1 and bank 2--they are actually front and back--Could be a result of several things--1st i would check to see if they are "real" or "false" codes---This can be done with a full tuner/data logger or with a better scanner that will show actual timing---For example if your ECM is asking for 25* at a certain time and your data logger shows only an actual timing of 20* (just a basic test as timing can also be removed by high IAT and ECT temps--so do this test when the car is cold) you are losing timimg most likey from the sensors-This would show that it's a real code--If there is No change from actual to the commanded then it can be a false code
False codes can be caused by several things--Most common are
1. bad Knock sensors
2. Mods such as LT headers--any change in the exh system-noisy valve train-noisy injectors
You can "tune out" false codes with a full tuner
If in fact the codes are real--- and you DON'T hear any pinging/knock-- then you can de-sensitze the kncok sensors to not pick up new noises from mods as listed above
False codes can be caused by several things--Most common are
1. bad Knock sensors
2. Mods such as LT headers--any change in the exh system-noisy valve train-noisy injectors
You can "tune out" false codes with a full tuner
If in fact the codes are real--- and you DON'T hear any pinging/knock-- then you can de-sensitze the kncok sensors to not pick up new noises from mods as listed above
Thread Starter
Intermediate
Joined: Apr 2011
Posts: 30
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From: Louisiana/Texas
Thank you sir, I did some reading on a LS1 site and spoke with a local mechanic. He said to reset the codes then have a full diagnostic ran by a GM dealer if they trip again. The car had some old e10 fuel in it and I was going up a bumpy bridge when the CEL came on. I also think I may have a slightly loose exhaust bracket near the rear of the car.
I fueled up with some non-E & may seafoam, and will reset them and cross my fingers.
I fueled up with some non-E & may seafoam, and will reset them and cross my fingers.
Last edited by Downtimela; Apr 26, 2011 at 11:25 AM.
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
ALSO --a little known fact--Your knock sensors send kncok signals to your ECM--the ECM records "occurances of knock " when it counts to a predetermined # it switches to your "low octane spark table"--To get the ECM to return to the "Hi-Octane spark table"--you must fill the car with at least 10 gallons of fuel---GM does this so the ECM can adjust and protect the engine for a 'bad tank of gas"-water in fuel or something similar
Many tuners copy the hi table into the low for this reason in a performance application--
Many tuners copy the hi table into the low for this reason in a performance application--
Thread Starter
Intermediate
Joined: Apr 2011
Posts: 30
Likes: 0
From: Louisiana/Texas
I reset the pcm codes, tanked up with good fuel and some seafoam and drove it for 40 miles. No knock or anything, check engine light hasn't came on.
hopefully it was a false code
hopefully it was a false code
Thread Starter
Intermediate
Joined: Apr 2011
Posts: 30
Likes: 0
From: Louisiana/Texas
the two knock codes only come on now under fairly hard extended acceleration, not during everyday driving use....does this mean they are probably false??
I'm not feeling any miss/knock at all when they trip....too sensitive????
I'm not feeling any miss/knock at all when they trip....too sensitive????
