Knock sensor failure
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Joined: Mar 2009
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From: Killarny MB
Knock sensor failure
Maybe this should be in Tech but I would like to get some answers today and I don't know how frequented the tech section is. Mods, move this thread if you like.
Anyway, on to the question. My car started to throw PCM P0327 H C which is the front knock sensor circuit.
My question is for people that actually know what the engine/timing/computer does and please refrain from making guesses (unless you really want to
):
Could I damage my car by driving it? I would hope that once the computer senses a failure in the knock sensor circuit that it just retards the timing to protect the engine in case of knock now that it can't sense it. I am using premium fuel and the weather is cold. I am not putting the engine under maximum load so the chances of detonation is unlikely I assume, however, maybe the computer does not perform this function. I do not know, that is why I am asking for people who know this stuff to answer.
I want to wait until spring to fix it so I can save up for an intake since I'll be removing the intake and like to minimize the number of times I take things off and on.
As always, I really appreciate your answers.
Anyway, on to the question. My car started to throw PCM P0327 H C which is the front knock sensor circuit.
My question is for people that actually know what the engine/timing/computer does and please refrain from making guesses (unless you really want to
):Could I damage my car by driving it? I would hope that once the computer senses a failure in the knock sensor circuit that it just retards the timing to protect the engine in case of knock now that it can't sense it. I am using premium fuel and the weather is cold. I am not putting the engine under maximum load so the chances of detonation is unlikely I assume, however, maybe the computer does not perform this function. I do not know, that is why I am asking for people who know this stuff to answer.
I want to wait until spring to fix it so I can save up for an intake since I'll be removing the intake and like to minimize the number of times I take things off and on.
As always, I really appreciate your answers.
Last edited by ChromeC5; Oct 21, 2011 at 10:53 AM.
Tech Contributor
Joined: Aug 2008
Posts: 2,902
Likes: 21
From: Oak Hill Virginia
Maybe this should be in Tech but I would like to get some answers today and I don't know how frequented the tech section is. Mods, move this thread if you like.
Anyway, on to the question. My car started to throw PCM P0327 H C which is the front knock sensor circuit.
My question is for people that actually know what the engine/timing/computer does and please refrain from making guesses (unless you really want to):
Could I damage my car by driving it? I would hope that once the computer senses a failure in the knock sensor circuit that it just retards the timing to protect the engine in case of knock now that it can't sense it. I am using premium fuel and the weather is cold. I am not putting the engine under maximum load so the chances of detonation is unlikely I assume, however, maybe the computer does not perform this function. I do not know, that is why I am asking for people who know this stuff to answer.
I want to wait until spring to fix it so I can save up for an intake since I'll be removing the intake and like to minimize the number of times I take things off and on.
As always, I really appreciate your answers.
Anyway, on to the question. My car started to throw PCM P0327 H C which is the front knock sensor circuit.
My question is for people that actually know what the engine/timing/computer does and please refrain from making guesses (unless you really want to
):Could I damage my car by driving it? I would hope that once the computer senses a failure in the knock sensor circuit that it just retards the timing to protect the engine in case of knock now that it can't sense it. I am using premium fuel and the weather is cold. I am not putting the engine under maximum load so the chances of detonation is unlikely I assume, however, maybe the computer does not perform this function. I do not know, that is why I am asking for people who know this stuff to answer.
I want to wait until spring to fix it so I can save up for an intake since I'll be removing the intake and like to minimize the number of times I take things off and on.
As always, I really appreciate your answers.
Also, pulling the manifold is a pretty easy task as is replacing the sensor/examining the connections/applying rtv... why wait? You aren't going to hurt anything by pulling it more than once...
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Joined: Mar 2009
Posts: 605
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From: Killarny MB
Search is my friend! I forgot in my haste to post the thread 
but 99% of the time, I do the search.
Thank you for the link. I'll be referring to that when doing the R&R and extending the vacuum hose. The reason for not doing the job now is a lack of a garage and I want to get the car to storage. If I take it apart and run into problems, I don't want the car sitting and risking having it miss my storage deadline.
but 99% of the time, I do the search.Thank you for the link. I'll be referring to that when doing the R&R and extending the vacuum hose. The reason for not doing the job now is a lack of a garage and I want to get the car to storage. If I take it apart and run into problems, I don't want the car sitting and risking having it miss my storage deadline.
Last edited by ChromeC5; Oct 21, 2011 at 01:34 PM.
Burning Brakes
Joined: Jan 2011
Posts: 1,062
Likes: 291
From: Allyn WA
Knock sensor
I had the same problem with the rear one! The car did nothing but I do not get high into the RMP range of the car and that may be when the computer impacts the engine performance for safety. I agree with your plan but would do sooner rather than later, just because of the weather. Get it done now and one less thing to worry about! I went from an LS1 intake to a LS6 and while doing this ran into rotted PVC fittings which I am sure you will also and instead of paying over 100 bucks for this stuff decided to change out the valley pan and rid the car of the hoses, easy mod! I got a catch can to boot and had the throttle body bored and polished (also cheap) and installed 2 new knock sensors. Also, of note 2 big things to watch out for (which did not happen to me but some guys have not had a good day with these)first is the oil sensor in the rear (if not careful you can break it during the intake removal) and torques (the intake bolts are inch lbs not foot lbs) anyway read the threads on remove/install it can all be done in a afternoon if all parts and instructions understood. I had alot of fun fixing this problem and was very satisfied with the end results. Good luck!
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Joined: Mar 2009
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From: Killarny MB
Awesome. Good reply. I have a Z06 intake with the different Valley on order from a friend who fixes these cars and once he has all the parts gathered, he will be shipping them out. Thank you for the reminder on the torque specs. I will be following my service manual diligently.
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Joined: Mar 2009
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From: Killarny MB
Called the dealership, which I should have done a while ago but they usually don't know anything and want to look at it. However, I was told if you have a faulty knock sensor, you can ruin your cats and o2 sensors as the timing will be changed which affects the combustion process. The knock sensor CAN also be used as a crank sensor. He didn't that it was in this case but a faulty knock sensor can lead to a hard starting condition when the car is warm. Good to know nothing should be damaged, just that over time it can foul certain components.
