P0327-Knock Sensor Circuit Low Voltage
Sorry to bring up an old thread but i have been dealing with the same damn problem since before i blew my headgasket. Both BRAND NEW GM knock sensors from the dealer and harness from the dealership.. When i clear the codes the car pulls hard as hell at 12.7 AFR and 26 commanded timing but with the code on it does 12.0 AFR and 20-22 timing. I've must have had the intake manifold off 10 times already trying to fix this problem so far. I'm super close to disabling the knock sensors but unfortunately i need them.
Sorry to bring up an old thread but i have been dealing with the same damn problem since before i blew my headgasket. Both BRAND NEW GM knock sensors from the dealer and harness from the dealership.. When i clear the codes the car pulls hard as hell at 12.7 AFR and 26 commanded timing but with the code on it does 12.0 AFR and 20-22 timing. I've must have had the intake manifold off 10 times already trying to fix this problem so far. I'm super close to disabling the knock sensors but unfortunately i need them.
Its been cold here and snow on the ground so i have not had time to get the car out and do much troubleshooting on it but if you find something, please post it for myself and all others. It really seems that alot of people have this problem and never figure it out.
Just today I went through replacing my knock sensors and the harness for both! And the damn SES light came on after about 30 minutes of cruising on the interstate! I was so pissed! What the hell is up with this?? I hate having my SES light on for something that I know is just wasting my time and that I have replaced parts for. And plus if there is something else throwing a code I won't know it unless I continuously check my codes. I want this SES off and the problem fixed!
what exactly is the code you are getting? P0327? if its the knock sensor code then its more than just the ses light being on, the pcm pulls timing to protect the engine. I believe it is 4 degrees. Your car will feel like it has no power.
Check the connector and wires that go to the computer. I did find a break in the wire on mine going into the connector but i replaced it and the code still came back. I did get an aftermarket mail tune and i notice some differences in the knock settings. I am going to change them to stock and try it when the snow clears up. I have replaced everything with oem parts from the dealer.
Let us know if you find the problem.
Check the connector and wires that go to the computer. I did find a break in the wire on mine going into the connector but i replaced it and the code still came back. I did get an aftermarket mail tune and i notice some differences in the knock settings. I am going to change them to stock and try it when the snow clears up. I have replaced everything with oem parts from the dealer.
Let us know if you find the problem.
I think mine was a P0332. But I just found out the day before yesterday that my current problem is actually a Crankshaft sensor code. ?? I made a thread but i don't have a clue why I'm throwing this code. But again that's why I don't like my SES to be on constantly bc I don't know if I fixed the previous one or got a new code.
So i replaced the knock sensors and the harness and the wire from the PCM to the harness, even put new pins in the PCM connector that I got from the GM dealer. Oh and by the way, i replaced the PCM as well.
I am still getting P0327 knock sensor circuit low voltage. I followed the instructions in the following site. http://www.gearchatter.com/viewtopic9031.php
I am out of ideas.
Does anyone know what the voltage is supose to be????? What is the minimum/maximum voltage.
I am still getting P0327 knock sensor circuit low voltage. I followed the instructions in the following site. http://www.gearchatter.com/viewtopic9031.php
I am out of ideas.
Does anyone know what the voltage is supose to be????? What is the minimum/maximum voltage.
I read that the code will active when the voltage is below .500v. I disconnected the pigtail harness and read both the sensors. While reving the engine, the i seen the voltage go up to around .400v. Is this right?
I just looked at the knock sensors. The original part number on the Knock sensor is 10456603.
The new knock sensors I have installed are 12589867.
I just looked at the knock sensors. The original part number on the Knock sensor is 10456603.
The new knock sensors I have installed are 12589867.
Last edited by 1slowbusa; Mar 23, 2013 at 03:54 PM.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo These are the readings I am getting. Let me know what you think. Can someone give me some readings off your car so I can do a compare since I cannot find any min/max numbers.
They go in the order of
bank 1 resistance
Bank 1 mv at idle
Bank 1 mv at 2000 rpm
Bank 2 resistance
Bank 2 mv at idle
Bank 2 mv at 2000 rpm
They go in the order of
bank 1 resistance
Bank 1 mv at idle
Bank 1 mv at 2000 rpm
Bank 2 resistance
Bank 2 mv at idle
Bank 2 mv at 2000 rpm
Last edited by 1slowbusa; Mar 23, 2013 at 08:05 PM.
Registered User
Joined: Mar 2013
Posts: 4
Likes: 1
I am having the exact same issue with a 5.3L Vortec 2000 Silverado. Replaced the knock sensors twice but i'm still getting the 30mV when idling and upwards of 400mV when revving (ac voltage).
Everything I've been reading says that with the harness disconnected, we should be seeing a DC voltage of around 5V when probing one of the KS lines going back to the PCM, which I am not. What about you, any DC voltage?
Everything I've been reading says that with the harness disconnected, we should be seeing a DC voltage of around 5V when probing one of the KS lines going back to the PCM, which I am not. What about you, any DC voltage?
I am having the exact same issue with a 5.3L Vortec 2000 Silverado. Replaced the knock sensors twice but i'm still getting the 30mV when idling and upwards of 400mV when revving (ac voltage).
Everything I've been reading says that with the harness disconnected, we should be seeing a DC voltage of around 5V when probing one of the KS lines going back to the PCM, which I am not. What about you, any DC voltage?
Everything I've been reading says that with the harness disconnected, we should be seeing a DC voltage of around 5V when probing one of the KS lines going back to the PCM, which I am not. What about you, any DC voltage?
Last edited by 1slowbusa; Mar 27, 2013 at 01:54 PM.
Registered User
Joined: Mar 2013
Posts: 4
Likes: 1
Also just from calling a few dealers and having them read me the page out of the FSM. It is saying 5V when harness in unplugged and 2.5V when backprobing the connected harness.
I just made a 5V regulator and ran a 47k Ohm resistor to each sensor to give it that DC offset, we'll see what happens. We should probably keep eachother posted
I chased this same exact issue for a few months I replaced sensor's wiring harness etc. I ended up swapping buying a new sensor and swapping num1 and num2 and it went away and has not returned. I know its a pain to pull the intake and the sensors are very expensive so I would at least try and swap them and see what happens.
Basically any generic knock sensor testing tutorial assumes some DC voltage at the PCM, i dont have any sites off hand
Also just from calling a few dealers and having them read me the page out of the FSM. It is saying 5V when harness in unplugged and 2.5V when backprobing the connected harness.
I just made a 5V regulator and ran a 47k Ohm resistor to each sensor to give it that DC offset, we'll see what happens. We should probably keep eachother posted
Also just from calling a few dealers and having them read me the page out of the FSM. It is saying 5V when harness in unplugged and 2.5V when backprobing the connected harness.
I just made a 5V regulator and ran a 47k Ohm resistor to each sensor to give it that DC offset, we'll see what happens. We should probably keep eachother posted
Last edited by 1slowbusa; Mar 28, 2013 at 09:45 PM.
Registered User
Joined: Mar 2013
Posts: 4
Likes: 1
I unplugged the pigtail behind the intake and turn the key on and read the dc voltage from the wires of the pcm to ground seperatly and read 0V. I read the ohms of the sensors again and they are reading around 99 ohms. If i get time tomorrow I am going to swap the sensors and see if I get p0332 onstead of p0337. I will keep you posted.
I chased this same exact issue for a few months I replaced sensor's wiring harness etc. I ended up swapping buying a new sensor and swapping num1 and num2 and it went away and has not returned. I know its a pain to pull the intake and the sensors are very expensive so I would at least try and swap them and see what happens.
Im dealing with the same issue right now. Threw the code while at the track two weeks ago. After some data logging, was only getting 12* of total timing at WOT, so this issue will definitely affect performance. Ill be swapping the sensors and possibly the harness today from the LS1 sitting on the stand into to car, will report back.
I took the intake off this evening and noticed alot of oil in the head ports and in the intake.
I did some research and found a great write up regarding the crank case pressure. I still had the PCV valve installed and when I looked at it, it was covered with oil. I am going to do the PCV delete and put a breather on the driver side rear valve cover port and one on the oil filler and also put the catch can between the passenger side valve cover front port to the intake. This will hopefully let the crank case breath. This could be causing my knock sensors to go off.
http://www.ls1.com/forums/f48/pcv-ca...ressure-81389/
Let me know what you guys think.
I havent swapped the sensor yet because I want to try this first.
I did some research and found a great write up regarding the crank case pressure. I still had the PCV valve installed and when I looked at it, it was covered with oil. I am going to do the PCV delete and put a breather on the driver side rear valve cover port and one on the oil filler and also put the catch can between the passenger side valve cover front port to the intake. This will hopefully let the crank case breath. This could be causing my knock sensors to go off.
http://www.ls1.com/forums/f48/pcv-ca...ressure-81389/
Let me know what you guys think.
I havent swapped the sensor yet because I want to try this first.
Pulled the intake tonight and the front sensor (the one throwing the code) was filled with water, rust and corrosion. Took it out and it it ohmed out at 46.5k, obviously bad as its supposed to be 100k. So that's all cleaned up, swapped both sensors and harness for good measure with the ones from my old LS1, sealed both of the covers with some black RTV so we wont have this problem again. Gonna finish up tomorrow, but I have absolutely no doubts that the problem is fixed.
As far as the oil, yeah looks like typical PCV. I had a bit of oil myself but nothing horrible. I wouldn't recommend removing the PCV valve though, you need that vacuum ventilation on the crank case. Putting a catch can between the front most port on the passenger side wont do anything as that's just the fresh air port, air is pulled into that port from the other two ports attached to the PCV valve. The catch can needs to be inline between the PCV valve and the lower vacuum port on the TB.
As far as the oil, yeah looks like typical PCV. I had a bit of oil myself but nothing horrible. I wouldn't recommend removing the PCV valve though, you need that vacuum ventilation on the crank case. Putting a catch can between the front most port on the passenger side wont do anything as that's just the fresh air port, air is pulled into that port from the other two ports attached to the PCV valve. The catch can needs to be inline between the PCV valve and the lower vacuum port on the TB.