Check eng soon light came on. Diagnosed as knock sensor fault. What does it do and how serious is it?
2002 1500 Silverado
Thanks in advance, Richard B

 

The knock sensor listens to the engine and when it detects that the engine is knocking due to various reasons, (mainly octane level in the fuel, and ignition timing) it sends a signal to the ECM which adjusts the timing to prevent the knock.

A faulty knock sensor can affect the engine power and fuel efficiency.

 

I have a G30 RV that also had the code. I could reset it and then it would come back after a few minutes. A new sensor made no difference. Turned out to be the control module. It's a box about the size of a cigarette pack next to the throttle body on my 90 GMC 5.7 and it is part of the ECU in my 95 7.4 Chevy RV. Not sure of how to diagnose it other than trying a known good part. I ended up buying a used ECU online for $30. Just used the original chip because the used one was from a 5.7 instead of a 7.4. I guess what I'm saying is, if you can find a donor sensor to try, it might save you a wasted part. Electronics are not usually returnable.

 

Knock sensor, more than likely the far back one on the block. They get wet and tend to mess up. Gotta pull the intake off to get to them

 

Like the others said it basically monitors the firing of each cylinder and adjusts the performance of the engine accordingly.

I replaced both of my knock sensors (I figured out much later that I apparently kept getting one bad "new" sensor after another even though they were new in the box). I kept getting the DTC for the knock sensors.......So after replacing both sensors 3 different times, I finally did an ohms test on the knock sensors after the motor was hot. (apparently one of my sensors would only fail when it got hot) *When the sensors were cold they would test perfectly within range.*

So I'm guessing the guy at the parts store couldn't believe the sensors could be going bad that often so he must have been running a bench test on the sensor in the store and then restocking the bad sensor after it tested ok.....or they simply restocked the bad part by accident.....either way it was very frustrating and time consuming, but now all is going good!

The knock sensors can be damaged by a simple drop on the garage floor (but may still appear undamaged on the outside) so dont drop them

Below is from another member of the forum. It tells how to do the ohms test on the sensor. I used it and it helped me! (I ran the test several times when the motor was cold and hot) Good luck!

 

Do a search in the forum for knock sensor, some folks have had success replacing the sensor on the 5.3 without having to remove the intake... it takes a whole lot of patients and some dexterity but it can be done...

 

Suburban 2002 4x4
I have new knock sensors, about 3 months, I just change spark plugs to Bosch Platinum+4 and I am getting a P0332 code. Is this coinsidence or can this new type of spark plugs create this problem? HELP.