What is the knock sensor function for - Cars & Trucks

The knock sensor is located on the engine block, cylinder head or intake manifold. This is because its function is to sense vibrations caused by engine knock or detonation. The PCM uses this signal to alter the ignition timing and prevent detonation.

The 4.3-liter's sensor is on the right cylinder head, beneath the rear of the exhaust manifold.

https://itstillruns.com/knock-sensor-43-vortec-engine-7911114.html

You need a full function scan tool to read the output of the knock sensor while you drive it under different throttle settings and loading. There is no real way to "bench" test the sensor. The reason is that the sensor is an output device called a "Piezo Electric" sensor, it vibrates a tiny ceramic disk during engine knock and sends out a low voltage signal to the engine control computer when a knock is detected, so in order for the output to be tested you need it working on a live engine..

What type of. vehicle? The knock sensor may be functioning properly and is picking up a knock from the vehicles engine. Sometimes a low grade of fuel can cause the engine to ping resulting in a knock sensor code. Is there any abnormal noises being produced from the engine or bolt on accessories?

Hi. The function of thie knock sensor is to sense vibrations caused by engine knock caused by pre-ignition. The PCM uses this signal to alter the ignition timing and prevent detonation or ping. If a ping is sensed it will slow the timing to protect the engine from this damaging pre-ignition.

thanks, that helps. It could be that is the only problem. The knock sensors started being installed several years back to provide performance feed back to the ECM/PCM. If a cylinder doesn't fire the knock sensor reports a misfire to the computer and a misfire code is shown. In this event the sensor is returning a value that indicated to the computer it was not functioning correctly. Replacement of this sensor doesn't require the motor to be rebuilt should cost around $200 at a dealer maybe a little more. You can view the knock sensor a little like the O2 sensor with the main difference being that if the knock sensor doesn't work correctly it could cause the vehicle to computer to adjust your timing the wrong way.

The 43 is the knock sensor, the wires must be broken or fused together to continue to get the same code.
Testing the sensor for the DIY Knock sensors detect detonation ( knocking ) by reacting to the ping by retarding the ignition timing so you will need a timing light for this. connect the timing light and locate the knock sensor, ( many are on the intake manifold ) now use a metal object to tap ( not too hard and not on the sensor itself ) on the intake manifold ( light tapping should suffice ), if the sensor is functioning you will see the timing ******. If the timing does not ****** you will need to check voltage across the terminals of the knock sensor connector.
Though that excerpt says your sensor is in the intake,I believe yours is in the water drain hole for the engine block.
I also found that most shops are to replace the wire to the knock sensor because of so much failure of those wires because of heat.
Enough information?Repost if this doesn't help and we can look at some other things to try.

It's located deep in the valley! Under the "LOWER intake manifold". copy and paste this link in your browser, or try clicking on it. It may be helpful to you.

http://x.nissanhelp.com/forums/pathfinder/7890-3-3l-knock-sensor-relocation.html

I didn't find this link until after I had already disassembled my truck. This is the hardest job that I've taken on thus far, hope I can put it all back together properly. I changed the gaskets on the valve covers since I had everything off.
To answer your question: It's under your lower intake manifold, so it's a hard job!

When a knock is detected, it sends this information to the computor, in which retards the ignition timing. If the sensor is bad, it will do this more often than not.

the knock sensor is located near the bottom of the engine block, it is screwed into the blocks water jacket, so make sure u drain the radiator before u change it, also it must be torqued to a specific value or it will not function correctly.