Knock sensor

[S133LTR]

Can anyone help me with information about testing/checking a knock sensor?

Is there a way I can test it out of the car/harness?

Any info would be appricated.

[DrNick]

It is just a small microphone after all. From memory you need an osciliscope to tell if the output is in the correct frequency etc. But as a quick check to see if its completely broken or not you could just try tapping it and see if you get a minute voltage coming out of it.
I dont know how realistic that test would be though because it is chosen for a particular engine block design so it might not resonate properly if its out of the car.

[S133LTR]

Thanx for that info all the same man.
The cars ECU is showing LED codes for a 'knock sensor manlfunction' but I wanted to make sure the one I have is broken before I pay over $250 for a new one.

[matt_2jzs13]

if testing it doesnt work, you can borrow one of mine and see if it does the same

[S133LTR]

Thanks Mat but its on my daily.

[2jzlux]

It could also be the wiring from the ecu to the knock sensor could be broken and it will bring up the same code.
Knock sensors arent that common to fail, usually the wiring goes first.

[Riggs]

Pull it out and check it visually too. Had one that split a while back, kept the car in limp mode.

[RRob]

What car?

The sensor wasn't loose was it?

[S133LTR]

VG30E
sensor cant be inspected without removing intake manifold, was rusted badly underneith, replaced it, didnt rectify the problem.