Hello,Working on a 99 civic dx 1.6 It's throwing knock sensor no signal codes P0325 & P0330 I first replaced the sensor (under the intake manifold) if there's 2 sensors please let me know where the other is)
No change Then I ran a cheater wire from the 1 pin on the sensor directly to the corresponding KS pin on the passenger footwell engine ECU connector C ( I believe it's a red/blue wire, might be remembering that incorrectly but it's definitely connected to the KS pin) No change.Still getting the same codes which set immediately after reset I have reset ecu and cleared codes etc. Then I took a closer look at the wiring harness near the knock sensor (under the intake manifold) I discovered 1 wire which is yellow/red and it's just dangling there right near the knock sensor Anyone know what this yellow/red wire I'd or if it's related to the knock sensor codes?

 

Update.
I had initially assumed the red wire connecting to the Knock sensor got broken somewhere between the sensor and ECU.

So what I did originally was splice my cheater wire into that red wire on the sensor side, and into the red/blue wire on the ECU.
(Basically in parallel with the [assumed to be] broken connection.

This resulted in the same codes.

However, after cutting the original wiring on both yhe sensor and ECU sides, leaving only my new cheater wire, the code has not come back yet, and since it was setting immediately before, I'm assuming my knock sensor issue is resolved. The original wire must have been shorted to ground or something

I'd still like to know what the yellow/red wire coming out of the main harness, near the red wire of the knock sensor is.

It's completely disconnected just dangling there, and looks like there's some sort of copper toned crimp connection on the end of the wire.
It's hard to see up In that area without taking off the whole intake manifold which, after doing so, would likely make things much more clear.

But so for now, my question remains as to what that yellow/red wire is supposed to be connected to

 

The single yellow/red stripe wire on the back of the engine should go to the oil pressure switch which operates the oil light on the instrument cluster... the light comes on when the oil pressure switch detects 7psi of pressure or less.