How is it going, I have a 99 Honda civic ex with a d16y8 motor that has a p0325 code for knock sensor circuit, replaced knock sensor, light came back on, tested the harness to look for a shortage, none was found.
How ever I did notice my car was converted to a 5 speed, and also found the ecu that I has is out of a 2000 Honda civic si. My question, is the ecu that I have causing this light to come on?
Thank you in advance!!

 

I would check continuity between the knock sensor plug and the proper pin location at the ECU... and replace the Si (P2T) ECU with an EX manual ECU (P2P).

 

I did check for continuity and I didn't find any shorts in the wire, as I did more research, 00 civic si does use a different part # for the knock sensor, I wonder if the problem could be that the ECU does not recognize the EX sensor, causing the light come on. I may have to replace the ECU like you said.