Hello
Hoping someone can help out. I have a 2002 Accord LX 2.3L. I had the cylinder head off of this car due to 2 burnt exhaust valves. In the process I damaged the knock sensor. I replaced it with an aftermarket sensor (1/3 of the dealer price). The CEL comes on once you hold the RPM's up (approx. 1500+ rpm), and sets the P0325 code for the knock sensor. Clear the code and it only returns if it's off idle (approx. 1500+ rpm). My question is could this be due to the aftermarket sensor or should I be looking elsewhere ? I'm thinking that if it was the wiring it should set the code even at idle. Or does the PCM not monitor the knock sensor at idle. Any help would be greatly appreciated.
Joe

 

Don't see a test for the knock sensor, for the wires yes. Is is possible you damaged the wires?

For the sensor they say to replace with a known good sensor....

 

I did the same thing. I had a bad head gasket and broke the knock sensor off when I was getting stuff off the back of the head. I also bought an aftermarket sensor. That same code came on repeatedly. I've reset it several times. The frequency of the light coming on is going down, but it still comes on. I haven't figured anything out yet either.

 

thanks for the reply poorman.
i dont suspect the wiring because the light doesn't come on if idling, but once u raise rpm's it lights up.
i'm assuming the aftermarket sensor is a "good" one.

 

In the testing, they tell you to hold the rpm's @ 3 to 4 and see if codes sets.

 

I confirmed the wiring is good as per the test.
I removed the KS and replugged the connector and allowed the KS to just dangle there by the harness to see if it would turn the light on even if it's not threaded into the head. Yes It did turn the light back on.
The engine is not making any excessive noises, it's not silent either though.
MY QUESTION
Will the PCM turn the light on if it detects engine knock ?
OR will it turn on the light if it detects engine knock and cannot adjust the timing far enough for the knock to go away ?
Should I just throw an OEM KS at it and hope for the best?
I'd hate to waste $150 or more.
Thanks.

 

P0325 description is "knock sensor circuit problem". I think it would throw a different code if it is detecting knock and can't deal with it.

Hate to throw $100 at it without knowing, but I don't know how to test the actual sensor. The KS is like a microphone, and you probably can use an oscilloscope to watch the signal. Problem is I don't know what a good or bad signal looks like. The PCM is probably not even paying attention to the KS under 1500rpm which explains why it doesn't throw the CEL until going above that.

Judging by the testing that Poorman posted, you rule out any problems with the wiring, the PCM, then replace the sensor. The circuit is dead-simple; just a single wire straight to the PCM. What kind of sensor did you use? I'm sure it's like O2 sensors & spark plugs - Honda doesn't actually make the sensor, it's probably Denso or something like that.

 

Thanks for the reply Jim.
The sensor that I installed is made by "Intermotor genuine import parts"
#KS64. Made in USA by Standard Motor Products.

 

I don't recognize that name, but that doesn't really mean anything bad. Maybe someone who knows will chime in. Even if it's a good brand, they might have mistakenly given you the wrong part?

 

Thanks everyone for the help.
She is fixed. After confirming that the wiring is good. It was either going to be a bad sensor or a bad ecm. I suspected the sensor because it was replaced during the valve job. I didn't believe the ecm would be bad because the light issue wasn't there prior to the work. I got another sensor (same aftermarket brand) and before installing it I ran a thread chaser through the hole (just in case a dirty hole was causing a bad ground path). I have been driving it for 2 days with no problems. Previously it would happen as soon as it warmed up and rpm's increased.