avasaka

I'm stumped!

I rebuilt my engine a month ago to fix a few burned out valves (long story) and in the process cleaned everything out really well and replaced anything that looked like it was about to go bad. Of course, the Knock Sensor disintegrated as soon as I touched it. No biggie. Bought a new one on Amazon.

Get the car back together and it runs great! Idles great. Everything is fine EXCEPT it threw a p0325 on the first test drive.

Maybe I screwed up putting the new KS in. Double checked torque, connection, etc. Still CEL.

Okay. Break out the repair manual. Test for continuity between knock sensor harness and ECU. Checks out good. Test for grounding fault. None.

Okay. Maybe a bad part. Order a new KS. Replaced that and.... some thing. CEL.

Sent that back thinking maybe it's because it was another cheapie.

Bought a OEM one. No luck. Double-checked all the wiring again.



Now, I know (from forums and the repair manual) that the next step is ECU replacement. But, clearly that's a bit extreme and given that the ECU was totally fine (no P0325) before the engine rebuild.


Does anyone out there have ANYTHING I can try before buying a new ECU? I don't think there is any fraying in the wires.

(I've even tried checking the voltage while running to see if there is any voltage leakage that happens only when it's on)

rockycat

Re check your timing.

avasaka

thanks! i can give the timing another look; never occurred to me that timing being off would trigger a p0325.

that said i was very careful when setting the timing and even a single tooth off wasn't the case before i buttoned it up... so the only thing that could be off is the tensioner or maybe i locked the harmonic balancer in the wrong position.

i'll give it a reexamination next weekend and post the results.

rockycat

IGN timing can cause a knock or ping and that will set the sensor off.

avasaka

okay, this is a point of confusion for me that i couldn't seem to get a straight answer in all my searching different threads (possibly because it's different for every brand/model?)...


Will (at any point) engine knock actually trigger the knock sensor code P0325?



most posts/threads seem to point to P0325 as being loss of connectivity to the sensor (that is, the minute voltage generated by the sensor isn't getting to the ECU). This seems to be validated by the repair manual test instructions.

some others suggest that P0325 is actually the detection of knock itself. if this is the case a P0325 would seem to prove that the knock sensor is actually working and detecting knock but that the engine itself isn't.

maybe P0325 can be either one?

any clarification would help me immensely!

avasaka

just to make things confusing, i realized i mis-typed the code in the first subject.. the code is P0325 like the posts say NOT P0315 like the thread title says...


P0315 would be a direct link to a timing issue. Is re-checking my timing still something i should do for the P0325?

rockycat

Knock knock who's there? A knock sensor (SENSOR) will see a ping due to bad fuel (low octane) high ign. timing etc.

avasaka

but is detected knock that what actually triggers the Check Engine Light & code? and if so, why does the repair manual have you test wiring connections and not just say, "buy better gas" or "check timing."

presumably engines quite frequently knock and the ECU can control that by automatically making adjustments.

i imagine that if the CEL were triggered every time a knock sensor detects knock every CEL in the world would be on every time someone buys cheap gas.

rockycat

Tests are to make sure the hip bone is connected to the tighe bone. Yes bad gas low octane will set a code every time and thats why it is there.

MAD_MIKE

No.
P0325 - Knock Sensor Circuit Malfunction is the PCM has detected a problem with the circuit, not a code from Knocking/Pinging being detected.

Make sure you are clearing the codes by pulling the PCM memory fuse before rechecking. Some scanners/code readers are not capable of properly clearing the code(s) and only turn off the CEL but leaves the code in the PCM memory. Which will give you a false positive on the code when rechecking again.