• Protip: Profile posts are public! Use Conversations to message other members privately. Everyone can see the content of a profile post.

Error Code P0325

7 April 2003
Does anyone have experience with a P0325 error code? Based on the code I know it is for rear knock sensor. Is it critical to replace immediately? How difficult for DIY? Thank you
If it is the sensor you will need to remove the intake manifold to get to it.

Larry, Thank you. I was hoping for an easy repair that I can do myself. I plan to follow the diagnostic instruction on the manual next weekend and hope it is not a bad sensor. Any advice is appreciated.
As to your question of "Is it critical to replace immediately? ", I don't have specific experience with this on the NSX, but I do with other cars. The knock sensor provides feedback for the ECU to set the timing advance. If the sensor is bad, it is possbile for the ECU to advance the timing too far, risking pre-detonation and possible piston damage. If however, when it throws the P0325 code the NSX ECU goes into a somewhat safe mode and retards timing , then there is no risk, just reduced power.

Does anyone know for sure how the NSX ECU handles this case?

Not knowing the specific answer, the "thoughtful driver safe mode" would be to avoid heavy acceleration until the problem is fixed.
Frank, Thank you for the response. I noticed the check engine light when I accelerated above 4500 RPM. I am assuming if I drive with restraint I should be OK. Not sure if it makes a difference, but I did let the car sat for the last two month and if old gas may have caused it. I will trouble shoot this coming weekend.
The knock sensor is under the intake manifold.

What year is your car?
Also, the light only comes on once you go past 4500 rpms? I would def. change the gas out and put fresh gas in it. The knock sensor senses the knock and retards the timing, but the check engine light shouldn't come on. But it the sensor is faulty or broken then yes you will see the light come on.

Make sure you have good ground wire to the engine.

Hope this helps.
I have a 97 NSX-T, six-speed. I drove the car couple times and kept the egine under 4500 RPM and the check engine light has not come on. I plan to check the wiring this weekend. Thank you.
I followed the trouble shooting steps and concluded the code to be an anomaly. I also went back to my maintenance log and realized I had the knock sensor replaced 1 1/2 years and 7K miles ago by my mechanic for close to $700. Thank you all for the help.
So the Bee decided to get "knocked" up today...All my previous codes have always been for lean condition..and that was addressed with sending out injectors for a cleaning.Does the collective know if the ecu has to see a knock 3 times before cel..or is it one time light on? What would be the suggested next step.I will top off tank with new gas.The gas I have is pretty old same as I had after xpo 19...
So, is the Bee storing a P0325 or P0330 error code? If so, parsing the words in the service manual that is an indication that your rear or front knock sensor has died, not that you are suffering from detonation. I suspect that the ECM monitors for a closed or open circuit condition on the sensor or the presence of what is considered to be normal output voltage from the sensor. If it detects a presence of or absence of (normal noise) it assumes your sensor is dead. You can check for an open or short circuit in the wiring; but, if that doesn't yield anything its likely that you are into 'off with the intake manifold'.

If everything is functioning correctly, I am not aware that the CEL will illuminate during a condition where detonation is detected. The common practise is for the ECM to pull the timing to eliminate the knock and then restore timing back to the base map values when the detonation is no longer detected. I don't think there is a 3 knock events and you get a light warning - at least nothing that I could find in the SM.

If you hear actual detonation in the absence of
P0325 or P0330, it is possible that you are exceeding the limits of the ECU to retard the ignition timing sufficiently to eliminate the knock. Very bad gasoline and a heavy foot could test the limits of the ECU to retard the ignition. Getting a fresh dose of 91 or92 may fix the problem. If you hear detonation and you have codes P0325 or P0330, chances are you have a dead sensor(s) with bad gas and a heavy foot being contributory factors.

I have seen some references that claim that bad gas will cause erroneous detection of knock sensor failure. The story goes that the sensor detects some noise that is anomalous (but not detonation???) which triggers the error code for the sensor. The lack of detailed causal analysis makes me put this into the conjecture after a couple of beers category. That doesn't mean it is wrong, just that I am not currently assigning a lot of value to the explanation. That said, dealing with bad gasoline is generally a no cost fix (if you can use the old gas in your lawn mower or ....). Rather than the top up with fresh approach I would be inclined to try and siphon as much of the old stuff out as possible rather than trying the 'solution is dilution' approach.
Thanks mine was the p0325....haha I haven't siphoned gas since the oil embargo...car runs fine.
with the current restaurant decline rodents of all types are becoming more brazen....luckily we are away from urban centers...
I'll have to take a good look around for rodent floculus...:frown:
I haven't siphoned gas since the oil embargo..

1973? I remember that. Empty tank anxiety line ups at US gas stations like the toilet paper anxiety line ups for Covid 19.
yep we lived in Staten Island and gas thieves were everywhere...
....well no rodent detritus.....I erased the code and lets see if it comes back.
Well, if your error code goes away and stays away we can add your evidence to support the
'conjecture after a couple of beers' posit that bad gas can trigger erroneous detection of knock sensor failure. Do report back!
will do. I liked your " no solution with dilution" comment....clever:smile:
After about 50 miles of routine driving and same half tank of gas.............no return of p0325....
So far, better than having to deal with the root-canal associated with intake manifold removal.
Being realistic...Lol electrons have a way of retracing their missteps...:frown:
Its back...................:redface: