Honda P0325 Code & Knock Sensor Replacement 19

The check engine light / engine management light on my Honda CR-V came on recently.  Then it went off…then it came back on again…then it went off again.  You can probably guess what happened next.  In this post I’m going to describe how I worked out what was causing the light to be on, what had gone wrong (knock sensor) and how I fixed it (replaced the sensor).Picture of engine management light on Honda CR-V

The car in question here is a 2004 Honda CR-V with the 2 litre K20A petrol engine.  This engine is found in lots of other Hondas (Accord, Civic, Stream Stepwgn), so hopefully this information will be useful for lots of people.

Obvious and less obvious clues something was wrong

Clearly the obvious clue was when the engine management light came on.  Now I’ve fixed it, I realise the Honda had been giving me subtle clues that something wasn’t right for some time before the light came on.  It wasn’t driving quite as it should, but also wasn’t quite bad enough or annoying enough to make me notice.  Having fixed the problem, I now appreciate there was a slight hesitation when starting to accelerate from idle.

Finding the cause

When the light first came on I stopped as soon as I could to check for obvious signs (or smells) of woe under the bonnet and under the car.  I suggest you do the same if this happens to you.  In my case, everything was fine.

At this point I knew I needed to reach for a code reader.  I used a Foxwell NT200 diagnostic scan tool.

Picture of Foxwell NT200 for reading Honda P0325 code

This is a very cost effective unit but there are a couple of things to be aware of:

  • It can only deal with ECU codes (i.e. not airbag, ABS or other electronic modules).
  • It doesn’t do JOBD, so isn’t suitable for use on Japanese import cars.  JOBD is a version of OBD2 for cars sold in Japan. Check before buying a code reader if you want to use it on an imported car!

Neither of these things were relevant in this situation.

If you haven’t used one of these code readers before, it is very simple:

  1. Find the OBD2 port.  In this case it is in the driver’s footwell, above and to the left of the clutch pedal.Picture of Honda CR-V OBD2 II port
  2. Plug in the reader.
  3. Switch on the ignition.
  4. The code reader gets power from the car, so doesn’t need its own power.
  5. The code reader will communicate with the car’s ECU and report back on whether any codes are stored.  It isn’t completely automatic so you’ll need to click through a few menus.  This reader only has 2 buttons so you can’t go too far wrong.
  6. Navigate through the menus to read the code(s).Picture of finding Honda P0325 code using Foxwell NT200

I was hoping to see a single code show up on the screen rather than a handful of codes, which can be more difficult to diagnose.  Thankfully I was ‘rewarded’ with a single code – P0325, which refers to a fault with the knock sensor.

What is a knock sensor?

We should probably start by covering ‘knock’ itself. It is also known as pinking and refers to the noise produced when the air fuel mixture in the cylinder ignites at the wrong time (i.e. not in response to the spark from the spark plug).

If this keeps happening it can be bad news for your engine.

This is why engines have a knock sensor. This is bolted to the engine block and basically listens out for knocking. When detected, the ECU adjusts the ignition timing or air fuel ratio to stop the knocking.

Fixing Honda P0325 Code – Replacing the Knock Sensor

  1. Start by putting the car on some ramps so you can get underneath.  A jack and axle stands will be fine too, but I find ramps quicker for jobs where I don’t need to take the wheels off.
  2. Lift the bonnet and remove the plastic tray underneath at the front.  Be careful with the trim clips, but some will probably break anyway.  You can use cable ties as a temporary fix if you need to wait for more to arrive.Picture of undertray removed to fix Honda P0325 code
  3. Find the knock sensor.  It’s in a slightly tricky position on the front of the engine block.  The internet is peppered with attempts to video and/or photograph its location.  Here is mine!  I this gives you a rough idea of the location.  The picture was taken with the undertray removed.Picture showing location of knock sensor causing Honda P0325 code
  4. Check the wiring and the existing knock sensor are secure, so you don’t waste money on a new sensor if there is a simpler solution.  In my case, they were, so on to the next step…
  5. …which was to research the likelihood of a fault with another component causing this Honda P0325 code.  This is the second part of ‘trying not to waste money buying unnecessary sensors.’ I didn’t find a great deal of information to suggest this, so set about sourcing a replacement.

Time was not on my side – I was going on holiday in 2 days so didn’t really have time to order online and wait for delivery.  So I contacted my local Honda dealer and was surprised to hear they had one in stock. This confirmed that faults with this knock sensor are common: they wouldn’t keep one in stock unless they sold / replaced quite a few.  We won’t talk about how much it cost!

Picture of knock sensor for fixing Honda P0325 code

On to the replacement procedure.  The instructions could be summarised as follows:

  • Disconnect wire.
  • Undo old knock sensor.
  • Screw in new knock sensor.
  • Reconnect wire.

Fairly straightforward then?  Yes and no, depending on your patience, dexterity and the size of your hands.  Let’s go through the procedure for Honda knock sensor replacement.

  1. Disconnect the battery negative terminal.
  2. Make yourself a coffee / tea / drink of your choice.
  3. Use hands or angled long nose pliers to release the wiring connector from the sensor and remove it.  I did this bit with my hand, but this is tricky because you can’t see what you’re doing!
  4. Loosen the sensor with an open ended 27 mm spanner.  You could also use a 27 mm socket with a universal joint on the end, but you may need to have the UJ only partially inserted into the socket, to give space for the electrical connector on the sensor.  I used this job as an excuse to treat myself to a lovely Facom 27 mm spanner, which was a pleasure to use.Picture of 27mm spanner and socket to fix Honda P0325 code
  5. Make sure the sensor mating surface on the engine block is clean and flat (i.e. remove any grease and rust).
  6. Screw the new sensor into position by hand.
  7. Tighten the new sensor to 31 Nm.
  8. Reconnect the wire to the sensor, making sure the connector clicks into place.
  9. Reconnect the battery.

At this point you can start the engine and (hopefully) enjoy the lack of engine management light on your dashboard.  I connected my fault code reader prior to starting, fully expecting to have to delete the P0325 code, but it had already gone.  This was a good result.  Time to put the undertray back on and go for a test drive.Picture of new knock sensor Honda P0325 code fixed

Honda P0325 Code Summary

We’ve now been through how to identify the Honda P0325 code as a cause of the engine management light coming on.  We’ve looked at how to fix the issue by replacing the knock sensor, using the popular K20A engine in a 2004 Honda CR-V as an example.  I found this a very satisfying fix.  As well as getting rid of the engine management light, and any concerns about engine damage, it actually improved the driving experience too.  There may have been a marginal improvement in fuel consumption, but it is difficult to say for certain because fixing this problem coincided with warmer weather.

I hope this information was useful for you.  If anything wasn’t clear or if you’ve got a question, why not post a comment below?


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19 thoughts on “Honda P0325 Code & Knock Sensor Replacement

  • Baipidi Jim

    My Honda crv 2004 also have knock sound inside the engine and light check engine also appeared, after I have used havoline oil, it just switched off the engine and the little smoke was coming out of dip stick oil hole, help me.

    • Andrew


      Assuming the oil was the correct viscosity and that the level is correct, I can’t see this being caused by using a particular brand of oil. It is very difficult to diagnose a fault without seeing the car, but this sounds like it could be a PCV fault. Have you done a fault code read to see which code caused the engine light to come on?


  • John

    Hi there,
    Thanks for this detailed walk through.
    I’m going to attempt to swap this part out myself.
    I don’t have a torque wrench. Will giving it a good tug be sufficient?

    • John

      Well, I’ve replaced the part and the engine management light has disappeared. I can attest to how awkward this job is. Getting old one out was easy. Getting new one in not so. Had to use a long extending magnet and try to turn it in using fingertips. After an hour and lots of cramp, swearing and cups of tea, it finally played ball. Hope I never have to do it again! Thanks again for your clear and useful guide.

      • Andrew

        Hi John

        Brings back memories of when I did this job!

        I’m really pleased you found my guide useful – thank you for taking the time to say so.


  • Mike

    Thank you for the article, very useful.

    I have a 2005 2.0l CR-V

    I diagnosed my problem with an ODBII scanner I purchased for +-7 pounds (NOTE: Some of these are Android only so make sure if you want iPhone compatible) and purchased the part on The number of knock sensors available to buy told me that this is a very common fault.

    I managed to do this without ramps but did prop the front wheels up on two inch blocks of wood. Obviously judge the safety of this for yourself but even if these blocks failed there was no crush risk, it just allowed some extra elbow room.

    I also chose to use a shifting spanner as I did not have a ring or open face spanner. I would highly recommend not trying this as it makes the job so much more difficult (twice the time at least). Buy the spanner!

    I also did not have a torque wrench so tightened the sensor to about 50% of the pressure I would put on a spark plug. I reconnected the battery and the car has been running fine with no warning lights. This was an intermittent fault so time will tell if this repair worked or not.

  • Ali

    Thanks so much for the detailed information. My car is 2002 CRV and just 2 weeks ago the dealer here in Casablanca brushed me off after charging me for the diagnostics. When i asked why my engine light comes on they told me they ‘ cleared’ the error and nothing to worry about! On my way home the engine light came on again as i expected but i decided not to go back to honda.
    I bought the OBD scanner on line and got the P0325 error and ended up on your solution page thanks to Google.
    My car runs fine other than this minor error light but l will apply your solution when l buy the part required .
    In the meantime wanted to thank you for being a resource to average people like myself.

  • Tuani Annon

    Hi Andrew,
    Very well presented information.
    I had the same problem as described by you with my Honda CRV 2004. When speeding at 60 mph the Check Engine Light comes on, driving locally light goes out. Mechanic diagnosed Knock Sensor, bought a new one got it installed deleted P0325 now the light stays on even in town running. I have changed oil, oil filter and Plugs. OBD still reads Knock Sensor.
    Please advise, Thanks.

    • Andrew

      Hi Tuani

      Difficult to comment without seeing your car, but a few things to consider:

      • Was the new knock sensor definitely the right one for the car?
      • Has it definitely been installed correctly (i.e. all corrosion removed, tightened up properly and the wire reconnected)?
      • Is the wiring between the sensor and engine control module intact?
      • Are there any other fault codes recorded?

      Best wishes

    • Rich

      Iv been having this problem also
      Knock sensor replaced I drove 200meter and light came back on. Took it straight back to garage.
      Same error code as before I believe it says unable to read knock sensor 1.however when the machine is still plugged in. The garage go onto a screen showing the knock sensor and it is reading it but code says it isn’t???? My garage are lost as to why they have had a check of wiring and can’t see any obvious problems. Taking about sending it to a electrics expert.
      Car runs great tho

      • Carlo

        Hello Andrew I have a 2004 Honda CRV, would you be able to tell which part number for the knock sensor subwire? Many thanks

        • Andrew Post author

          Hi Carlo

          Sorry I can’t help with that part number. The parts diagrams I’ve got don’t seem to identify it separately.

          Could the existing one be repaired or are the connectors broken? If you need the part number because you want to buy the part, then a Honda dealer will be able to help. If you want the part number to check equivalent parts, I doubt you’ll find an aftermarket version of that wire.

          Hope you manage to get it sorted.


  • Glynn

    I had mine fixed at my Honda dealer cost £270 all in. I would have done it myself if I had been younger, being over 70 restricts getting up and down.